What We Know And Don't Know About Stressful Life Events and Disease Risk

Ten Surprising Facts About Stressful Life Events and Disease Risk. Sheldon Cohen, Michael L.M. Murphy, and Aric A. Prather. Annual Review of Psychology, Vol. 70:577-597. https://doi.org/10.1146/annurev-psych-010418-102857

Abstract: After over 70 years of research on the association between stressful life events and health, it is generally accepted that we have a good understanding of the role of stressors in disease risk. In this review, we highlight that knowledge but also emphasize misunderstandings and weaknesses in this literature with the hope of triggering further theoretical and empirical development. We organize this review in a somewhat provocative manner, with each section focusing on an important issue in the literature where we feel that there has been some misunderstanding of the evidence and its implications. Issues that we address include the definition of a stressful event, characteristics of diseases that are impacted by events, differences in the effects of chronic and acute events, the cumulative effects of events, differences in events across the life course, differences in events for men and women, resilience to events, and methodological challenges in the literature.

Keywords: stressors, life events, health, disease

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REFLECTIONS AND CONCLUSIONS

What We Know About Stressful Life Events and Disease Risk

What we can be sure of is that stressful life events predict increases in severity and progression of multiple diseases, including depression, cardiovascular diseases, HIV/AIDS, asthma, and autoimmune diseases. Although there is also evidence for stressful events predicting disease onset, challenges in obtaining sensitive assessments of premorbid states at baseline (for example, in cancer and heart disease) make interpretation of much of these data as evidence for onset less compelling. In general, stressful life events are thought to influence disease risk through their effects on affect, behavior, and physiology. These effects include affective dysregulation such as increases in anxiety, fear, and depression. Additionally, behavioral changes occurring as adaptations or coping responses to stressors, such as increased smoking, decreased exercise and sleep, poorer diets, and poorer adherence to medical regimens, provide important pathways through which stressors can influence disease risk. Two endocrine response systems, the hypothalamic-pituitaryadrenocortical (HPA) axis and the sympathetic-adrenal-medullary (SAM) system, are particularly reactive to psychological stress and are also thought to play a major role in linking stressor exposure to disease. Prolonged or repeated activation of the HPA axis and SAM system can interfere with their control of other physiological systems (e.g., cardiovascular, metabolic, immune), resulting in increased risk for physical and psychiatric disorders (Cohen et al. 1995b, McEwen 1998).

Chronic stressor exposure is considered to be the most toxic form of stressor exposure because chronic events are the most likely to result in long-term or permanent changes in the emotional, physiological, and behavioral responses that influence susceptibility to and course of disease. These exposures include those to stressful events that persist over an extended duration (e.g., caring for a spouse with dementia) and to brief focal events that continue to be experienced as overwhelming long after they have ended (e.g., experiencing a sexual assault). Even so, acute stressors seem to play a special role in triggering disease events among those with underlying pathology (whether premorbid or morbid), such as asthma and heart attacks.

One of the most provocative aspects of the evidence linking stressful events to disease is the broad range of diseases that are presumed to be affected. As discussed above, the range of effects may be attributable to the fact that many behavioral and physiological responses to stressors are risk factors for a wide range of diseases. The more of these responses to stressful events are associated with risk for a specific disease, the greater is the chance that stressful events will increase the risk for the onset and progression of that disease. For example, risk factors for CVD include many of the behavioral effects of stressors (poor diet, smoking, inadequate physical activity). In addition, stressor effects on CVD (Kaplan et al. 1987, Skantze et al. 1998) and HIV (Capitanio et al. 1998, Cole et al. 2003) are mediated by physiological effects of stressors (e.g., sympathetic activation, glucocorticoid regulation, and inflammation).

It is unlikely that all diseases are modulated by stressful life event exposure. Rare conditions, such as those that are genetic and of high penetrance, leave little room for stressful life events to play a role in disease onset. For example, Tay-Sachs disease is an autosomal recessive disorder expressed in infancy that results in destruction of neurons in both the spinal cord and brain. This disease is fully penetrant, meaning that, if an individual carries two copies of the mutation in the HEXA gene, then they will be affected. Other inherited disorders, such as Huntington’s disease, show high penetrance but are not fully penetrant, leaving room for environmental exposures, behavioral processes, and interactions among these factors to influence disease onset. Note that, upon disease onset, it is unlikely that any disease is immune to the impact of stressor exposure if pathways elicited by the stressor are implicated in the pathogenesis or symptom course of the disease.


What We Do Not Know About Stressful Life Events and Disease Risk

There are still a number of key issues in understanding how stressful events might alter disease pathogenesis where the data are still insufficient to provide clear answers. These include the lack of a clear conceptual definition of what constitutes a stressful event. Alternative approaches (adaptation, threat, goal interruption, demand versus control) overlap in their predictions, providing little leverage for empirically establishing the unique nature of major stressful events. The lack of understanding of the primary nature of stressful events also obscures the reasons for certain events (e.g., interpersonal, economic) being more potent.

Two other important questions for which we lack consistent evidence are whether the stress load accumulates with each additional stressor and whether previous or ongoing chronic stressors moderate responses to current ones. The nature of the cumulative effects of stressors is key to obtaining sensitive assessments of the effects of stressful events on disease and for planning environmental (stressor-reduction) interventions to reduce the impact of events on our health. Evidence that single events may be sufficient to trigger risk for disease has raised two important questions. First, are some types of events more potent than others? Wea ddress this question above (in the section titled Fact 6: Certain Types of Stressful Events Are Particularly Potent) using the existing evidence, but it is important to emphasize the relative lack of studies comparing the impact of different stressors on the same outcomes (for some exceptions, see Cohen et al. 1998, Kendler et al. 2003, Murphy et al. 2015). Second, are specific types of events linked to specific diseases? This question derives from scattered evidence of stressors that are potent predictors of specific diseases [e.g., social loss for depression (Kendler et al. 2003), work stress for CHD (Kivim¨aki et al. 2006)] and of specific stress biomarkers [e.g., threats to social status leading to cortisol responses (Denson et al. 2009, Dickerson & Kemeny 2004)]. While it is provocative, there are no direct tests of the stressor-disease specificity hypothesis. A proper examination of this theory would require studies that not only conduct broad assessments of different types of stressful life events, but also measure multiple unique diseases to draw comparisons. Such studies may not be feasible due to the high costs of properly assessing multiple disease outcomes and the need for large numbers of participants to obtain sufficient numbers of persons developing (incidence) or initially having each disease so as to measure progression. Comparisons of limited numbers of diseases proposed to have different predictors (e.g., cancer and heart disease) are more efficient and may be a good initial approach to this issue.

Another area of weakness is the lack of understanding of the types of stressful events that are most salient at different points in development. For example, although traumatic events are the type of events studied most often in children, the relative lack of focus on more normative events leaves us with an incomplete understanding of how different events influence the current and later health of young people. Overall, the relative lack of comparisons of the impact of the same events (or equivalents) across the life course further muddies our understanding of event salience as we age.

It is noteworthy that the newest generation of instruments designed to assess major stressful life events has the potential to provide some of the fine-grained information required to address many of the issues raised in this review (for a review, see Anderson et al. 2010; see also Epel et al. 2018). For example, the Life Events Assessment Profile (LEAP) (Anderson et al. 2010) is a computer-assisted, interviewer-administered measure designed to mimic the LEDS. Like the LEDS, the LEAP assesses events occurring within the past 6–12 months, uses probing questions to better define events, assesses exposure duration, and assigns objective levels of contextual threat based on LEDS dictionaries. Another instrument, the Stress and Adversity Inventory (STRAIN) (Slavich & Shields 2018), is a participant-completed computer assessment of lifetime cumulative exposure to stressors. The STRAIN assesses a range of event domains and timing of events (e.g., early life, distant, recent) and uses probing follow-up questions. Both the LEAP and the STRAIN are less expensive and time consuming than the LEDS and other interview techniques and are thus more amenable to use in large-scale studies.

The fundamental question of whether stressful events cause disease can only be rigorously evaluated by experimental studies. Ethical considerations prohibit conducting experimental studies in humans of the effects of enduring stressful events on the pathogenesis of serious disease. A major limitation of the correlational studies is insufficient evidence of (and control for) selection in who gets exposed to events, resulting in the possibility that selection factors such as environments, personalities, or genetics are the real causal agents. The concern is that the social and psychological characteristics that shape what types of stressful events people are exposed to may be directly responsible for modulating disease risk. Because it is not possible to randomly assign people to stressful life events, being able to infer that exposure to stressful events causally modulates disease will require the inclusion of covariates representing obvious individual and environmental confounders, as well as controls for stressor dependency—the extent to which individuals are responsible for generating the stressful events that they report.

Even with these methodological limitations, there is evidence from natural experiments that capitalize on real-life stressors occurring outside of a person’s control, such as natural disasters, economic downsizing, or bereavement (Cohen et al. 2007). There have also been attempts to reduce progression and recurrence of disease using experimental studies of psychosocial interventions. However, clinical trials in this area tend to be small, methodologically weak, and not specifically focused on determining whether stress reduction accounts for intervention-induced reduction in disease risk. Moreover, trials that do assess stress reduction as a mediator generally focus on the reduction of nonspecific perceptions of stress and negative affect instead of on the elimination or reduction of the stressful event itself. In contrast, evidence from prospective cohort studies and natural experiments is informative. These studies typically control for a set of accepted potentially confounding demographic and environmental factors such as age, sex, race or ethnicity, and SES. It is also informative that the results of these studies are consistent with those of laboratory experiments showing that stress modifies disease-relevant biological processes in humans and with those of animal studies that investigate stressors as causative factors in disease onset and progression (Cohen et al. 2007).

Despite many years of investigation, our understanding of resilience to stressful life events is incomplete and even seemingly contradictory (e.g., Brody et al. 2013). Resilience generally refers to the ability of an individual to maintain healthy psychological and physical functioning in the face of exposure to adverse experiences (Bonanno 2004). This definition suggests that when a healthy individual is exposed to a stressful event but does not get sick and continues to be able to function relatively normally, this person has shown resilience. What is less clear is whether there are certain types of stressful events for which people tend to show greater resilience than for others. It seems likely that factors that increase stressor severity, such as imminence of harm, uncontrollability, and unpredictability, also decrease an event’s potential to be met with resilience. Additionally, it may be possible that stressful events that are more commonly experienced are easier to adapt to due to shared cultural experiences that provide individuals with expectations for how to manage events. Conversely, less common events (e.g., combat exposure) or experiences that carry significant sociocultural stigma (e.g., rape) might be less likely to elicit resilience. As efforts to test interventions to promote resilience continue to be carried out, careful characterizations of stress exposures, including the complexities discussed in this review, will be critical to understanding the heterogeneity in physical and mental health outcomes associated with stressful life events.


Check also, from 2018...Salutogenic effects of adversity and the role of adversity for successful aging. Jan Höltge. Fall 2018, University of Zurich, Faculty of Arts, PhD Thesis. https://www.bipartisanalliance.com/2019/10/from-2018salutogenic-effects-of.html

And Research has predominantly focused on the negative effects of adversity on health and well-being; but under certain circumstances, adversity may have the potential for positive outcomes, such as increased resilience and thriving (steeling effect):

A Salutogenic Perspective on Adverse Experiences. The Curvilinear Relationship of Adversity and Well-Being. Jan Höltge et al. European Journal of Health Psychology (2018), 25, pp. 53-69. https://www.bipartisanalliance.com/2018/08/research-has-predominantly-focused-on.html

Are Daylight Saving Time Changes Bad for the Brain?

Are Daylight Saving Time Changes Bad for the Brain? Beth A. Malow et al. JAMA Neurol., November 4, 2019. doi:10.1001/jamaneurol.2019.3780

Excerpts (full text, map, references, etc., in the DOI above):

Daylight saving time (DST) begins on the second Sunday in March and ends on the first Sunday in November. During this period, clocks in most parts of the United States are set 1 hour ahead of standard time. First introduced in the United States in 1918 to mimic policies already being used in several European countries during World War I, DST was unpopular and abolished as a federal policy shortly after World War I ended.1 It was reinstated in 1942 during World War II but covered the entire year and was called “war time.” After World War II ended, it became a local policy. Varying DST policies across cities and states led to the Uniform Time Act of 1966, which mandated DST starting on the last Sunday in April until the last Sunday in October. States were allowed to exempt themselves from observing DST (including parts of the state that were within a different time zone [eg, Michigan and Indiana]).

The US Department of Transportation (DOT) is responsible for enforcing and evaluating DST. In 1974, DOT reported that the potential benefits to energy conservation, traffic safety, and reductions in violent crime were minimal.2 In 2008, the US Department of Energy assessed the potential effects to national energy consumption of an extended DST and found a reduction in total primary energy consumption of 0.02%. The DOT is currently reviewing the literature associated with DST in response to a request from the US House Committee on Energy and Commerce.

Since 2015, multiple states have proposed legislation to change their observance of DST (Figure).1,2 These efforts include proposals to exempt a state from DST observance, which is allowable under existing law, and proposals that would establish permanent DST, which would require Congress to amend the Uniform Time Act of 1966.

[Figure]

State Legislation Related to Daylight Saving Time

Map of the United States depicting current practices or legislation pending as of August 2019.1,2 Note the exception of the Navajo Nation in Arizona, which participates in the daylight saving time (DST) transition. Most states have either adopted permanent DST or standard time (ST) or have legislation being considered. While Indiana does not have DST legislation being considered, it is considering legislation in which the entire state would be located within the central time zone.

This Viewpoint reviews data associated with the DST transition. The effects of permanent DST have received less attention and are beyond the scope of this review.

Clinical Implications

The transition to DST has been associated with health consequences, including on cerebrovascular and cardiovascular function. The rate of ischemic stroke was significantly higher during the first 2 days after DST transition, with women, older age, and malignancy showing increased susceptibility.3 A meta-analysis based on several studies including more than 100 000 participants documented a modest increased risk of acute myocardial infarction in the week after the DST spring transition (about 5%).4 This increased risk may be associated with the effect of acute partial sleep deprivation, changes in sympathetic activity with increased heart rate and blood pressure, and the release of proinflammatory cytokines.
The association of DST with self-reported life satisfaction scores was assessed using mixed-effect models and found to be negatively associated with individual well-being.5 The effect of DST was more significant for men and those with full-time employment. In a survey of sleep patterns in 55 000 participants, adjustments to the autumn time zone shift were easier, but adjustments were more difficult in the spring. There was a lower quality of sleep reported in participants up to 2 weeks afterwards during the spring season.6
Using time use data (eg, how individuals spent their time) in the week before and after the transition to DST, the transition to DST resulted in an average of 15 to 20 fewer minutes of sleep.1 High school students studied during the DST transition showed reduced weeknight sleep duration (approximately 30 minutes), as measured by actigraphy.7 The average sleep duration was 7 hours and 51 minutes on pre-DST transition weeknights and 7 hours, 19 minutes post-DST weeknights. In addition, longer reaction times, increased lapses in vigilance, and increased daytime sleepiness were documented. While it is important to recognize that this study only involved 40 students and was limited to the week following the DST transition, an American Academy of Sleep Medicine consensus statement has recommended 8 to 10 hours of sleep for adolescents on a regular basis.8 These recommendations were based on a detailed literature review that documented adverse effects of chronic sleep loss on attention, behavior, learning problems, depression, and self-harm. Additional studies will be needed to document whether transitions to DST have more long-term associations with adolescent sleep and contribute to adverse effects.

Genetics of Circadian Disruption

The negative health outcomes associated with the DST transition may be associated with disruptions in the underlying genetic mechanisms that contribute to the expression of the circadian clock and its behavioral manifestations in neurology (ie, chronotype).9 It is well established that genetic factors help to regulate the sleep-wake cycle in humans by encoding the circadian clock, which is an autoregulatory feedback loop. When sleep time shifts there is global disruption in peripheral gene expression, and even the short-term sleep deprivation that occurs following the transition to DST may alter the epigenetic and transcriptional profile of core circadian clock genes.10 While it is unclear how disruptive a 1-hour time change is to otherwise healthy individuals, it is possible that individuals with extreme manifestations of chronotype or circadian rhythm sleep-wake disorders, neurological disorders, or children and adolescents whose brains are still developing are more susceptible to the adverse health effects that occur following the DST transition.

Conclusions
Transitions to DST have documented detrimental associations with the brain, specifically ischemic stroke, with the risk of myocardial infarction and well-being also affected. A lower quality of sleep, shorter sleep duration, and decreased psychomotor vigilance have also been reported. Additional studies are needed to understand the causes of these detrimental effects and the role of sleep deprivation and circadian disruption. Based on these data, we advocate for the elimination of transitions to DST.

From 2018... A Simple Combinatorial Model of Technological Change that Explains the Industrial Revolution

From 2018... A Simple Combinatorial Model of World Economic History. Roger Koppl, Abigail Devereaux, Jim Herriot, Stuart Kauffman. Nov 2018. arXiv:1811.04502

Abstract: We use a simple combinatorial model of technological change to explain the Industrial Revolution. The Industrial Revolution was a sudden large improvement in technology, which resulted in significant increases in human wealth and life spans. In our model, technological change is combining or modifying earlier goods to produce new goods. The underlying process, which has been the same for at least 200,000 years, was sure to produce a very long period of relatively slow change followed with probability one by a combinatorial explosion and sudden takeoff. Thus, in our model, after many millennia of relative quiescence in wealth and technology, a combinatorial explosion created the sudden takeoff of the Industrial Revolution.

Men speak more abstractly than women; gender differences were larger for older adults than for teenagers, suggesting that gender differences in communicative abstraction may be reinforced by one’s experiences

Gender differences in communicative abstraction. Joshi, Priyanka D., Wakslak, Cheryl J., Appel, Gil, Huang, Laura. Journal of Personality and Social Psychology, Oct 14 , 2019. https://psycnet.apa.org/doiLanding?doi=10.1037%2Fpspa0000177

Abstract: Drawing on construal level theory, which suggests that experiencing a communicative audience as proximal rather than distal leads speakers to frame messages more concretely, we examine gender differences in linguistic abstraction. In a meta-analysis of prior studies examining the effects of distance on communication, we find that women communicate more concretely than men when an audience is described as being psychologically close. These gender differences in linguistic abstraction are eliminated when speakers consider an audience whose distance has been made salient (Study 1). In studies that follow, we examine gender differences in linguistic abstraction in contexts where the nature of the audience is not specified. Across a written experimental context (Study 2), a large corpus of online blog posts (Study 3), and the real-world speech of congressmen and congresswomen (Study 4), we find that men speak more abstractly than women. These gender differences in speech abstraction continue to emerge when subjective feelings of power are experimentally manipulated (Study 5). We believe that gender differences in linguistic abstraction are the result of several interrelated processes—including but not limited to social network size and homogeneity, communication motives involving seeking proximity or distance, perceptions of audience homogeneity and distance, as well as experience of power. In Study 6, we find preliminary support for mediation of gender differences in linguistic abstraction by women’s tendency to interact in small social networks. We discuss implication of these gender differences in communicative abstraction for existing theory and provide suggestions for future research.

General Discussion

Across a series of six studies, we find that men communicate more abstractly than women. We find that gender differences in communicative abstraction persist across experimental (Studies 1, 2, 5, and 6) and field (Studies 3 and 4) contexts. The effects conceptually replicate across various measures of abstraction, including emphasizing desirability vs. feasibility (Study 2), using more concrete words (Studies 3 and 4), and adopting higher levels of action identification (Studies 5 and 6).

Effects ranged from small to moderate across studies, with larger effect sizes in our controlled laboratory-style studies than our archival data ones. The former studies allowed for greater control, constraining the topic of communication and potential ways in which a participant was able to communicate. They largely also used paradigms that have been specifically designed in prior work to capture variation in communicative abstraction. On the other hand, our archival data studies gave us an opportunity to examine gender differences in contexts that were much less constrained in terms of numerous factors such as the topic of conversation, number of words, intended audience, length of speech, and overall purpose of conversation. Given the size of the corpora involved, they also relied on an automated method for coding abstraction, which gives up some amount of precision compared to hand coding (see Johnson et al., 2019, for a related discussion). Thus, it is not especially surprising to find smaller effects in these contexts.

What Drives these Effects?

We suspect that the gender difference in communicative abstraction we identify emerges from a set of converging reasons, including women’s social interactions in closely knit small groups, their historical occupation of lower status roles compared to men, their desire to establish close interpersonal relationships, their caution in signaling power and judgmentalness, and their desire to establish their competence. While we do not argue for any one particular process, several of our specific findings across studies may speak to the various (potentially interrelated) processes that might underlie this effect.

For example, in Study 1, we find that when an audience’s distance is made salient, gender differences in linguistic abstraction are eliminated. The moderating role of distance is consistent with this factor playing a role in explaining gender differences in communicative abstraction. That is, women may be relatively more inclined to create proximity with others (indeed, we found this gender pattern in Study 6, although it did not negatively correlate with the use of abstraction) or to conceptualize others as proximal; emphasizing that an audience is distant may block the proximating tendency of women and minimize gender effects in communication. Also important to consider in the context of Study 1’s findings are our findings in Study 3, which showed differences in the communicative abstraction of male and female bloggers. On the one hand, this may be surprising given Study 1’s findings (given that bloggers communicate with a sizeable audience). At the same time, unlike the experimental studies on audience size which made salient the size and/or heterogeneity of the audience and likely reduced variation in perceptions of it, the blogging context preserves the opportunity for variation in perception of one’s audience. For example, female bloggers may differ from male bloggers in terms of their perception of their audience’s homogeneity, size, and similarity to themselves; although speculative, such variation may support the emergence of gender differences in communicative abstraction within the blogging context.

We also considered the role of power in explaining gender effects on communicative abstraction. Across samples, we find effects both when respondents have relatively low levels of power (e.g., students, Mturk respondents) and when they have higher levels of power (members of Congress). Indeed, even within our Congress dataset (Study 4) we find no variation in the gender effect based on relative amount of power (House of Representative members vs. Senators). This is consistent as well with results of Study 5, which experimentally manipulated power and found that this did not interact with gender. These findings, however, do not preclude a role of the subjective experience of power. That is, even when in similar positions, men and women may differ in how powerful they feel. Study 5, which found that women reported lower subjective experience of power than men when power was experimentally primed, and that this subjective experience of power mediated the effects of gender on communicative abstraction, is consistent with a role of subjective power in explaining gender differences in speech. In Study 6, however, we did not find any evidence for gender differences in subjective experience of power, and subjective experience of power did not mediate the effects of gender on communicative abstraction. This suggests at a broad level that while subjective power may play a role in some contexts (e.g., most likely ones in which subjective power is salient, as in Study 5), the routine experience of power is unlikely to be the main driver of these gender effects across variable contexts.

Indeed, in Study 6 we considered a broader set of mediators of a gender effect on abstraction. Gender differences on the measures we collected supported many of our earlier arguments based on the gender literature: women reported greater motivation than men to seek closeness in communication contexts, greater likelihood of interacting in small and homogeneous networks, and greater concerns about establishing their competence. Further, we found that the tendency of women to establish and interact in small groups mediated their tendency to use concrete speech. As mentioned earlier, we certainly don’t see these results as ruling out alternative explanations, but they do suggest the plausibility of communication audience size playing an important role.

Also thought-provoking are the findings from Study 3. In a dataset that allowed us to capture writings of adolescents as well as adults, we found that gender differences were larger for older adults than for teenagers, suggesting that gender differences in communicative abstraction may be reinforced by one’s experiences. This is broadly consistent with our argument that women and men are acculturated in a variety of ways over time that are consistent with the development of different communicative abstraction tendencies. We call for future work to continue to explore this divergence in women and men’s speech, and how these are shaped through one’s interpersonal experiences.

Lando's data — the overall positive experience of his hospitalization — didn’t match David Rosenhan’s thesis that institutions are uncaring, ineffective and even harmful places, and so they were discarded

Stanford professor who changed America with just one study was also a liar. Susan Cahalan. NY Post, Nov 2 2019. https://nypost.com/2019/11/02/stanford-professor-who-changed-america-with-just-one-study-was-also-a-liar/

About Stanford psychology and law professor David Rosenhan and his work

[...]

His research work was also groundbreaking. In 1973, Rosenhan published the paper “On Being Sane in Insane Places” in the prestigious journal Science, and it was a sensation. The study, in which eight healthy volunteers went undercover as “pseudopatients” in 12 psychiatric hospitals across the country, discovered harrowing conditions that led to national outrage. His findings helped expedite the widespread closure of psychiatric institutions across the country, changing mental-health care in the US forever.

Fifty years later, I tried to find out how Rosenhan had convinced his subjects to go undercover as psychiatric patients and discovered a whole lot more. Yes, Rosenhan had charm. He had charisma. He had chutzpah to spare. And, as I eventually uncovered, he was also not what he appeared to be.

I stumbled across Rosenhan and his study six years ago while on a book tour for my memoir “Brain on Fire,” which chronicled my experiences with a dangerous misdiagnosis, when doctors believed that my autoimmune disorder was a serious mental illness. After my talk, a psychologist and researcher suggested that I could be considered a “modern-day pseudopatient” from Rosenhan’s famous study.

Rosenhan’s eight healthy pseudopatients allegedly each followed the same script to gain admittance to psychiatric hospitals around the country. They each told doctors that they heard voices that said, “Thud, empty, hollow.” Based on this one symptom alone, the study claimed, all of the pseudopatients were diagnosed with a mental illness — mostly schizophrenia.

And once they were labeled with a mental illness, it became impossible to prove otherwise. All eight were kept hospitalized for an average of 19 days — with the longest staying an unimaginable 52. They each left “against medical advice,” meaning the doctors believed that they were too sick to leave. A total of 2,100 pills — serious psychiatric drugs — were reportedly prescribed to these otherwise healthy individuals.

At the time, the collective American imagination was deeply suspicious of psychiatry and its institutions. It was the era of Ken Kesey’s “One Flew Over the Cuckoo’s Nest” and movies like “Shock Corridor” and “The Snake Pit.” Rosenhan — who was both an insider who studied abnormal psychology, and an outsider who was a psychologist rather than a psychiatrist — was the perfect person to pull back the curtain on psychiatry’s secrets.

[...]

“It all started out as a dare,” Rosenhan told a local newspaper. “I was teaching psychology at Swarthmore College, and my students were saying that the course was too conceptual and abstract. So I said, ‘OK, if you really want to know what mental patients are like, become mental patients.’ ”

Soon after that, Rosenhan went undercover for nine days at Haverford State Hospital in Haverford, Pa., in February 1969. His diary and book describe a host of indignities: soiled bathrooms without doors, inedible food, sheer boredom and ennui, rank disregard by the staff and doctors. Rosenhan even witnessed an attendant sexually assault one of the more disturbed patients. The only time when Rosenhan was truly “seen” as a human by the staff was when an attendant mistook him for a doctor.

The experience was harrowing. After nine days he pushed for a release and made sure that his undergraduate students — who were planning to follow him as undercover patients into the hospital — would not be allowed to go. Colleagues described a shaken, changed man after his experience.

I dug deeper. If his own students were forbidden from pursuing the experiment after this dismaying event, who were the others who had willingly followed in Rosenhan’s footsteps? Why did they put their mental health — even their lives — on the line for this experiment?

The further I explored, the greater my concerns. With the exception of one paper defending “On Being Sane in Insane Places,” Rosenhan never again published any studies on psychiatric hospitalization, even though this subject made him an international success.

He had also landed a lucrative book deal and had even written eight chapters, well over a hundred pages of it. But then Rosenhan suddenly refused to turn over the manuscript. Seven years later his publisher sued him to return his advance. Why would he have given up on the subject that made him famous?

I also started to uncover serious inconsistencies between the documents I had found and the paper Rosenhan published in Science. For example, Rosenhan’s medical record during his undercover stay at Haverford found that he had not, as he had written in his published paper, only exhibited one symptom of “thud, empty, hollow.” Instead, he had told doctors that he put a “copper pot” up to his ears to drown out the noises and that he had been suicidal. This was a far more severe — and legitimately concerning — description of his illness than he had portrayed in his paper.

Meanwhile, I looked for the seven other pseudopatients and spent the next months of my life chasing ghosts. I hunted down rumors, pursuing one dead end after the next. I even hired a private detective, who got no further than I had.

After years of searching, I found only one pseudopatient who participated in the study and whose experience matched that of Rosenhan: Bill Underwood, who’d been a Stanford graduate student at the time.

The only other participant I discovered, Harry Lando, had a vastly different take. Lando had summed up his 19-day hospitalization at the US Public Health Service Hospital in San Francisco in one word: “positive.”

Even though he too was misdiagnosed with schizophrenia, Lando felt it was a healing environment that helped people get better.

“The hospital seemed to have a calming effect. Someone might come in agitated and then fairly quickly they would tend to calm down. It was a benign environment,” Lando, now a psychology professor at the University of Minnesota, recalled in an interview.

But instead of incorporating Lando into the study, Rosenhan dropped him from it.

Lando felt it was pretty obvious what had happened, and I agree: His data — the overall positive experience of his hospitalization — didn’t match Rosenhan’s thesis that institutions are uncaring, ineffective and even harmful places, and so they were discarded.

“Rosenhan was interested in diagnosis, and that’s fine, but you’ve got to respect and accept the data, even if the data are not supportive of your preconceptions,” Lando told me.

Rosenhan, I began to realize, may have been the ultimate unreliable narrator. And I believe it’s possible some of the other pseudopatients he mentioned in his study never existed at all.

As a result, I am now seriously questioning a study I had once admired and had originally planned to celebrate. In my new book “The Great Pretender” (Grand Central Publishing), out this week, I paint the picture of a brilliant but flawed psychologist who is likely also a fabulist.

[...]

Psychologist Peter Gray told me that he sees the work of researchers such as Zimbardo and Rosenhan as prime examples of studies that “fit our biases … There is a kind of desire to expose the problems of society but in the process cut corners or even make up data.”

This may explain Rosenhan. He saw real problems in society: The country was warehousing very sick people in horror houses pretending to be hospitals, our diagnostic systems were flawed and psychiatrists in many ways had too much power — and very little substance. He saw how psychiatric labels degraded people and how doctors see patients through the prism of their mental illness. All of this was true. In many ways, it is still true.

[...]


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Check also Pseudopatient or pseudoscience: a reviewer's perspective. Mark Zimmerman. Journal of Nervous & Mental Disease 193(11):740-2, December 2005. https://www.researchgate.net/publication/7506090

Pattern of conditional party loyalty... While partisan loyalty is strong, it is finite: the average voter is more likely than not to vote for the co-partisan candidate until that candidate takes dissonant stances on four or more salient issues

The Limits of Partisan Loyalty. Jonathan Mummolo, Erik Peterson, Sean Westwood. Political Behavior, November 4 2019. https://link.springer.com/article/10.1007/s11109-019-09576-3

Abstract: While partisan cues tend to dominate political choice, prior work shows that competing information can rival the effects of partisanship if it relates to salient political issues. But what are the limits of partisan loyalty? How much electoral leeway do co-partisan candidates have to deviate from the party line on important issues? We answer this question using conjoint survey experiments that characterize the role of partisanship relative to issues. We demonstrate a pattern of conditional party loyalty. Partisanship dominates electoral choice when elections center on low-salience issues. But while partisan loyalty is strong, it is finite: the average voter is more likely than not to vote for the co-partisan candidate until that candidate takes dissonant stances on four or more salient issues. These findings illuminate when and why partisanship fails to dominate political choice. They also suggest that, on many issues, public opinion minimally constrains politicians.

Keywords: Party cues Public opinion Voting

Making the Right First Impression: Sexual Priming Encourages Attitude Change and Self-Presentation Lies during Encounters with Potential Partners

Making the Right First Impression: Sexual Priming Encourages Attitude Change and Self-Presentation Lies during Encounters with Potential Partners. Gurit E Birnbaum, Mor Iluz, Harry Reis. Journal of Experimental Social Psychology 86 (2020) 103904. DOI: 10.1016/j.jesp.2019.103904

Abstract: Recent studies have shown that activation of the sexual system encourages enactment of relationship-initiating behaviors (Birnbaum et al., 2017). In four studies, we expand on this work to explore whether people are more inclined to lie to impress a potential partner following sexual priming. In all studies, participants were exposed to sexual stimuli (versus non-sexual stimuli) and then interacted with an opposite-sex stranger. In Study 1, unacquainted participants resolved a dilemma while each represented opposing positions. In Study 2, participants rated their preferences, and after viewing a confederate's preferences, re-rated them in a profile shown to the confederate. In Studies 3 and 4, participants reported their number of lifetime sexual partners in anonymous questionnaires and during a chat (Study 3) or while completing an online profile (Study 4). Results indicated that following sexual priming, participants were more likely to conform to the stranger's views (Studies 1 and 2) and reported fewer sexual partners during actual and potential online interactions than in the questionnaires (Study 3). Although the results of Study 4 did not replicate the findings of Study 3, they were directionally consistent with them. Overall, the findings suggest that sexual priming motivates impression management even when it involves lying.

6. General discussion

In a world of seemingly abundant mating opportunities, competing
for a partner has become a challenging endeavor. In this climate, people
do the best they can to attract desirable partners. Investing effort in
making the right impression plays a key role in the success of their
pursuit. When considering the impression they wish to leave on prospective
partners, people are simultaneously motivated by the competing
desires of being wanted for whom they truly are and of putting
forward their best face (Ellison et al., 2006; Toma et al., 2008). The
present research set out to examine when the latter motivation would
prevail, pushing people to impress a potential partner even at the cost
of engaging in deceptive self-presentation.
In four studies, we showed that following activation of the sexual
system, people were more likely to enhance their efforts to create a
favorable impression and deceptively change their self-presentation in
an attempt to appear more desirable to prospective mates. Study 1 indicated
that compared to participants in the control condition, participants
in the sexual activation condition were more likely to outwardly
express agreement with a contrary opinion advocated by an oppositesex
participant. Study 2 showed that subliminal sexual priming led
participants to conform to a potential partner's preferences in various
life domains. Studies 3 and 4 revealed that following sexual priming,
participants were more likely to lie to a potential mate about their
number of lifetime sexual partners.
Past studies have already shown that activation of the sexual system
motivates people to use strategies that help them initiate a relationship
with potential mates, such as disclosing personal information or providing
help (Birnbaum et al., 2017; Birnbaum et al., 2019). The present
research extends these studies by demonstrating the dark side of relationship
initiation (or a human foible that reveals itself during this
process) and pointing out when it is likely to surface. Scholars and lay
persons alike have long recognized that relationship-initiating strategies
include enactment of behaviors that aim not only to genuinely
support long-term bonding (e.g., provision of responsiveness and help;
Birnbaum, Ein-Dor, Reis, & Segal, 2014; Birnbaum et al., 2019) but also
to deliberately mislead prospective partners (e.g., Rowatt et al., 1998;
Toma et al., 2008). Our research speaks to one important psychological
circumstance under which certain self-presentational goals may become
more pronounced. Specifically, exposure to sexual cues, which activates
the sexual system and induces sexual arousal, may render people more
determined in their pursuit of desirable mates, encouraging them to
present a shiny façade, even though presenting a distorted view of self
may eventually thwart their goal of establishing a trustworthy intimate
relationship.
As our research indicates, this principle appears to hold true for
both men and women. Previous studies have found that men are more
likely than women to take the lead in sexual and relationship initiation
(Birnbaum & Laser-Brandt, 2002; Diamond, 2013; O'Sullivan & Byers,
1992). The present findings suggest that activation of the sexual system
motivates human beings to connect, regardless of gender. It does so by
inspiring interest in potential partners and motivating men and women
to impress prospective partners. To be sure, missing desirable mating
opportunities is costly for men and women alike, in the sense that when
such opportunities arise, both genders, and not only men, tend to use
deceptive self-presentational strategies (Lo et al., 2013; Rowatt et al.,
1999).
It remains unclear, however, whether deceptive self-presentation in
this context is motivated by short-term relationship goals or by selfpresentational
pressures per se, as both may be more salient under
sexual activation. Indeed, when sexually aroused, some people may
present themselves deceitfully to potential mates in order to obtain
casual sexual favors (Ariely & Loewenstein, 2006). Others, in contrast,
may wish to build a meaningful relationship but are induced by their
insecurities or perceived competition in the dating scene to present a
false façade. Indeed, people themselves may not be able to distinguish
short-term (sexual) and long-term (relationship initiation) goals in their
initial phases of attraction (Eastwick, Keneski, Morgan, McDonald, &
Huang, 2018).
Another limitation of the present research is that the evidence for
the proposed effect of sexual priming on explicit lying about previous
sexual partners is not strong, given that we found a non-significant
interaction in Study 4, which was better-powered than Study 3. It is
possible that conforming to a potential partner's views while being
sexually aroused (as indicated in Studies 1 and 2) is morally less problematic
than explicitly lying to a potential partner, especially in the
case of violating one's own earlier statements (Batson, Thompson,
Seuferling, Whitney, & Strongman, 1999). It is also possible that Study
4 yielded weaker results than Study 3 due to less experimental realism –
recall that Study 4 was conducted entirely online, whereas participants
in Study 3 were present in a lab session. We also did not determine
whether participants were aware of their deception or whether this was
an unconscious move to be closer to a potential partner and did not
assess the motives behind engaging in deceptive self-presentation. Future
studies should investigate how these distinctive motives affect the
unfolding over time of interactions that are based on deceptive communication
and whether they may evolve into meaningful relationships.
Further research should explore whether people also tend to see
what they want to see while being sexually aroused and thus are less
likely to detect inauthenticity in potential partners.
In conclusion, activation of the sexual system may initiate a process
of endeavoring to become more attractive to a stranger, a process that
may eventually build an emotionally and sexually satisfying connection
between previously unacquainted people (Birnbaum, 2018; (Birnbaum
and Finkel, 2015) Birnbaum et al., 2019; Birnbaum & Reis, 2019). In
everyday life, the attractiveness of a potential partner or the sexy ambience
of a first date may lead people to disclose personal information
about themselves in order to initiate a potential relationship with a
desired mate (Birnbaum et al., 2017). Our research suggests that the
content of this disclosure is less likely to reflect the true self following
sexual activation, as sexual arousal may make people more focused on
saying what needs to be said to create a positive impression while being
less cognizant of the potential long-term costs of this tendency. Our
research also underscores the dual potential of the sexual system for
eliciting behavior that may simultaneously facilitate relationship initiation
while at the same time undermining their authenticity. Whether
sexual arousal heightens perceptions of a prospective partner's mate
value, creates a state of urgency, or instills a sense partner scarcity is a
question for future research.

An RT/fMRI study showed a single cluster of activity that pertains to logical negation, distinct from clusters that were activated by numerical comparison and from the traditional language regions

Logical negation mapped onto the brain. Yosef Grodzinsky et al. Brain Structure and Function, November 4 2019. https://link.springer.com/article/10.1007/s00429-019-01975-w

Abstract: High-level cognitive capacities that serve communication, reasoning, and calculation are essential for finding our way in the world. But whether and to what extent these complex behaviors share the same neuronal substrate are still unresolved questions. The present study separated the aspects of logic from language and numerosity—mental faculties whose distinctness has been debated for centuries—and identified a new cytoarchitectonic area as correlate for an operation involving logical negation. A novel experimental paradigm that was implemented here in an RT/fMRI study showed a single cluster of activity that pertains to logical negation. It was distinct from clusters that were activated by numerical comparison and from the traditional language regions. The localization of this cluster was described by a newly identified cytoarchitectonic area in the left anterior insula, ventro-medial to Broca’s region. We provide evidence for the congruence between the histologically and functionally defined regions on multiple measures. Its position in the left anterior insula suggests that it functions as a mediator between language and reasoning areas.

Keywords: Language Logic Numerosity Functional neuroanatomy Functional neuroimaging Cytoarchitecture Brain mapping Negation Sentence verification Left anterior insula Modularity

Discussion 
Taken together, the anatomical and functional clusters exhibit bi-uniqueness: area Id7 is cytoarchitectonically distinct from its neighbors, and represents a new, independent cortical area of the anterior insula (Fig. 7, Movie). The functional NetNegInt coincides largely with Id7, overlaps with no other cortical region, and NetNegInt intensity correlates with RT at the individual participant level. 

At a minimum, these results allow us to conclude that there is a single, anatomically and functionally cohesive core area involved in negation—Id7/NetNegInt. It is distinct from areas 44, 45, long believed to support syntax and from areas supporting core compositional semantic processes in the left temporal pole (Del Prato and Pylkkänen 2014). This distinctness and cohesiveness illustrates how relatively small elements of cognition can be neurally individuated and correlated with cytoarchitectonically defined areas. It also supports a modular view of cognitive functioning (Fodor 1983) and moreover seems to provide an answer, albeit partial, to the perennial debate about language and logic. If evidence from neuroscience bears on the debate, then Frege, Russell, and their followers were right: language and at least some aspects of logic are distinct. Finally, our results suggest that the border between the insula and Broca’s region is where language stops and logic begins.

We are not in a position to establish a connection between our results and other roles attributed to the anterior insula such as interoception. Yet, there is a differ-ence in pattern: typically, the anterior insula is activated bilaterally (Zaccarella and Friederici 2015), and tends to co-activate with the anterior cingulate (Craig 2009; Engstrom et al. 2014), to which the left and right insulae appear to be massively connected (Mesulam and Mufson 1982) and have a similar histologic makeup (Ghaziri et al. 2017). Our study documented no bi-lateral co-activation. Recent lesion data, moreover, relate interoceptive deficits to regions that seem to exclude the here defined left Id7 (Salomon et al. 2018).

So what can we conclude and where do we go from here? Our experiment demonstrates that the processing of one log-ical connective, ¬, has a distinct neurocognitive signature, supported by a histologically coherent piece of neural tissue, the left Id7, that is, outside the traditional language regions, lying between them and decision making areas. While we believe that this set of findings provides the basis for an important argument for language–logic dissociation, we are aware that it is based on a single set of results, one that needs to be further enriched in the same spirit. Convergent results from related explorations of other logical connectives will no doubt help to bolster our claims. E.g., if experiments can be designed to successfully isolate disjunction, conjunction, and the like, and their results converge, solid foundations for a new perspective on language–logic relations would be constructed. 

ith this qualification, can we conclude that the phi-losophers were right? Gottlob Frege, in his Begriffschrift, famously asserted that linguistic rules relate to logic as the eye compares to a microscope (van Heijenoort 1967): language is flexible, but logic is more rigid—mediating between linguistic expressions and objects suitable to reasoning. While Frege and Russell had no cognitive perspective, let alone a neurological one, we feel free to add one and assign an anatomical construal of Frege’s assertion in regards to the spatial position of the left Id7: like a microscope, this area may “translate” linguistic objects into logical forms. A mediating role has already been proposed for the posteriorly adjacent, middle left insula, claimed to mediate between motor planning and speech (Dronkers 1996). In a similar vein, it is proposed that the left Id7 mediates between the language regions and prefrontal areas engaged in reasoning (Baggio et al. 2016; Monti et al. 2007). By doing so, it seems to play a crucial role in what could be a core neural network that underlies our humanity.

Taking Close Others' Environmental Behavior Into Account When Striking the Moral Balance? Evidence for Vicarious Licensing, Not for Vicarious Cleansing

Meijers, M. H. C., Noordewier, M. K., Verlegh, P. W. J., Zebregs, S., & Smit, E. G. (2019). Taking Close Others' Environmental Behavior Into Account When Striking the Moral Balance? Evidence for Vicarious Licensing, Not for Vicarious Cleansing. Environment and Behavior, 51(9-10), 1027–1054. https://doi.org/10.1177/0013916518773148

Abstract: Research shows that people search for balance in their moral (e.g., environmentally friendly) behaviors such that they feel licensed to behave less morally after a previous moral act (licensing) and cleanse previous morally questionable behaviors by subsequently behaving more morally (cleansing). This article investigates whether this balancing may extend to close others, but not to nonclose others, and tests vicarious licensing and cleansing in the environmental domain. Study 1 showed that vicarious licensing effects are more likely when a close other displayed environmentally friendly (vs. neutral) behavior. Study 2 showed that environmental vicarious licensing effects are more likely for close than nonclose others. Studies 3 and 4 suggested that vicarious licensing effects, but not vicarious cleansing effects are more likely for close (vs. nonclose) others. Finally, a meta-analysis showed that overall these studies provide evidence for vicarious licensing effects, but not for vicarious cleansing effects in the environmental domain.

Keywords: environmentally friendly, licensing, cleansing, vicarious, self–other overlap, morality

Research shows that people search for balance in their moral behaviors (e.g., environmentally friendly behaviors) such that they feel licensed to behave less morally after a previous moral act (i.e., licensing effect) and cleanse pre-vious morally questionable behaviors by subsequently behaving morally (i.e., cleansing effect; Monin & Miller, 2001; Sachdeva, Iliev, & Medin, 2009; Tetlock, Kristel, Elson, Green, & Lerner, 2000). In the present research, it is investigated whether people extend this moral balancing to incorporate not only their own moral behaviors but also the behaviors of close others. To illustrate, one may think of those who feel licensed to buy a less environmentally friendly product after their close friend has made a donation to Greenpeace, or those who meticulously separate their garbage after their spouse bought a new car with poor fuel economy.Literature suggests that considerable self–other overlap may occur when people feel close to another person (Aron, Aron, Tudor, & Nelson, 1991), and that the actions of close others may be perceived to some extent as actions of themselves (Goldstein & Cialdini, 2007). In other words, people incorporate the behaviors of close others into their own self-concepts. Based on this reasoning, it is posited that moral behaviors of close others may lead to vicarious licensing effects, and that the morally questionable behaviors of close others might lead to vicarious cleansing effects in the environmental domain. In this article, it is hypothesized that the strength of these effects depends on the degree of interpersonal closeness: When people are close to another person they are more likely to vicariously balance each other’s moral behaviors than when they are not close. In the remainder of the article, we will elaborate on the theoretical background for this proposition and report four studies and a meta-analysis testing this proposition in the context of environmentally friendly behaviors. Support is found for vicarious licensing effects, but not for vicarious cleansing effects.

Great apes are not vulnerable to the cognitive biases that cause decoy effects in humans, at least in cases where choice is between two different types of food

Sánchez-Amaro, A., Altınok, N., Heintz, C., & Call, J. (2019). Disentangling great apes’ decoy-effect bias in a food choice task. Animal Behavior and Cognition, 6(3), 213–222. https://doi.org/10.26451/abc.06.03.05.2019

Abstract: The decoy effect is a violation of rationality that occurs when the relative preference between two target options changes with the addition of a third option, called the decoy, that is no better than the target options but worse than one of the options on one attribute. The presence of the decoy increases the chance that the option that dominates it on this attribute is chosen over the other target option. The current study tested decoy effects with great apes’ food preferences. We presented apes with two target items, grape and banana, and a third item, the decoy, which was either a smaller grape or a smaller piece of banana. We found that apes’ decisions were not influenced by the presence of a decoy. In general, apes did not increase their choices in favor of the target item that dominated the decoy. This would indicate that great apes are not vulnerable to the cognitive biases that cause decoy effects in humans, at least in cases where choice is between two different types of food. We discuss what can be concluded about the psychological causes of human irrational choices and their evolutionary origin.

Keywords: Decoy-effect, Rationality, Great apes, Food preferences

An Examination of the Sexual Double Standard Pertaining to Masturbation and the Impact of Assumed Motives

An Examination of the Sexual Double Standard Pertaining to Masturbation and the Impact of Assumed Motives. Katherine R. Haus, Ashley E. Thompson. Sexuality & Culture, November 2 2019. https://link.springer.com/article/10.1007/s12119-019-09666-8

Abstract: Research reveals that masturbation is a highly stigmatized behavior for which people are harshly judged. Stigmatized sexual behaviors often result in discrepancies in social judgment such as the Sexual Double Standard (SDS; the tendency to judge women’s sexual behavior more harshly than men’s). However, no research has experimentally examined the SDS with respect to masturbation or the assumed motives influencing the potential SDS. Thus, in study one, a total of 496 U.S. adults (246 women, 250 men) were required to read one of four vignettes depicting a hypothetical man or woman engaged in masturbation. After reading the vignette, the endorsement of the SDS was assessed by asking participants to rate the perceived partner quality of the hypothetical masturbator. In study two, a total of 264 U.S. adults (115 women, 149 men) were again required to read vignettes, rate the target’s perceived partner quality, and report on the assumed pleasure and intimacy-focused motives of the target. The results of both studies revealed a reverse SDS, in which women were viewed as higher quality partners than men. Study two further demonstrated that women were assumed to have masturbated for both pleasure and intimacy-focused motives to a greater extent than men and that these motives helped to explain the reverse SDS. Overall, these findings highlight the need to equalize double standards in Western cultures to reduce potentially harmful effects on sexual health.

Keywords: Masturbation Sexual double standard Motives Perceived gender differences

---
General Discussion
In order to address the existing research gap surrounding masturbation in regard
to the SDS, the current body of research utilized experimental vignettes depicting
hypothetical men or women engaging in masturbation, assessed participants’
perceptions of the target’s partner quality in study one, and their perceived
motives in study two. Although recent research indicates conflicting results surrounding
the existence of a SDS, the current research provided replicated evidence
of a reverse SDS whereby the hypothetical men were judged as being
lower quality partners than the hypothetical women based on their lack of pleasure
and intimacy-focused motivations when masturbating.

Neutral Attitudes Toward Masturbation

The neutral judgments of hypothetical masturbators discovered in both studies provide
evidence that masturbation may not be as stigmatized as previously thought
(Kontula and Haavio-Mannila 2003). Additionally, as the number of people who
self-report engaging in masturbation has increased over the years, it is possible that
attitudes are growing increasingly more accepting toward this behavior (Kontula and
Haavio-Mannila 2003). This could partly be due to the increase in availability of
sexually explicit media, and the ways in which it can impact peoples’ perceptions
of sexuality and their masturbatory practices (Prause 2019). However, because of
the minimal research conducted in this area, it is difficult to determine the extent
to which attitudes toward masturbation have changed over the years. Regardless,
research assessing attitudes toward other sexual behaviors indicates that we are currently
living in an era in which Western cultural norms related to sexuality appear
to be shifting, with younger cohorts reporting more positive and accepting attitudes
toward sexual behavior than older cohorts (e.g., Twenge et al. 2015, 2016). Thus, the
neutral judgments discovered in study one and study two provide evidence that these
recent shifts may also apply to attitudes toward masturbation.

The Reverse Sexual Double Standard

Both study one and study two captured a reverse SDS regarding judgments of partner
quality, confirming the results from other recent research documenting a reverse
SDS with respect to other sexual behaviors (e.g., Papp et al. 2015; Sakaluk and
Milhausen 2012). As the SDS has become difficult to analyze (Jonason and Marks
2009; Milhausen and Herold 1999; Sprecher and Hatfield 1996; Thompson et al.
2018), it is important to note that the reverse SDS was replicated in the current body
of research. This reverse SDS may be due to a number of things, the first of which
being societal shifts in our perceptions of women’s sexuality due to social media
campaigns such as #MeToo and #TimesUp.

The second explanation for the reverse SDS may be related to the gendered media
portrayal of masturbation in Western cultures. For example, in a content analysis of
popular Western media, Madanikia and colleagues (2013) found evidence of negative
depictions of masturbation in scenes with which men were portrayed in comparison
to those with which women were portrayed. Consequently, if the media is a
true reflection of cultural attitudes surrounding specific behaviors, then it is possible
that we are being socially primed by consuming popular movies and television to
perceive men’s masturbation less favorably than women’s.

The third explanation for the reverse SDS is evident in the assumed motives for
masturbation. In particular, the results of study two revealed that perceived motives
contribute to the reverse SDS among hypothetical masturbators, in which women
were perceived as higher quality partners than men due to their assumed participation
for pleasure-focused and intimacy-focused motives. Pleasure-focused motives
were particularly important in accounting for the reverse SDS, which may be due
to the desirability of sexually agentic partners, and the impact they can have in the
context of relationships (Fetterolf and Sanchez 2015). In particular, it is possible
that sexual agentic women are perceived as more sexually aware and empowered,
thereby more desirable. This is consistent with existing research revealing that hypothetical
sexually agentic women (those describe as liking to “take the lead” during
sex) are perceived as more desirable than sexually passive women (those described
as liking their partner to “take the lead” during sex; Fetterolf and Sanchez 2015).
Further, hypothetical agentic women were even viewed as a more desirable sexual
partner than the hypothetical agentic men. Regardless of what caused these motives
to contribute to the reverse SDS, it is evident that perceived motives impacted participant’s
judgments, and that they likely influence the ways in which people engaging
in a variety of sexual behaviors are perceived.

In-marriage (e.g. consanguineous marriage) generates fractionalization because it yields relatively closed groups of related individuals and thereby encourages favoritism and corruption; out-marriage creates a relatively open society

Kinship, fractionalization and corruption. Mahsa Akbaria, DumanBahrami-RadbErik O.Kimbrough. Journal of Economic Behavior & Organization, Volume 166, October 2019, Pages 493-528. https://doi.org/10.1016/j.jebo.2019.07.015

Abstract: We examine the roots of variation in corruption across societies, and we argue that marriage practices and family structure are an important, overlooked determinant of corruption. By shaping patterns of relatedness and interaction, marriage practices influence the relative returns to norms of nepotism/favoritism versus norms of impartial cooperation. In-marriage (e.g. consanguineous marriage) generates fractionalization because it yields relatively closed groups of related individuals and thereby encourages favoritism and corruption. Out-marriage creates a relatively open society with increased interaction between non-relatives and strangers, thereby encouraging impartiality. We report a robust association between in-marriage practices and corruption both across countries and within countries. Instrumental variables estimates exploiting historical variation in preferred marriage practices and in exposure to the Catholic Church’s family policies provide evidence that the relationship could be causal.


Check also Schulz, Jonathan, Duman Barahmi-Rad, Jonathan Beauchamp, and Joseph Henrich. 2018. “The Origins of WEIRD Psychology.” PsyArXiv. June 22. https://www.bipartisanalliance.com/2018/06/populations-that-are-western-educated.html

How Empathic Concern Fuels Political Polarization

How Empathic Concern Fuels Political Polarization. Elizabeth N Simas, Scott Clifford, and Justin H Kirkland. Anerican Political Science Review, October 31 2019. https://doi.org/10.1017/S0003055419000534

Abstract: Over the past two decades, there has been a marked increase in partisan social polarization, leaving scholars in search of solutions to partisan conflict. The psychology of intergroup relations identifies empathy as one of the key mechanisms that reduces intergroup conflict, and some have suggested that a lack of empathy has contributed to partisan polarization. Yet, empathy may not always live up to this promise. We argue that, in practice, the experience of empathy is biased toward one’s ingroup and can actually exacerbate political polarization. First, using a large, national sample, we demonstrate that higher levels of dispositional empathic concern are associated with higher levels of affective polarization. Second, using an experimental design, we show that individuals high in empathic concern show greater partisan bias in evaluating contentious political events. Taken together, our results suggest that, contrary to popular views, higher levels of dispositional empathy actually facilitate partisan polarization.

Rolf Degen summarizing: Individuals high in empatic concern are prone to even greater political polarization and show greater partisan bias in the censorship of ideas and feelings of schadenfreude over others' misfortune.

Check also Schoenmueller, Verena and Netzer, Oded and Stahl, Florian, Polarized America: From Political Partisanship to Preference Partisanship (October 17, 2019). SSRN. https://www.bipartisanalliance.com/2019/11/brand-preferences-increasing.html

We conclude that many species possess the psychological processes to show some form of reciprocity; it might be a widespread phenomenon that varies in terms of strategies and mechanisms

Reciprocity: Different behavioural strategies, cognitive mechanisms and psychological processes. Manon K. Schweinfurth, Josep Call. Learning & Behavior, November 1 2019. https://link.springer.com/article/10.3758/s13420-019-00394-5

Abstract: Reciprocity is probably one of the most debated theories in evolutionary research. After more than 40 years of research, some scientists conclude that reciprocity is an almost uniquely human trait mainly because it is cognitively demanding. Others, however, conclude that reciprocity is widespread and of great importance to many species. Yet, it is unclear how these species reciprocate, given its apparent cognitive complexity. Therefore, our aim was to unravel the psychological processes underlying reciprocity. By bringing together findings from studies investigating different aspects of reciprocity, we show that reciprocity is a rich concept with different behavioural strategies and cognitive mechanisms that require very different psychological processes. We reviewed evidence from three textbook examples, i.e. the Norway rat, common vampire bat and brown capuchin monkey, and show that the species use different strategies and mechanisms to reciprocate. We continue by examining the psychological processes of reciprocity. We show that the cognitive load varies between different forms of reciprocity. Several factors can lower the memory demands of reciprocity such as distinctiveness of encounters, memory of details and network size. Furthermore, there are different information operation systems in place, which also vary in their cognitive load due to assessing the number of encounters and the quality and quantity of help. We conclude that many species possess the psychological processes to show some form of reciprocity. Hence, reciprocity might be a widespread phenomenon that varies in terms of strategies and mechanisms.

Keywords: Cooperation Reciprocity Cognition Emotion Norway rat Vampire bat Capuchin monkey

Introduction
The theory of natural selection predicts that only those behaviours evolve that increase the actor’s own survival and reproductive success (Darwin, 1859). Paradoxically, many species provide benefits to others, for instance, by providing care, food, information and support to con- and heterospecifics (Dugatkin, 1997). Cooperation is such a widespread phenomenon that we find evidence across the animal kingdom, ranging from bacteria (Crespi, 2001) to humans (Fehr & Fischbacher, 2003). The paradox of the evolution of cooperation was resolved for interactions between related individuals, i.e. by helping kin, shared genes are more likely to be transmitted to the next generations, which is in the interest of the helper (Hamilton, 1964). Still, the kin selection theory cannot explain the frequent occurrence of cooperation among unrelated individuals. Trivers (1971) offered a solution: reciprocal cooperation, i.e. helping those that were cooperative before. While several theoretical models have shown that cooperation can evolve via reciprocity (reviewed in Nowak, 2012), the theory has faced considerable resistance (e.g. Clutton-Brock, 2009; Connor, 2010; Hammerstein, 2003; Russell & Wright, 2009; Sánchez-Amaro & Amici, 2015; Stevens, Cushman, & Hauser, 2005; Stevens & Hauser, 2004, 2005; West, Griffin, & Gardner, 2007).
It is a central problem of the theory of reciprocity, and explaining cooperation more generally (especially among non-kin), that the extent to which behavioural exchanges are based on reciprocity is unknown. This problem is tightly linked to the cognitive underpinnings of reciprocity. Researchers, who assume reciprocity to be highly cognitively demanding, came to the conclusion that reciprocity is virtually absent in non-human animals (Amici et al., 2014; Clements & Stephens, 1995; Hauser, McAuliffe, & Blake, 2009; Pelé, Dufour, Thierry, & Call, 2009; Pelé, Thierry, Call, & Dufour, 2010; Sánchez-Amaro & Amici, 2015; Stephens, McLinn, & Stevens, 2002; Stevens et al., 2005; Stevens & Hauser, 2004). In contrast, researchers who assume that reciprocity varies in its cognitive load came to the opposite conclusion that reciprocity is widespread (Brosnan & de Waal, 2002; Brosnan, Salwiczek, & Bshary, 2010; Carter, 2014; Freidin, Carballo, & Bentosela, 2017; Melis & Semmann, 2010; Raihani & Bshary, 2011; Schino & Aureli, 2009, 2010b; Taborsky, Frommen, & Riehl, 2016). Here, we argue that the debate can be enriched and potentially resolved by identifying and discussing the concrete psychological processes of all different forms of reciprocity by using and incorporating findings from different lines of research. Although several authors have discussed the various mechanisms that may underlie reciprocal exchanges between individuals (e.g. Brosnan & de Waal, 2002; Schino & Aureli, 2010b), as far as we know, no attempt has been made to systematically relate those mechanisms to the psychological processes underlying them. Our aim in this article is to bring attention to this issue as a necessary step towards the ultimate goal of elucidating the psychological processes underlying different forms of reciprocity. Accordingly, our article is organised as follows: First, we summarise different behavioural strategies and cognitive mechanisms enabling reciprocity. Second, we apply this framework to three textbook examples of reciprocity, i.e. the Norway rat (Rattus norvegicus), the common vampire bat (Desmodus rotundus) and the brown capuchin monkey (Cebus apella). Third, we discuss the crucial behavioural, cognitive and emotional components enabling different forms of reciprocity. These psychological processes will allow us to draw clear predictions under which conditions reciprocity is likely to evolve. Finally, we provide concrete examples for prospective studies to better understand the evolutionary and psychological origins of reciprocity.

[...]

Three textbook examples of reciprocity

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Norway rat
Wild Norway rats live in large multi-female, multi-male colonies, which may be composed of more than 150 individuals (Davis, 1953). They frequently interact with related and unrelated colony members and form dominance hierarchies (Calhoun, 1979). They engage in various social behaviours like alarm calls, food sharing, huddling, social grooming and social play (reviewed in Schweinfurth, under review).
Norway rats have been repeatedly shown to reciprocate help in different paradigms (reviewed in Schweinfurth in press). The most commonly used paradigm is the food-exchange setup. Here one rat, i.e. the cooperating partner, provides food via a movable platform to the focal rat (cf. Rutte & Taborsky, 2007). After a delay of up to six days, the roles are exchanged and the focal rat can provide food to its previous partner (e.g. Stieger, Schweinfurth, & Taborsky, 2017). To ensure that food donations by the focal rats are based on the previous help by a partner, focal rats are always also tested with a defecting partner that did not provide food to them. Several controls have been conducted to ensure that, for instance, differential food intake, activity, copying, or other factors cannot explain their helping levels (for a discussion, see Dolivo, Rutte, & Taborsky, 2016; Schweinfurth & Taborsky, 2018b).
Rats help each other reciprocally according to at least two behavioural strategies. First, they help each other according to direct reciprocity. Female and male rats donate food to others reciprocally by providing more food to cooperating than defecting partners (Li & Wood, 2017; Rutte & Taborsky, 2008; Schneeberger, Dietz, & Taborsky, 2012; Schweinfurth, Aeschbacher, Santi, & Taborsky, 2019; Schweinfurth & Taborsky, 2016, 2017, 2018c; Simones, 2007; Viana, Gordo, Sucena, & Moita, 2010). In addition, female rats apply direct reciprocity when grooming each other (Schweinfurth, Stieger, & Taborsky, 2017). Such reciprocal allogrooming has significant fitness benefits, as reciprocal groomers live longer and suffer less mammary tumours in the lab (Yee, Cavigelli, Delgado, & McClintock, 2008). Finally, female rats also exchange allogrooming for food and vice versa (Schweinfurth & Taborsky, 2018b; Stieger et al., 2017). Besides direct reciprocity, female, but not male, rats engage in generalised reciprocity (Rutte & Taborsky, 2007, 2008; Schweinfurth et al., 2019). In a direct comparison, however, female rats donate over 20% more food to a partner with whom they have interacted, showing that direct reciprocity generates higher levels of cooperation than generalised reciprocity (Rutte & Taborsky, 2008).
What is the mechanism underlying reciprocity in Norway rats? First, hard-wired reciprocity cannot explain reciprocity among Norway rats because they tailor their help to the partner’s helping quality (Dolivo & Taborsky, 2015) and the partner’s need (Márquez, Rennie, Costa, & Moita, 2015; Schneeberger et al., 2012; Schneeberger, Röder, & Taborsky, submitted; Schweinfurth & Taborsky, 2018a). Furthermore, rats reciprocate help by using different actions (Schweinfurth & Taborsky, 2017) and different commodities (Schweinfurth & Taborsky, 2018b; Stieger et al., 2017), making a fixed response unlikely. Second, emotion-based reciprocity is also unlikely to explain reciprocity in Norway rats. They seem not to form social bonds even after being housed together for more than one and a half years (Schweinfurth, Neuenschwander, et al., 2017). They do not accumulate social information with their partners, but rather use the last experience (Schweinfurth & Taborsky, under review; Stieger et al., 2017). Third, there is no evidence for calculated reciprocity either. The amounts of received and immediate given help are not matched in male and female rats (Schweinfurth et al., 2019; Schweinfurth & Taborsky, under review). This is in line with their numerical ability being limited to six items, which is below the amount of grooming bouts they are known to reciprocate (cf. Davis & Bradford, 1986; Schweinfurth, Stieger, et al., 2017).
Reciprocity in Norway rats is probably best explained by attitudinal reciprocity (reviewed in Schweinfurth, in press). Rats form attitudes that are based on the last encounter with a partner (Schweinfurth & Taborsky, under review). Importantly, using the last encounters for reciprocity is not a result of memory interference as rats have been shown to memorise several partners (Kettler, Schweinfurth, & Taborsky, under review), several food preferences (Galef, Lee, & Whiskin, 2005) and several unique events (Panoz-Brown et al., 2016) despite a long time delay with potentially disruptive experiences. Importantly, attitudes are linked to received cooperation and not just the product of ‘feeling good’, as a study showed in which rats refused to reciprocate food donations that they received in the presence of, but not by, another rat (Schmid, Schneeberger, & Taborsky, 2017). Attitudes can be generalised to other partners because female rats show not only direct but also generalised reciprocity (Rutte & Taborsky, 2008). In addition, attitudes are not binary responses, like a cooperator or defector tag, but can be modulated by different values of help. For instance, rats groom a partner more often that has provided food to them than vice versa, suggesting that one food item is valued more than one allogrooming bout (Schweinfurth & Taborsky, 2018b). In addition, rats are more likely to provide oat flakes to a partner that provided them with banana pieces, i.e. highly preferred food, than with carrot pieces, i.e. less preferred food (Dolivo & Taborsky, 2015).


Common vampire bat
Vampire bats, which include three species, feed exclusively on the blood of other mammals (Dalquest, 1955). Common vampire bats live in small groups of eight to twelve individuals (Wilkinson, 1984). Such groups roost together in large colonies, ranging from a few individuals to over 2,000, whereby females often move between different roosts (Wilkinson, 1988). Groups usually consist of one male and its female harem or male bachelor groups (Wilkinson, 1985b, 1985a). Vampire bats are the only bats that regurgitate food to donate it to others (Carter & Wilkinson, 2013a). Besides food donations, vampire bats show high levels of allogrooming compared to other bats (Carter & Leffer, 2015). In addition, they adopt and nurse offspring of other colony members (Carter & Wilkinson, 2013a; Wilkinson, Carter, Bohn, & Adams, 2016).
Common vampire bats regurgitate blood to donate it to others. Early studies used numerous observations of these bats in their natural habitat and found that given and received help is correlated and reciprocated (Denault & McFarlane, 1995; Wilkinson, 1984). Recently, these findings have been replicated (Carter & Wilkinson, 2013c) and extended by several controlled experiments with captive bats (reviewed in Carter & Wilkinson, 2013b). In several experiments, individual focal bats were removed from their colony and fasted for one day. After the hungry focal individual was returned to its group, all food donations to this individual were recorded. The focal individuals received blood mostly from partners, which they had provided food before (Carter & Wilkinson, 2013c).
They mainly donate blood with conspecifics with which they roost together frequently but that do not necessarily belong to their group (Carter & Wilkinson, 2013b). Food donations are more common between females, which form stable social bonds, but males have also been shown to regurgitate blood for others in the laboratory (Carter & Wilkinson, 2013b). Such donations are highly valuable to recipients because vampire bats die within two to three days without a blood meal (Freitas, Welker, Millan, & Pinheiro, 2003; McNab, 1973). They reciprocate blood with both kin and non-kin, whereby donations are better explained by reciprocity than by relatedness (Carter & Wilkinson, 2013c). Extending the network to non-kin has been shown to be beneficial for the bats because when their main association partner was temporarily removed, those that had more associations with unrelated roost mates received more food donations (Carter, Farine, & Wilkinson, 2017; Carter & Wilkinson, 2015b). Besides exchanging blood, the bats also exchange allogrooming for food according to direct reciprocity (Carter & Wilkinson, 2013c; Wilkinson, 1986). In contrast, they seem not to use generalised reciprocity (Carter & Wilkinson, 2013c).
What is the mechanism underlying reciprocity in common vampire bats? First, hard-wired reciprocity cannot explain reciprocity since the bats exchange different services, like allogrooming with food (Carter & Wilkinson, 2013c). In addition, reciprocity is limited to few closely bonded individuals (Carter et al., 2017), which makes automatic responses to received help unlikely. Second, attitudes based on recent encounters seem to be unable to generate reciprocity because reciprocity can only be detected over long time frames or when socially bonded bats are observed in captivity (reviewed in Carter & Wilkinson, 2013b; Wilkinson et al., 2016). Third, calculated reciprocity is an unlikely explanation for their reciprocity. Like Norway rats, common vampire bats do not match the actual amount of received and given help (Carter & Wilkinson, 2013c), which makes reciprocity based on calculations unlikely. However, little is known about their cognitive capabilities that could elucidate the underlying cognitive processes that they use (for the only studies of examining cognitive skills, see Ratcliffe, Fenton, & Galef, 2003; Vrtilek, Carter, Patriquin, Page, & Ratcliffe, 2018).
Reciprocity in vampire bats is probably best explained by emotion-based reciprocity. Rather than considering the last encounters as Norway rats do, the bats reciprocate help over long time spans (see above). They form enduring social bonds with kin and non-kin, which can last over more than ten years (Carter et al., 2017; Carter & Wilkinson, 2013c, 2015b; Wilkinson, 1985b, 1985a, 1986). Importantly, their food-sharing network closely mirrors their social-bonding network (Carter & Wilkinson, 2013c). This suggests that social bonds play a crucial role in their decisions to help conspecifics. In line with this, the amounts of donated blood and grooming are linked to oxytocin levels, which suggests an emotional component in the decision to reciprocate (Carter & Wilkinson, 2015a).


Brown capuchin monkey
Brown capuchin monkeys, also called tufted or black-capped capuchin monkeys, live in colonies of up to 30 individuals (Carosi, Linn, & Visalberghi, 2005). They show a distinct linear hierarchy in both sexes (Janson, 1985). Further, their breeding system can be described as either one-male, multi-female or multi-male, multi-female (Carosi et al., 2005). These monkeys show various social behaviours, such as alarm calls, collaborative hunting, food sharing, social grooming and social play (Fragaszy, Visalberghi, & Fegan, 2009; Izawa, 1980).
Brown capuchin monkeys are probably the best-known example for reciprocity. Reciprocity has been demonstrated repeatedly by using various methods under controlled captive conditions. For instance, they donate food to others by handing over or dropping food close to a partner in an adjacent compartment, who will return the favour in the same way (de Waal, 2000; see de Waal, 1997, for a detailed ethogram of the donations). To ensure that food donations are a product of received help and partner directed, several control conditions have been conducted with partners of differing relationship quality or partners being absent (reviewed in de Waal & Brosnan, 2006). In addition to these active and passive food transfers, the monkeys also reciprocate food donations by using various less intuitive testing apparatuses, i.e. bar pulling, joysticks, lever boxes and token exchanges (Hattori, Kuroshima, & Fujita, 2005; Mendres & de Waal, 2000; Parrish, Brosnan, & Beran, 2015; Suchak & de Waal, 2012).
All the tests described above investigated direct reciprocity. In addition, capuchin monkeys show generalised reciprocity (Leimgruber et al., 2014). As far as we are aware, there has been no published report of indirect reciprocity in brown capuchin monkeys. However, they pay attention to third-party interactions and are inclined to accept exchange offers from humans that were observed to frequently reject such exchange requests from other monkeys (Anderson, Kuroshima, Takimoto, & Fujita, 2013). This might suggest indirect reciprocity, but further studies are needed that directly test this possibility.
What is the mechanism underlying reciprocity in brown capuchin monkeys? In contrast to Norway rats and common vampire bats, the mechanism of reciprocity among these monkeys is less obvious. The only mechanism that can be almost certainly excluded is hard-wired reciprocity. When the monkeys help each other, they consider the quality of received help (de Waal, 2000) and the quality of their relationship (Sabbatini, De Bortoli Vizioli, Visalberghi, & Schino, 2012). This makes a fixed response unlikely. Furthermore, calculated reciprocity seems unlikely but possible because two studies found that the amount of received and given help was correlated, which suggests memory and score keeping of previous helpful events to some degree (e.g. de Waal, 1997, 2000). In fact, capuchin monkeys have been shown to add items to a pool of non-visible items, suggesting that they can keep track of multiple food donations, which is needed for calculations (Beran, Evans, Leidghty, Harris, & Rice, 2008). However, not all studies found such a correlation between received and given help (Brosnan, Freeman, & de Waal, 2006; Sabbatini et al., 2012; Suchak & de Waal, 2012). Finally, studies set out to test for calculated reciprocity found no evidence (Amici et al., 2014; Pelé et al., 2010). It should be noted, however, that the monkeys in these studies did not pass the task-understanding condition. Therefore, additional studies on calculated reciprocity are needed.
There is less ambiguous evidence for the two remaining mechanisms underlying reciprocity. There is good evidence for attitudinal reciprocity (reviewed in Brosnan & de Waal, 2002; de Waal & Brosnan, 2006). In contrast to common vampire bats and in accordance with Norway rats, brown capuchin monkeys show short-term reciprocity (see above). Furthermore, they reciprocate help with familiar and unfamiliar partners (Suchak & de Waal, 2012), which suggests short-term attitudes rather than long-term bonds being the reason to help. However, there is also good evidence for emotion-based reciprocity. In a direct comparison, the monkeys were more likely to allow access to their food to a socially bonded individual than to an individual that provided food to them before (Sabbatini et al., 2012). This study suggests that the monkeys probably cooperate over long time frames and an emotional bond can become more important that attitudinal reciprocity in a partner choice situation. This is in line with observations from the wild that showed evidence for long-term reciprocity (di Bitetti, 1997; Izawa, 1980; Schino, di Giuseppe, & Visalberghi, 2009a; Schino, Di Giuseppe, & Visalberghi, 2009b; Tiddi, Aureli, Polizzi di Sorrentino, Janson, & Schino, 2011; Tiddi, Aureli, & Schino, 2012).
Hence, reciprocity in brown capuchin monkeys is probably a result of attitudinal reciprocity and emotion-based reciprocity. While attitudinal reciprocity cannot explain the selective helping of bonded individuals, emotion-based reciprocity cannot explain the repeatedly observed short-term reciprocity. Still, the results must not be contradictory, and both may explain some aspects of cooperation in these monkeys. For instance, Sabbatini et al. (2012) found that the same monkeys show short-term reciprocity in dyads, but long-term reciprocity in trios. This is an interesting finding because it suggests that individuals can possess multiple mechanisms to achieve reciprocity. The same may apply to other species, although this has not been studied extensively other than in humans.
Humans use different mechanisms to achieve different forms of reciprocity. People employ a calculated reciprocity approach with unfamiliar (Andreoni & Miller, 1993; Gachter & Falk, 2002) or business partners (Anderson, Hakansson, & Johanson, 1994; Steidlmeier, 1999). If, however, it gets difficult to memorise several events with a partner, people focus on the attitude towards partners based on the last encounter (Milinski & Wedekind, 1998). In contrast, we rarely use short-term reciprocity when interacting with friends; instead, we rely on emotional bonds based on long-term reciprocity (reviewed in Massen, Sterck, & de Vos, 2010; Silk, 2003). Overall, we help friends more than strangers (Gächter, Kessler, & Königstein, 2011) because we trust them (Buchan, Croson, & Dawes, 2002; Majolo et al., 2013) and expect them to return favours (Deutsch, 1975; Walker, 1995). Interestingly, donations towards strangers can be increased by applying oxytocin, which is associated with emotional bonds (Zak, Stanton, & Ahmadi, 2007). In addition, the more often strangers interact, the more trust is built up and the more they are treated like friends (Gächter et al., 2011). This suggests that we use multiple mechanisms that can transform into each other rather than being static.

Optimistic people live longer & better predicts mortality than income, including health and other controls; predicted trends show declining optimism (1976–95) for those with low education

Longer, more optimistic, lives: Historic optimism and life expectancy in the United States. Kelsey J. O'Connor, CarolGraham. Journal of Economic Behavior & Organization, November 2 2019. https://doi.org/10.1016/j.jebo.2019.10.018

Highlights
• Optimistic people live longer, based on nearly 50 years of longitudinal data (PSID).
• Optimism better predicts mortality than income, including health and other controls.
• Optimism changes over time and is positively associated with socio-economic status.
• Predicted trends show declining optimism (1976–95) for those with low education.
• Our findings illustrate the importance of tracking optimism in a systematic manner.

Abstract: How was optimism related to mortality before the rise in “deaths of despair” that began in the late 1990s? Using the Panel Study of Income Dynamics, we show that as early as 1968 more optimistic people lived longer. The relationship depends on many factors including gender, race, health, and education. We then evaluate these and other variables as correlates of individual optimism over the period 1968–1975. We find women and African Americans were less optimistic at the time than men and whites, although this changed beginning in the late 1970′s. Greater education is associated with greater optimism and so is having wealthy parents. We then predict optimism for the same individuals in subsequent years, thus generating our best guess as to how optimism changed for various demographic groups from 1976–1995. We find people with less than a high school degree had the greatest declines in optimism, a trend with long-run links to premature mortality and deaths of despair. Our findings highlight the importance of better understanding optimism's causes and consequences.

Keywords: MortalityOptimismExpectationsDeaths of despairDemographic trendsPrediction