Does a 7-day restriction on the use of social media improve cognitive functioning and emotional well-being? Results from a randomized controlled trial show no benefits from a severe screen-time reduction

Does a 7-day restriction on the use of social media improve cognitive functioning and emotional well-being? Results from a randomized controlled trial. Marloes M.C . van Wezel, Elger L. Abrahamse, Mariek M. P.  Van den Abeele. Addictive Behaviors Reports, June 15 2021, 100365. https://doi.org/10.1016/j.abrep.2021.100365

Highlights

• We compared a 10% vs. 50% reduction in social media screen time in a RCT.

• The intervention had no effect on multiple indicators of attention and wellbeing.

• Self-control, impulsivity and FoMO did not moderate the relationships.

• Participants reported improved attention, but behavioral attention did not improve.

• Overall, a more severe screen time reduction intervention does not appear more beneficial.

Abstract

Introduction: Screen time apps that allow smartphone users to manage their screen time are assumed to combat negative effects of smartphone use. This study explores whether a social media restriction, implemented via screen time apps, has a positive effect on emotional well-being and sustained attention performance.

Methods: A randomized controlled trial (N= 76) was performed, exploring whether a week-long 50% reduction in time spent on mobile Facebook, Instagram, Snapchat and YouTube is beneficial to attentional performance and well-being as compared to a 10% reduction.

Results: Unexpectedly, several participants in the control group pro-actively reduced their screen time significantly beyond the intended 10%, dismantling our intended screen time manipulation. Hence, we analyzed both the effect of the original manipulation (i.e. treatment-as-intended), and the effect of participants’ relative reduction in screen time irrespective of their condition (i.e. treatment-as-is). Neither analyses revealed an effect on the outcome measures. We also found no support for a moderating role of self-control, impulsivity or Fear of Missing Out. Interestingly, across all participants behavioral performance on sustained attention tasks remained stable over time, while perceived attentional performance improved. Participants also self-reported a decrease in negative emotions, but no increase in positive emotions.

Conclusion: We discuss the implications of our findings in light of recent debates about the impact of screen time and formulate suggestions for future research based on important limitations of the current study, revolving among others around appropriate control groups as well as the combined use of both subjective and objective (i.e., behavioral) measures.

Keywords: screen timescreen time interventionsustained attentioncognitive performanceemotional well-beingself-report bias

4. Discussion

In the past decade, we have witnessed an increase in studies focusing on the complex associations between the use of the smartphone and its (mobile) social media apps on the one hand, and attentional functioning (Rosen et al., 2013, Judd, 2014, Kushlev et al., 2016, Ward et al., 2017, Wei et al., 2012, Fitz et al., 2019, Marty-Dugas et al., 2018) as well as emotional well-being (Twenge and Campbell, 2019, Twenge et al., 2018, Twenge and Campbell, 2018, Escobar-Viera et al., 2018, Brailovskaia et al., 2020, Tromholt, 2016, Stieger and Lewetz, 2018, Aalbers et al., 2019, Frison and Eggermont, 2017) on the other hand. While research in this field is not without criticism, among others for its over-reliance on self-report data and cross-sectional survey methodologies, the concerns over the potential harm of mobile social media use have nonetheless given impetus to the development of screen time apps that can help people to protect themselves from harm by restricting their social media use. The current study explored the effects of such a social media screen time restriction on sustained attention and emotional well-being.

The findings show that, first of all, the intervention did not have the intended effect. Specifically, we implemented a 50% restriction in social media screen time for an experimental group, and compared this to a control group with a 10% restriction. Yet, this screen time manipulation failed mostly because participants in the control group reduced their social media app use on average with 38%, which was much more than the intended 10%. We deliberately opted to not include a 0% reduction control group in our design, in order to avoid Hawthorne(-like) effects (cf. Taylor, 2004, McCambridge et al., 2014) – hence, in order to provide also the control group participants with a full-blown sense of being involved in an experiment. The current finding that a non-zero percent reduction for a control group may trigger additional – and more problematic – side effects than the Hawthorne(-like) effects that we aimed to prevent with it, is an interesting finding in itself. It provides clear suggestions for optimal implementation of control groups in intervention studies of the current type, and deserves to be followed up as a target of investigation in itself. Indeed, some participants indicated that they felt uncomfortable when encountering a time limit. It is imaginable that participants reduced their screen time more than they needed to in order to avoid that situation. Alternatively, the failed manipulation may be due to a placebo effect (cf. Stewart-Williams & Podd, 2004). In this case, the mere expectation of receiving a social media reduction may have sufficed in promoting behavior change in the form of reduced social media use. Similar placebo effects were found in marketing research (Irmak, Block, & Fitzsimons, 2005).

To deal with the failed screen time manipulation, we provided analyses both for treatment-as-intended and treatment-as-is, with the latter set of analyses disregarding the intervention conditions but rather exploring linear associations between the degree of relative screen time reduction based on the data we obtained. Interestingly, neither analyses revealed a noticeable effect on the outcome measures. This finding suggests an alternative explanation for the lack of findings, namely that there may not be any negative association between social media screen time and the outcome measures to begin with. Indeed, the pre-test data – which are unaffected by the failed screen time manipulation – did not show any of the hypothesized correlations between social media screen time, emotional well-being and attentional performance. On the contrary, the only relationships found between social media screen time and the outcome measures ran counter to what one might expect: Heavier social media users reported experiencing less attentional lapses and negative emotions. The lack of any negative association between social media screen time and the outcome measures may explain why reducing this screen time has no causal impact: If social media screen time does not affect these outcomes much, altering it will unlikely cause much change in them.

This finding is interesting in light of recent debates in the field over the validity of screen time studies. A recurring concern voiced in these debates is that self-report measures of screen time are flawed to such an extent that their use can lead to biased interpretations (Kaye et al., 2020, Sewall et al., 2020). A key strength of the current study is that we used a behavioral measure of screen time. The fact that this measure shows no relationship to cognitive performance nor emotional well-being, calls into question the ‘moral panic’ over social media screen time (Orben, 2020).

An alternative explanation that should be mentioned here, is that despite the randomization of participants, the control and experimental group were not fully equivalent in terms of their smartphone behavior in the week prior to the experiment. The control group appeared to consist of heavier Instagram users whereas the experimental group consisted of heavier WhatsApp users. It is thinkable that this non-equivalence has had some influence on our findings. After all, for the light Instagram users in the experimental group, a 50% reduction in Instagram use may not have been very impactful, whereas for the heavy Instagram users in the control group, the actually enforced relative reduction of 35% may have had a more profound impact, thus leveling out any difference between the two groups. Future researchers thus need to carefully consider their experimental procedures to maximize the chances of equivalence between conditions.

While we believe that a strength of our current study is the use of actual smartphone data and performance based measures of attention, the paucity of the use of such measures in previous work prevented us from conducting an appropriate a priori power analysis, resulting in a sample size that may have been too small – as indeed indicated by for example the accidental but significant differences between conditions in terms of their baseline app use (see above). We hope that our study can serve to that purpose in the future.

While the manipulation did not resort an effect, the findings of our study did show that – disregarding of the condition they were in – people reported experiencing less cognitive errors and attentional lapses at the post-test. This is interesting, given that their actual attentional performances did not improve. Again, these findings are interesting in light over the recent debates over the use of self-report measures in research on the associations between screen time and psychological functioning. Recent studies show that the use of self-report measures leads to an artificial inflation of effect sizes of these associations (Sewall et al., 2020, Shaw et al., 2020), that self-reports of especially smartphone use are inaccurate (Boase and Ling, 2013, Ellis et al., 2019, Vanden Abeele et al., 2013), and that the discrepancies between self-reported and behavioral measures of smartphone use are themselves correlated with psychosocial functioning (Sewall et al., 2020). The mixed findings in research on the effects of screen time have led to a call for greater conceptual and methodological thoroughness (e.g., Whitlock and Masur, 2019, Kaye et al., 2020, Sewall et al., 2020, Shaw et al., 2020), with a specific call to prioritize behavioral measures over self-report measures. The discrepancy between the behavioral and self-report attention measures may be an artifact of this shortcoming of self-report methodology.

The null-results of FoMO, self-control and impulsivity as influential moderators should be elaborated on here. It was expected that a screen time intervention would negatively impact the emotional well-being of individuals, especially those high on FoMO, since reduced social media screen time also reduces the possibility to stay up-to-date. However, our results could not corroborate this notion. Several authors have suggested that rather than being a predictor of social media use, FoMO may be a consequence of such online behavior (e.g., Alutaybi, Al-thani, McAlaney & Ali, 2020; Buglass, Binder, Bets, & Underwood, 2017; Hunt et al., 2018). In the three-week intervention study of Hunt et al. (2018) for example, reduced social media use actually reduced feelings of FoMO. With our data, we could test this possibility. Hence, we executed a repeated measures ANOVA with FoMO as within-subjects factor and condition as between-subjects factor. This analysis revealed that the intervention had no significant effect on experienced FoMO (i.e., the experimental group did not experience larger changes in FoMO than the control group: F(1,74)= 0.09, p=.762). However, there was an effect of time on FoMO: at the post-test, FoMO was significantly lower than at the pre-test (Mdif = 0.18, F(1,74)= 6.65, p= .012). Perhaps this is indicative of an “intervention effect”, since our manipulation had failed and all participant significantly reduced their social media use during the intervention week.

Also, an overall finding of this study, which aligns with what prior research has found, was that participants were not able to estimate their screen time accurately: While participants’ actual screen time decreased during the intervention week, their self-reported screen time did not differ over time. Interestingly, participants did report a decrease in habitual use and problematic use. This may suggest that people may have a vague sense of their behavior (“I reduced my smartphone use”), but are unable to convert this adequately into numbers such as screen time in minutes. Alternatively, participants may have provided a socially desirable answer. Either case, our findings aligned with both recent and older studies showing that subjective screen time measures deviate from objective measures (e.g., Andrews et al., 2015, Boase and Ling, 2013, Vanden Abeele et al., 2013, Verbeij et al., 2021).

4.1. Limitations and Future Directions

This study is among the first to examine the effectiveness of a social media screen time reduction on sustained attention and emotional well-being. One of its strengths is the inclusion of behavioral measures, both for screen time and for sustained attention. The study is not without limitations, however. A number of methodological choices were made that significantly limit comparability with other findings in the field. The lack of a true control group (in which no intervention was implemented) and the limited sample size are major limitations to the current study. Future research should include more participants and should consider the use of a true control group, in which no intervention is implemented. Moreover, future research might look at different degrees of screen time reductions, ranging from no reduction to complete abstinence, to better address to what extent the magnitude of the restriction matters. To add, future work ought to consider how to account for individuals’ unique smartphone app repertoires. For instance, some individuals in our study were super users of mobile games rather than of social media. While this may lower generalizability, researchers might account for unique app repertoires by setting time restrictions on an individual’s top 5 apps, or on screen time in-total. Also, a one-week intervention is short. It is likely that a longer intervention is needed to produce an effect on the outcomes examined. Overall, a general observation that we make is that future research on screen time interventions needs to carefully question and compare (1) which types of interventions affect (2) which outcomes, (3) for whom and (4) under which conditions, and (5) because of which theoretical mechanisms.

An additional limitation is that, although they were kept blind about which condition they were in, participants were informed about what the experiment was about because willingness to set a restriction to one’s screen time was an important eligibility criterion; installing such a timer without the participants’ informed consent was deemed unethical. Given that the timers were installed on participants’ personal phones, it was easy for participants to look up what restriction was enforced on them. Future research might explore if participants can be kept in the blind. Perhaps this can be attained via the development of a screen time app tailored to this purpose. Notably, even though we found no increase in the use of social media on alternative devices, it should be acknowledged that social media can be accessed from other devices than smartphones alone, something that could be accounted for in future work. In this context, it is relevant to mention Meier and Reinecke’s (2020) taxonomy of computer-mediated communication. Meier and Reinecke advice researchers to carefully consider which level of analysis they are focusing on, most notably that of the device (i.e., a ‘channel-based’ approach) versus that of the functionality or interaction one has through the device. Decisions regarding the level of analysis are typically grounded in theoretical assumptions about the mechanisms explaining effects. We consider this observation relevant to researchers studying ‘digital detoxes’ or screen time interventions, as they similarly have to consider what it is exactly that they want participants to ‘detox’ from, the device, a particular app or functionality, or a type of interaction. Careful consideration of this issue is important, as it may be key to understanding why the extant research shows mixed evidence. In the current study we attempted to address the type of interaction people have with social media, targeting especially ‘passive social media use’ by enforcing only a partial restriction, but we only focused on mobile social media. Future researchers may wish consider more explicitly their level of analysis and how to operationalize it in an intervention.

Finally, as other research also shows (e.g., Ohme, Araujo, de Vreese, & Piotrowski, 2020), research designs that include behavioral measures of smartphone use are both ethically and methodologically challenging. In the current study, we only invited participants to the lab with smartphones running on recent versions of IoS or Android. However, some participants showed up unaware of the operating system of their phone. Others used older versions, on which the screen time monitoring features did not function, or had forgotten to activate the screen time monitoring feature prior to the baseline measurement (which we had also specified as an eligibility criterion). This led to exclusion of several participants. Additionally, in a pilot study of the experiment, we noticed that different phone brands and types use different interfaces to display screen time information. This led to confusion, for instance, over whether the displayed numbers were weekly or daily totals. Hence, to avoid errors, we chose not to let participants record their own screen time but rather explicitly asked participants to hand over their phone to a trained researcher who copied the information into a spreadsheet and installed the timers. Participants who felt uncomfortable with this procedure were invited to closely monitor the researcher, or – if desired – to navigate the interface themselves. Although only a handful of students chose this option, this shows that there are ethical implications to using data donation procedures that researchers have to consider.

To circumvent these issues in future studies, participants could be instructed to install the same app. However, this will increase the demands placed on participants. Participation in studies of this nature are already highly demanding and intensive, since participants have to undergo a multi-day intervention on behavior that is intrinsic to their daily lives, and with sharing of personal information. Additionally, asking participants to install a specific app that potentially remotely monitors their phone use can raise ethical concerns, especially when using a commercial app that makes profit of monitoring (and selling) user data.

Overall, it became clear that it is difficult to achieve the required sample size to investigate complex designs of this nature. Nonetheless, the contrasting findings in extant research call for more research on causal relations between social media use on the one hand, and emotional well-being and cognitive functioning on the other hand. This can only be achieved by the use of slow science and large resources.

Check also Reasons for Facebook Usage: Data From 46 Countries. Marta Kowal et al. Front. Psychol., April 30 2020. https://doi.org/10.3389/fpsyg.2020.00711

Sex Differences

Are there sex differences in Facebook usage? According to Clement (2019), 54% of Facebook users declare to be a woman. Research conducted by Lin and Lu (2011; Taiwan) showed that the key factors for men's Facebook usage are “usefulness” and “enjoyment.” Women, on the other hand, appear more susceptible to peer influence. This is concurrent with the findings of Muise et al. (2009; Canada), in which longer times spent on Facebook correlated with more frequent episodes of jealousy-related behaviors and feelings of envy among women, but not men. Similarly, in Denti et al. (2012), Swedish women who spent more time on Facebook reported feeling less happy and less content with their life; this relationship was not observed among men.

In general, women tend to have larger Facebook networks (Stefanone et al., 2010; USA), and engage in more Facebook activities than men do (McAndrew and Jeong, 2012; USA; but see Smock et al., 2011; USA, who reported that women use Facebook chat less frequently than men). Another study (Makashvili et al., 2013; Georgia) provided evidence that women exceed men in Facebook usage due to their stronger desire to maintain contact with friends and share photographs, while men more frequently use Facebook to pass time and build new relationships.

Effects of Evolution, Ecology, and Economy on Human Diet: Insights from Hunter-Gatherers and Other Small-Scale Societies

Effects of Evolution, Ecology, and Economy on Human Diet: Insights from Hunter-Gatherers and Other Small-Scale Societies. Herman Pontzer and Brian M. Wood. Annual Review of Nutrition  Volume 41, on-line June 17, 2021. https://doi.org/10.1146/annurev-nutr-111120-105520

Abstract: We review the evolutionary origins of the human diet and the effects of ecology economy on the dietary proportion of plants and animals. Humans eat more meat than other apes, a consequence of hunting and gathering, which arose ∼2.5 Mya with the genus Homo. Paleolithic diets likely included a balance of plant and animal foods and would have been remarkably variable across time and space. A plant/animal food balance of 40–60% prevails among contemporary warm-climate hunter-gatherers, but these proportions vary widely. Societies in cold climates, and those that depend more on fishing or pastoralism, tend to eat more meat. Warm-climate foragers, and groups that engage in some farming, tend to eat more plants. We present a case study of the wild food diet of the Hadza, a community of hunter-gatherers in northern Tanzania, whose diet is high in fiber, adequate in protein, and remarkably variable over monthly timescales.

Check also Although we are undoubtedly omnivores, we evolved quite early to become highly carnivorous and we continue to retain a biologic adaptation to carnivory:

Ben-Dor, Miki (2019) "How carnivorous are we? The implication for protein consumption," Journal of Evolution and Health: Vol. 3: Iss. 1, Article 10. https://www.bipartisanalliance.com/2019/03/although-we-are-undoubtedly-omnivores.html

Do Local Sex Ratios Approximate Subjective Partner Markets? There is a need for more fine-grained, age-specific sex ratios

Do Local Sex Ratios Approximate Subjective Partner Markets? Evidence from the German Family Panel. Andreas Filser & Richard Preetz. Human Nature, Jun 19 2021. https://link.springer.com/article/10.1007/s12110-021-09397-6

Abstract: Sex ratios have widely been recognized as an important link between demographic contexts and behavior because changes in the ratio shift sex-specific bargaining power in the partner market. Implicitly, the literature considers individual partner market experiences to be a function of local sex ratios. However, empirical evidence on the correspondence between subjective partner availability and local sex ratios is lacking so far. In this paper, we analyzed how closely a set of different local sex ratio measures correlates with subjective partner market experiences. Linking a longitudinal German survey to population data for different entities (states, counties, municipalities), we used multilevel logistic regression models to explore associations between singles’ subjective partner market experiences and various operationalizations of local sex ratios. Results suggest that local sex ratios correlated only weakly with subjective partner market experiences. Adult sex ratios based on broad age brackets, including those for lower-level entities, did not significantly predict whether individuals predominantly met individuals of their own sex. More fine-grained, age-specific sex ratios prove to be better predictors of subjective partner market experiences, in particular when age hypergamy patterns were incorporated. Nevertheless, the respective associations were only significant for selected measures. In a complementary analysis, we illustrate the validity of the subjective indicator as a predictor of relationship formation. In sum, our results suggest that subjective partner availability is not adequately represented by the broad adult sex ratio measures that are frequently used in the literature. Future research should be careful not to equate local sex ratios and conscious partner market experiences.

Discussion

Imbalanced sex ratios have been linked to a wide range of social consequences, including family formation, economic decision-making, gender roles, partnership formation, fertility, personality, and sexuality (Bauer & Kneip, 2013; Feingold, 2011; Griskevicius et al., 2012; Harknett, 2008; Merli & Hertog, 2010; Pollet & Nettle, 2008; Schacht & Smith, 2017; Trent & South, 2012; Uggla & Mace, 2017). Sociodemographic and evolutionary mating market approaches have explained these findings by shifts in bargaining power based on differential mating opportunities for men and women in an imbalanced sex ratio environment (Filser & Schnettler, 2019; Guttentag & Secord, 1983; Kokko & Jennions, 2008; Pedersen, 1991; Schacht & Kramer, 2016). Individual partner market experiences might play a crucial role in these behavioral adaptations to local sex ratios given that subjective experiences provide critical guidelines for human behavior (Gilbert et al., 2016; Gintis, 2006; Kroneberg & Kalter, 2012). Yet, empirical evidence has been lacking on how closely individual experiences of partner market opportunities correspond to sex ratios of their local environment. To fill this gap, we analyzed associations between a variety of local sex ratio measures and subjective partner market experiences of female and male singles in a German panel survey.

In sum, the expected association between subjective partner market experiences and local sex ratios only held for selected, age-specific sex ratio measures. In particular, adult sex ratios based on broad age ranges as are commonly used in the literature did not prove to be significant predictors of subjective partner market experiences. This result was consistent across operationalizations of adult sex ratios as the proportion of men in the adult population (PMA) based on different age brackets at the level of states, counties, and municipalities. None of the adult sex ratio variants correlated with either men’s or women’s subjective experiences of surplus encounters with individuals of their own sex in a meaningful way. More granular, age-specific sex ratio measures (ASPM) that include only individuals of adjacent age cohorts were closer approximations of subjective partner market experiences. In particular, age-specific measures that also incorporated age shifts to reflect age hypergamy patterns proved to be better predictors of subjective partner market experiences. Nevertheless, only selected state-level, age-shifted sex ratios correlated with women’s surplus encounters with other women in a statistically significant way. The corresponding county-level age-shifted sex ratios yielded similar, yet smaller coefficients, which have to be interpreted with caution given that they did not reach statistical significance. For men, only county-level, age-shifted sex ratios significantly predicted associations with men’s subjective partner market experiences. Coefficients for state-level age-shifted sex ratios were similar in size but did not reach statistical significance. Overall, some reservations regarding the state-level findings seem warranted because the German states might be too large in geographic terms (with all but four being larger than 15,000 km2) to be considered a single partner market. Lengerer (2001:142) reports that 85% of future partners in Germany live within a 20 km radius of each other. Recent publications suggest that earlier recommendations to rely on smaller entities when operationalizing local partner markets continue to apply in the age of Internet dating (Bruch & Newman, 2019; Fossett & Kiecolt, 1991). Therefore, results for state-level sex ratios should be treated with caution.

In sum, the results of this study suggest that previous findings regarding the social consequences of imbalanced sex ratios are unlikely to be mediated by conscious adaptations to partner scarcities or oversupplies. Adult sex ratios for fixed age brackets, such as the population aged 16–49 or 16–64, constitute the standard operationalization of local sex ratios in the literature (see Schacht et al., 2014; Pollet et al., 2017 for reviews). Our findings suggest that sex ratios for fixed adult age ranges are unlikely to correspond closely to subjective partner market experiences. Previous research has demonstrated that sex ratios correlate only moderately with each other when different age cutoffs are used (see Fossett & Kiecolt, 1991 for a discussion using US census data). Therefore, adult sex ratios are unlikely to be a well-suited summary measure of age-specific sex ratios. This is also supported by our dissimilar results for adult and age-specific sex ratios. In contrast to adult ratios, selected age-specific and age-shifted operationalizations significantly predicted subjective partner market experiences. In particular, the integration of age hypergamy into the sex ratio measures yielded significant results for predicting subjective partner market experiences. Future research should therefore consider focusing on age-specific, age-shifted sex ratio measures. Yet, although age-shifted sex ratios predicted men’s subjective partner market experiences, we only find weak evidence for a similar association for women. This difference between men and women might be due to a smaller sample size of women in our models. A further explanation could be related to sex differences in sexual strategies guiding partner market behavior. In particular, sexual strategies theory suggests that sexual selection favored antagonistic mating competition and preferences for multiple short-term mating in men (Buss, 1999; Schmitt, 2015; Trivers, 1972). This could also entail that men are more aware of marriage squeezes than women are.

A further finding of this paper is that subjective surpluses of same-sex encounters significantly predicted relationship formation. For both sexes, a subjective surplus of encounters with individuals of one’s own sex was significantly associated with a lower probability of entering a relationship. We are aware that survey questions on subjective partner market experiences may represent an excessive demand for respondents. However, the fact that the subjective indicator correlates with this specific partner market outcome supports the idea that the analyzed reports of surplus encounters with same-sex individuals constituted a valid approximation of individual partner market experiences. Concerning the local sex ratio measures, age-specific and age-shifted variants proved to be advantageous over adult sex ratios also when predicting relationship formation. None of the adult sex ratios significantly predicted relationship formation. Moreover, age-specific local sex ratios only yielded significant coefficients when incorporating age shifts. Specifically, relationship formation for women was significantly predicted by state- and county-level age-specific and age-shifted sex ratios. Yet, the probability of men entering a relationship was not predicted by local sex ratios, replicating similar asymmetric findings by Uggla and Mace (2017). With regard to the link to subjective partner market experiences, our findings suggest that subjective partner market experiences and local sex ratios should be considered distinct context variables rather than equivalent indicators. This is even true for detailed measures of local sex ratios. For instance, age-specific county-level sex ratios with a two-year age shift were a significant predictor of women’s relationship formation. Yet, we do not find conclusive evidence that these measures were correlated with women’s subjective partner market experiences. Consequently, these findings suggest that subjective and local sex ratios are not interchangeable operationalizations. Rather, they appear to be two separate dimensions of partner market circumstances. Researchers should be aware of this distinction when offering theoretical interpretations of results based on local sex ratios.

The subjective partner market indicator used in this study is not equivalent to the situational perception of the sex proportions in a group. Instead, it approximated the everyday interactions of individuals and therefore should not be interpreted as indicative of an inability to perceive sex ratios in set groups. Both Alt et al. (2017) and Neuhoff (2017) demonstrated that participants are able to give accurate sex ratio estimations based on short-term exposure to visual and auditory cues. Against the backdrop of these previous studies, one potential explanation for our findings could be that individual partner market experiences are not a direct representation of macro-structural conditions, i.e., local sex ratios (Blau, 1977; Rapp et al., 2015; Schwartz, 1990). Instead, individual partner markets may be structured in different “foci of activity,” such as workplaces, voluntary associations, or hangouts (Feld, 1981; Rapp et al., 2015). With this in mind, studying the consequences of sex ratios in interactive spheres such as workplaces (Åberg, 2009; Barclay, 2013; Svarer, 2007), industries (Uggla & Andersson, 2018), bars (Lycett & Dunbar, 2000), or colleges (Harknett & Cranney, 2017) would have the advantage of assuming that the individuals are actually interacting with one another. This is much more plausible than the same contention would be for local sex ratios. Consequently, individuals’ foci-specific sex ratios might give a more accurate impression of partner supply and demand within the respective foci rather than sex ratios of the local population, even for their specific age cohort.

This paper used a combination of administrative population information and survey data, which is crucial to this analysis. Studies relying on such data face a trade-off between the scope of the data and the ability to link survey data with survey-based partner market measures. The pairfam survey data constitute a unique combination of both ends of this spectrum. However, adult sex ratios in Germany may not have sufficient variation to allow for identifying a clear effect. This is particularly true for adult sex ratios at the state level, which only range between 96 and 108 men per 100 women (see Table 2). Consequently, nonsignificant findings for state-level sex ratios could also be due to the lack of variation at this level of aggregation. Internationally, local adult sex ratios may vary more substantially in selected regions, most notably in the male-skewed populations of China and India (Guilmoto, 2012). However, the county-level variation in adult sex ratios in the analyzed data was consistent with that of recent studies from other Western countries (e.g., Schacht & Kramer, 2016), and the ranges of age-specific sex ratios exceeded the ranges of adult sex ratios in our data.

A further limitation is that the findings are contingent on the validity of the subjective partner market indicator. While our complementary analysis demonstrated the predictive validity of the subjective indicator with respect to relationship formation, limitations persist. The directional verbalization of the indicator question introduced ambiguity, resulting in imprecise measurement of undecided and disagreeing answers. Specifically, respondents who met an equal number of men and women either might have reported disagreeing with the statement of predominantly meeting individuals of their own sex or might have given an undecided answer to express their experience of a balanced sex ratio. We explored this issue via fitting linear and multinomial models for different variants of the original indicator scale. These auxiliary results confirmed that the difference in probabilities for undecided and disagreeing answers was not significantly correlated to local sex ratios. However, agreement with the surplus same-sex contacts scale was related to selected local sex ratio measures (Fig. S6-S8, in the ESM). We therefore focused on the dichotomized indicator that summarized disagreeing and undecided responses. Nevertheless, our logistic regression results do not persist when taking a linear modeling approach, most likely because of measurement noise in disagreeing and undecided responses. Furthermore, the current analysis was limited to one global subjective indicator of opposite-sex encounters. A detailed survey of foci-specific sex ratios might give a closer approximation of subjective partner market experiences (cf. Rapp et al., 2015). This could reveal whether partner markets in specific foci actually correspond to local sex ratios, whereas partner markets in other foci do not. In particular, detailed information on job location could be of particular relevance, given that 60% of German employees cross municipality borders when commuting (Pütz, 2017). Consequently, adding sex ratios based on the place of work could yield a higher correspondence to subjective partner markets.

In conclusion, the sex ratio literature should be cautious regarding the assumption that individuals are consciously aware of local sex ratio skews. In particular, subjective and conscious partner market experiences do not appear to be a direct function of broad-range adult sex ratios but instead are correlated only with selected, age-specific measures. Researchers should consider this when interpreting findings based on local sex ratios. Although our findings shed some doubt on a direct link between conscious experiences and local sex ratios, this does not necessarily imply that local sex ratios do not capture partner markets. So far, very little is understood about how humans experience, remember, and process contextual sex ratios (Dillon et al., 2017). In particular, the relative importance of immediate interaction partners, local communities, and broader social contexts is yet to be explored (Maner & Ackerman, 2020).

This paper explored the relationship between a general indicator of subjective partner market experiences and local sex ratio measures. In sum, general sex ratio measures that are based on broad age ranges do not seem to capture conscious partner market experiences in a meaningful way. Future research will have to establish the role of unconscious factors, including endocrinal or network effects mediating contextual local sex ratios and adaptations in individual behavior.

People often complain that their romantic partner spends money foolishly; & tightwads (who find spending money very painful) and spendthrifts tend to attract, which leads to arguments and financial infidelity

“You Spent How Much?” Toward an Understanding of How Romantic Partners Respond to Each Other’s Financial Decisions. Jenny G. Olson, Scott I. Rick. Current Opinion in Psychology, June 21 2021. https://doi.org/10.1016/j.copsyc.2021.06.006

Abstract: How people choose to spend money is often observable to others (e.g., based on their clothes, accessories, and social media pages), but there is a whole universe of financial decisions that are essentially unobservable (e.g., how people handle their debts, taxes, and retirement planning). We explore one context where people have an up-close-and-personal view of someone else’s financial decision-making process: romantic relationships. We discuss how the endless opportunities for financial observation in romantic relationships influence a range of behaviors, including spending habits, decisions about bank account structure, and financial infidelity. Our review highlights the need for more research on the ways in which financial decisions are made, communicated, and observed within romantic relationships.

Keywords: consumer financial decision-makingromantic relationshipsmarriageperson perception

Higher levels of men’s family carework were associated with lower suicide mortality, especially among men and under high-unemployment conditions, wich points to the suicide-protective potential of men’s family carework

Caregiving as suicide-prevention: an ecological 20-country study of the association between men’s family carework, unemployment, and suicide. Ying-Yeh Chen, ZiYi Cai, Qingsong Chang, Silvia Sara Canetto & Paul S. F. Yip. Social Psychiatry and Psychiatric Epidemiology, May 5 2021. https://doi.org/10.1007/s00127-021-02095-9

Abstract

Purpose: Suicide rates are generally higher in men than in women. Men’s higher suicide mortality is often attributed to public-life adversities, such as unemployment. Building on the theory that men’s suicide vulnerability is also related to their private-life behaviors, particularly men’s low engagement in family carework, this ecological study explored the association between men’s family carework, unemployment, and suicide.

Methods: Family-carework data for twenty Organization for Economic Co-operation and Development (OECD) countries were obtained from the OECD Family Database. Sex-specific age-standardized suicide rates came from the Global Burden of Disease dataset. The association between men’s engagement in family carework and suicide rates by sex was estimated, with OECD’s unemployment-benefits index and United-Nations’ Human Development-Index (HDI) evaluated as controls. The moderation of men’s carework on the unemployment-suicide relationship was also assessed.

Results: Overall and sex-specific suicide rates were lower in countries where men reported more family carework. In these countries, higher unemployment rates were not associated with higher male suicide rates. In countries where men reported less family carework, higher unemployment was associated with higher male suicide rates, independent of country’s HDI. Unemployment benefits were not associated with suicide rates. Men’s family carework moderated the association between unemployment and suicide rates.

Conclusion: This study’s findings that higher levels of men’s family carework were associated with lower suicide mortality, especially among men and under high-unemployment conditions, point to the suicide-protective potential of men’s family carework. They are consistent with evidence that where gender equality is greater, men’s and women’s well-being, health, and longevity are greater.

55 traditional cultures: Experts with observable motor skills like toolmaking were often generous teachers, but specialists with conceptual know-how for uncommon problems (health) used secretive knowledge to help clients

Ethnoscientific expertise and knowledge specialisation in 55 traditional cultures. Aaron D. Lightner, Cynthiann Heckelsmiller and Edward H. Hagen. Evolutionary Human Sciences, accepted manuscript, pp. 1 - 52, Jun 14 2021. https://doi.org/10.1017/ehs.2021.31

Abstract: People everywhere acquire high levels of conceptual knowledge about their social and natural worlds, which we refer to as ethnoscientific expertise. Evolutionary explanations for expertise are still widely debated. We analysed ethnographic text records (N=547) describing ethnoscientific expertise among 55 cultures in the Human Relations Area Files to investigate the mutually compatible roles of collaboration, proprietary knowledge, cultural transmission, honest signalling, and mate provisioning. We found relatively high levels of evidence for collaboration, proprietary knowledge, and cultural transmission, and lower levels of evidence for honest signalling and mate provisioning. In our exploratory analyses, we found that whether expertise involved proprietary vs. transmitted knowledge depended on the domain of expertise. Specifically, medicinal knowledge was positively associated with secretive and specialised knowledge for resolving uncommon and serious problems, i.e., proprietary knowledge. Motor skill-related expertise, such as subsistence and technological skills, was positively associated with broadly competent and generous teachers, i.e., cultural transmission. We also found that collaborative expertise was central to both of these models, and was generally important across different knowledge and skill domains.

Social media summary: In a cross-cultural study we found that experts with observable motor skills like toolmaking were often teachers, but specialists with conceptual know-how for uncommon problems like illness used secretive knowledge to help clients.

Keywords: Ethnoscience, Expertise, Cultural transmission, Conceptual knowledge, eHRAF

Animals also hold beliefs and there are some aspects that underly the formation of beliefs which are shared with other animal species, namely the relationship between causality, predictability and utility of beliefs

An Evolutionary Approach to the Adaptive Value of Belief. Anabela Pinto. Chapter in Evolutionary Psychology Meets Social Neuroscience, June 14th 2021. DOI: 10.5772/intechopen.97538

Abstract: The word “belief” evokes concepts such as religious or political beliefs, however there is more to belief than cultural aspects. The formation of beliefs depends on information acquired through subjective sampling and informants. Recent developments in the study of animal cognition suggest that animals also hold beliefs and there are some aspects that underly the formation of beliefs which are shared with other animal species, namely the relationship between causality, predictability and utility of beliefs. This review explores the biological roots of belief formation and suggests explanations for how evolution shaped the mind to harbour complex concepts based on linguistic structures held by humans. Furthermore, it suggests that beliefs are shaped by the type and process of information acquisition which progresses through three levels of complexity.

Keywords: Biology of beliefutility of beliefsacquisition of information meaning causality predictability utility bias

5. The adaptive value of beliefs

Thinkers, scientists and philosophers reach their own conclusions through methodological approaches specific to their field of expertise. In the process, they innovate, discover new methodologies, suggest theories. In summary, they gain insights into the problems they are addressing. When creating testable hypotheses, they make assumptions held as true, testing them for inconsistencies, flaws, mistakes, illogicality, etc. Hopefully, after a certain amount of time and painstaking testing, some of these assumptions, become a ‘truth’ in the mind of the thinker and her followers even though it is only a hypothesis. This truth will only survive until new evidence refutes it. A new paradigm replaces the former and the cycle restarts. This paradigm shift was thoroughly discussed by the American philosopher and physicist Thomas Kuhn in his 1962 book The Structure of Scientific Revolutions.

Many of our present social and personal beliefs result from cultural inheritance, our reliance on other people and sources we trust. Our survival depends on a large number of “specialised believers” telling us what to think.

We believe in the insights of others that preceded us and adopt them as truths. The teachings of the Buddha and the Middle Eastern religions, the insights of Classical Greek philosophers about the mind and nature, the discoveries of the Enlightenment and the progress of the industrial revolution, all are examples of personal insights that spread in space and time. Some insights are independently arrived at in different cultures and time frames, their common aspects suggesting that they may be intuitive across humankind. Similar social norms and recommendations based on an awareness of human nature that ensure that social order is upheld are found in tribal societies that never had contact with each other. Some of these rules have deep roots in biology, such as those aimed at controlling female behaviour to ensure the paternity of the offspring. Many of these norms passed on from generation to generation become enshrined in our present cultural norms and are still held as unquestionable dogmas. Similarly, questioning religious and scientific dogmas is still frowned upon by members of the groups that hold such doctrines. Individuals become emotionally attached to such beliefs and express anxiety and defensive reactions when such beliefs are challenged. This begs the question by which processes do beliefs operate to induce such strong emotional attachment?

There are aspects of the content of the belief that tap deeply into our biology [1]. When the information content of a belief aligns in some way with processes that provide survival strategies, that information perceived as meaningful is ardently protected and any challenge to its truth is aggressively repelled.

Which attributes make up the mind is much debated; however, their common features include the integration of a sensorial mechanism which contributes to make sense of an individual’s external and internal world. Whether or not the individual is conscious of that sense or meaning is irrelevant to definition, since proving presence of awareness in most animals empirically is impossible due its subjective nature. In the Descent of Man, Darwin laid out the case for believing that the difference between the minds of humans and other animals was ‘certainly one of degree and not of kind’.

There are at least four basic conditions that make a belief meaningful. First the belief must offer an explanation for causal events, secondly it must offer a sense of predictability, thirdly, the information received must be reliable and correspond to what is believed to be fact and finally, that belief must have some utility providing survival advantages [40]. But before each one of these conditions is addressed, it is necessary to understand the notion of meaning.

5.1 A biological approach to the concept of meaning

The concept of meaning can be approached through a philosophical point of view such as ‘what is the meaning of life’, a psychological cognitive approach, such as ‘what you are telling me makes no sense in my mind’ and through a linguistic approach which begs for definitions such as in ‘what is the meaning of this word?’. The linguistic description of meaning plays an important role in communication and spread of beliefs. A sound, a word, a sentence, all have meaning when they contribute to the comprehension of the message. But comprehension or understanding is also a function of the subjective experiences of the receiver. If I say “table” it induces different mental images in the receiver. It can be a word that simply categorises objects with four legs and a surface high enough to allow our legs under it. But there are many variations of the concept table. Is it in wood or metal and glass? Is it unassuming with straight lines or convolutedly decorated with arabesques? The word table may confer a limited number of characteristics that are common to most people that have experienced the shape and function of furniture but its meaning varies accordingly to function. Is it a dining table, a coffee table or a desk? Whereas descriptive words for objects may be easy to define by just pointing at it or simply describing its function, abstract concepts may have different meanings to different people. For example, what is the meaning of the concept of freedom of speech? Does it mean I can say whatever I feel like or does it encompass a certain level of censorship to prevent incitement to harm others? What is the meaning of friendship? Does it require unconditional loyalty or does it give room for compassionate lies?

Frequently, what gives meaning to some of these abstract concepts is the level of emotion associated with them. People who believe in freedom, or God, or homoeopathy may feel threatened when their beliefs are challenged because such beliefs define the individual, her nature, his cultural identification, her expectations. Holding strongly to beliefs provides a sense of security and predictability. Such emotions are defined by neurological processes that transduce the sound of words, to their meaning and to their emotional valence; e.g. whereas to some people the word spider evokes fear and the word mouse evokes of cuteness, to others the word mouse may evoke feelings of fear and anxiety. A thing has meaning when its description aligns with our preconceived mental models. If I am learning statistics, a t-test only has meaning if I have a prior knowledge of means and other arithmetic calculations. Asking someone to do a t-test on a set of numbers without previous understating of basic concepts, renders the requirement meaningless. Furthermore, it may induce a state of anxiety due to acknowledgement of ignorance about that subject.

The informational content of a message acquires meaning, when it is compared with a mental database of previously learnt units of knowledge and it aligns or provides incremental increases to that knowledge. It follows that meaningful information is more useful than meaningless information. It functions as a tool of survival, based on which we can induce and deduce further knowledge. It is therefore reasonable to assume that an emotional connection between pieces of meaningful information is formed. On the other hand, meaningless information triggers a sense of discomfort and rejection. Meaningful information comes associated with an emotional protective layer to challenge. This explains the strong tendency to confirmation bias and rejection of new sources of knowledge that disconfirms our beliefs.

Individuals develop an emotional attachment to familiar information to the point of suffering great anxiety when that information is deemed false.

Festinger [41] defined meaning as the perception of coherence between one’s beliefs and the real world. “When these things align, we are left with the sense that the world is ordered, controlled, and understandable. When this coherence is disrupted, however, meaning is threatened and we feel distressed and anxious as a result”.

The sense of meaning could then be seen as an adaptive feature derived and supporting beliefs. Adaptive beliefs are those which contain information that contribute to individual survival. A belief is adaptive if the information about what caused an event is reliable, predictable and useful. Beliefs shaped in this context are very likely to be strong which means, they are upheld in the mind with vehemency and any challenge to the belief is perceived as a threat to constancy. Some mental processes are common across species because they are built on neural structures that have roots in common ancestors. Perhaps the most primitive processes are those that refer to identifying the causes of what happens around oneself. The next step consists in an ability to predict future events and prediction can only be successful if it relies on the accuracy and reliability of previously stored information.

5.2 Causality: understanding causes and sequences of events

As discussed above the establishment of associations between cause and effect is perhaps the most ancient form of learning. Such associations provide the organisms with opportunities to test and improve its tactics during the acquisition of resources essential for their survival. Beliefs about the cause of events are perhaps one of the most important factors for survival. When we know what caused an event, we can somehow predict the outcome next time a similar cause is enacted. The concept of causality is coupled with the perception of agency. An agent is a living or inanimate cause which triggers an event, but very often humans attribute intentionality to the agent.

Detection of the cause-effect association is quite powerful and the motivation to find an explanation for the cause sometimes disregards rational thinking. If the explanation satisfies, then it is likely to be promptly accepted as true.

Explanation of causes are often associated with the presence of an agent. In humans, when the cause is unknown because there is no direct observation of the causal event, there is a tendency to create an invisible agent and attribute human characteristics such as intentionality. This is an important component of magical thinking and is the origin of animistic religions which created a backcloth to religions with deities. Animism attributes intentionality to forces of nature without anthropomorphic representations of entities. In animism, the believer appeals to the forces and energy of nature. They refer to the spirit of the elements such as the wind, the water, the earth as if they were fuzzy undelimited agents with consciousness and aims. Religion with gods is built on this principle where the agent is no more the forces of nature, but some invisible figure that concentrates those forces. These agents can be represented as animals whose characteristics identify with the natural phenomenon or humans.

The assumption that we are hardwired to discern relationship between cause and effect induces us to pay more attention to events that coincide, or are salient especially when they support our beliefs, thus reinforcing confirmation bias and often supporting beliefs in the paranormal.

5.3 Predictability

Assuming predictability is a strategy for coping with uncertainty. It helps in planning future decision making. Uncertainty leads to anxiety and stress and, as such, beliefs that promote a false impression of predictability are naturally easier to accept. Observations of animal behaviour and historical narratives have shown evidence that safe environments promote co-operation and trust among the members of a social group, whereas instance of resource shortage and unpredictable social settings are conducive of social instability often expressed in varied forms of aggression [1].

Predictability is intrinsically associated with pattern detection. The perception of patterns, even when they are absent in reality, confers a sense of control. Patternicity equates constancy and repeatability [1].

The perception of patterns and the need for predictability underpin the onset of superstitious behaviours present in humans and animals [42]. A pursuit of predictability is yet more pronounced in situations marked by environmental social instability. For example, studies on political preferences suggested that the way humans perceive insecurity and unpredictable events may have some influence on their political beliefs. Research revealed that helping people imagine they are completely safe from harm can make them (temporarily) hold more liberal views on social issues [43, 44] and that a perception of threat can make liberals lean more towards conservative views [45].

When the information is provided by an informant rather than through subjective sampling, the reliability of the message can vary in levels of accuracy since many factors may corrupt the informational content from the time it leaves the informant and arrives at the receiver. The type and intensity of these modifications affect the reliability of the message and may therefore provide misleading information. The occurrence of ambiguity in the message is frequently interpreted as satisfying the desired goals inducing a belief that the message offers predictions that satisfy their expectations. This process is open to behaviour manipulation. Corrupted informational content may be unintentional, deriving from random mistakes or misperception, but can also be intentional where the informer sends purposefully dishonest signals. Since dishonest signalling is widespread in nature, detection systems have co-evolved to counteract such signals.

Conveying truthful and fake information are processes that promote the survival of individuals but are not without trade-offs. While cheating can be advantageous to individuals that interact only once, it will work against the cheater once the interaction is repeated and detected. Then cheating does not pay anymore. In social groups where most individuals know one another, the cheater may collect immediate rewards but once it is detected, it is promptly punished by elements of the group. However, in human social groups when the cheating is propagated through words that meet the desires and expectations of the receivers, the cheater can get away with his lies for quite a long time. Humans seem to be open to accept lies, as long as they align with their wishful thinking. In evolutionary terms this seems to be a process that would eventually vanish from the population, given its negative impact. However, it is not all negative, for there is also a need to conform with the beliefs of the group as a means of gaining protection.

5.4 Utility

Group membership in mammals is usually established by sharing similar scents. In humans, scent identification is complemented by the sharing similar ideas where thinking like the tribe becomes the equivalent of smelling like the tribe and fitting in the same social group. Similar scents indicate a level of kin relations and, accordingly to kin selection theory based on mathematical models developed by George R. Price [46] and popularised by W.D.Hamilton [47], altruism and cooperation are more prevalent among individuals that share the highest number of genes. This implies that individuals are more likely to protect those who share genes with them, than those who do not.

Likewise, in human societies this rule could be applied to ideas in the sense that those individuals that share the same stances as me are more likely to protect one another. These ideas were popularised by Richard Dawkins [48] who coined the word memes, suggesting that the transmission of information from mind to mind follows similar rules like the transmission of molecular information through genes from parents to offspring.

This convergence towards homogenous ideas inside the group may explain the success of religion, political factions, belief in conspiracy theories, doomsday and other cults, reflecting a process of group cohesion previously regulated by scent similarity. This is reflected by what political scientists call elective affinities—the notion that there is mutual attraction between ‘the structure and contents of belief systems and the underlying needs and motives of individuals and groups who subscribe to them’ [49].

Many beliefs are not derived from personal experience, but from trusted sources or communities. So, giving up those beliefs may threaten ties with the community. When established beliefs have a useful function there is a tendency to conserve them since the sharing of common beliefs promotes group cohesion. On the other hand, homogenous group thinking prevents creativity which may result from a reluctance to conform with established rules. Rebels threaten the cohesion of the group and in order to keep them under control it is necessary to develop punitive mechanisms that discourage deviating from the status quo [50].

Thus, a strategy based on a hierarchical system of policing develops. But this strategy is not exclusive to humans, or mammalian social groups. It is also observed in groups of social insects such as ants and bees. Note that there is a difference between the evolutionary concepts of “strategies” and “tactics”. While strategies refer to a set of behavioural adaptations that evolved over time, tactics refer to the individual actions taken to pursue a strategy [50, 51]. The concept of utility can also be observed in individuals who believe in conspiracy theories. A conspiracy theory, however unlikely, represents an identification badge identifying that social group. In human societies the sharing of beliefs plays the same function as scent sharing in kin related animal groups. Common beliefs are the “intellectual scent” that unites a group. Conspiracy theories often offer theories that contradict the prevailing or official narrative of facts or events. They offer alternative explanations that appeal to those who believe they have a reason to distrust mainstream narratives. They usually refer to the existence of some hidden enemy and the individual finds safety in the confinements of their like-minded group. The belief in conspiracy theories relies on faith promoted by group think rather than evidence. The individual then finds a false sense of safety inside these ideological bubbles.

Perhaps one of the most puzzling aspects of beliefs which confer survival utility is the placebo effect which seems to have positive effects in healing of the mind and body. Perhaps one of the main characteristics of this effect is that it is grounded on the human’s tendency to magical thinking and embrace convictions rather than simple beliefs.