The belief in free will can be manipulated, showing an increase of deterministic beliefs, but there are no downstream consequences for world views, attitudes or behavior

Manipulating Belief in Free Will and Its Downstream Consequences: A Meta-Analysis. Oliver Genschow et al. Personality and Social Psychology Review, June 8, 2022. https://doi.org/10.1177/10888683221087527

Abstract: Ever since some scientists and popular media put forward the idea that free will is an illusion, the question has risen what would happen if people stopped believing in free will. Psychological research has investigated this question by testing the consequences of experimentally weakening people’s free will beliefs. The results of these investigations have been mixed, with successful experiments and unsuccessful replications. This raises two fundamental questions: Can free will beliefs be manipulated, and do such manipulations have downstream consequences? In a meta-analysis including 145 experiments (95 unpublished), we show that exposing individuals to anti–free will manipulations decreases belief in free will and increases belief in determinism. However, we could not find evidence for downstream consequences. Our findings have important theoretical implications for research on free will beliefs and contribute to the discussion of whether reducing people’s belief in free will has societal consequences.

Keywords: free will, determinism, belief, meta-analysis, morality, cheating, social behavior, punishment

Progressives selected a more unflattering portrait of a typical conservative face than traditional liberals

The Progressive Values Scale: Assessing the Ideological Schism on the Left. Travis Proulx et al. Personality and Social Psychology Bulletin, June 8, 2022. https://doi.org/10.1177/01461672221097529

Abstract: Progressivism has increasingly challenged traditional liberalism as the dominant influence within left-wing ideology. Across four studies, we developed a measure—the Progressive Values Scale (PVS)—that characterizes distinctly progressive values within the left-wing. In Study 1, left-wing participants evaluated divisive issues, with four scale factors emerging. In Study 2, we confirmed this factor structure and included a battery of personality and values measures to explore individual differences among those who maintain a progressive worldview. In Study 3, we achieved final confirmation of the factor structure and validated the ability of the PVS to assess a distinctly progressive perspective, insofar as progressives generated prototypical faces for Liberals and Conservatives that were markedly distinct from those generated by traditional liberals. In Study 4, we distinguished the PVS from measures of left-wing authoritarianism and demonstrated that it is a better predictor of progressive political preferences and social judgments.

Keywords: political psychology, progressivism, liberalism, assessment, values, personality

The effects of computer-mediated communication on well-being get smaller the closer one looks at them

Computer-Mediated Communication and Well-Being in the Age of Social Media: A Systematic Review. Andrew C High et al. Journal of Social and Personal Relationships, June 8, 2022. https://doi.org/10.1177/02654075221106449

Abstract: The association between computer-mediated communication (CMC) and well-being is a complex, consequential, and hotly debated topic that has received significant attention from pundits, researchers, and the media. Conflicting research findings and fear over negative outcomes have spurred both moral panic and further research into these associations. To create a more comprehensive picture of trends, explanations, and future directions in this domain of research, we conducted a systematic meso-level review of 366 studies across 349 articles published since 2007 that report associations between CMC and well-being. Although most of this research is not explicitly theoretical, several potential theoretical mechanisms for positive and negative effects of CMC on well-being are utilized. The heterogeneity of effects in the studies we reviewed could be explained by the discipline in which the research is conducted, the methodology used, the types of CMC and well-being examined, and the population studied. Our evaluation of this body of research highlights the importance of attending to how we conceptualize communication and well-being, the questions we ask, and the populations and contexts we study when both reading and producing research on CMC and well-being.

Keywords: Computer-mediated communication, well-being, social media, mental well-being, subjective well-being, physical well-being

Conclusions and implications

It is important that scholars follow the evidence rather than the moral panic of the moment. The goal of this review was to provide a broad picture of how the link between CMC and well-being has been studied and how researchers can use this information to most productively build on the current body of literature. Studies of CMC and well-being have been conducted across a range of disciplines, though primarily in psychology, communication studies, medicine, and business. Of note is our observation that disciplinary differences were reflected in divergent findings. The tendency for positive and negative effects to vary by discipline is probably related to the different types of questions researchers ask. For example, studies in communication often focused on positive behaviors such as social support, whereas studies in psychology often examined behaviors associated with poorer well-being, such as addiction and social comparison. We also found that populations that experience stigma or social isolation often benefit from the connection that CMC can provide. In contrast, studies on adolescents, tend to find negative effects, potentially due to their vulnerability to cyberbullying or social comparison. The bulk of what we know, however, relies on Western and Asian samples with good access to CMC, and the few studies that examine other populations suggest that effects might differ for them.

Throughout our meso-level review, we highlighted findings observed within underrepresented populations. In many ways, these findings can be divided into groups with easy access to technology (e.g., adolescents) compared to groups who have recently gained access (e.g., older individuals, people who live in isolated areas). Although some of these novel samples produce distinct findings, many of them fit within larger themes. People who have ready access to technology often exhibit varied but small effects. Immersed in social technologies, they may identify negative repercussions of using technology as particularly salient while positive or neutral effects fade into the background of their daily life. In contrast, people who are isolated, whether because of marginalization or physical locale, often perceive CMC to be beneficial, at least early in its reception.

Rather than focusing on single aspects of identity, future research can take intersectionality more seriously. Although there are many studies on adolescents and some studies on underrepresented cultures and ethnic groups, there are few studies on adolescents from minority groups that focus on the lived experiences of these groups (for exceptions, see Baxter, 2017; Stanton et al., 2017). Further considering multiple aspects of identity, particularly underrepresented or marginalized identities, allows scholars to extend research on topics like cyberbullying or exclusion to consider whether negative outcomes are particularly bad for certain groups (e.g., Black adolescents). Alternatively, perhaps the benefits of social capital or social support are especially valued by the same groups. Taken together, these trends point to the need to contextualize both positive and negative findings relative to each other, the populations within which they occur, the intersectionality inherent in people’s identities, and the wide range of other behaviors that contribute to or detract from well-being. Meier and Reinecke (2021) proposed a six-level hierarchical taxonomy to understand different levels through which CMC can be analyzed. The current meso-level review largely focused on what they labeled the application, branded application, and function levels, while also incorporating additional aspects of research that are not included in their taxonomy. Future research can enhance understanding of the connections between CMC and well-being by examining the intersections among different levels of Meier and Reinecke’s (2021) taxonomy alongside other influential aspects of this domain of research.

As we have outlined above, the link between CMC and well-being appears to be generally small and heterogeneous. This conclusion does not minimize the importance of studying that link. Some populations, such as those who are socially isolated, appear to benefit greatly from the ability to connect with others online. Conversely, some CMC behaviors (e.g., upward social comparison and cyberbullying) are consistently associated with poorer well-being. For people who experience less dramatic effects of CMC, its pervasiveness in everyday life means that even small effects can be consequential. As CMC becomes more embedded in how we relate to and communicate with others, it becomes increasingly important to understand when, how, and for whom CMC use is related to enhanced or impaired well-being. Moreover, it is paramount that researchers understand what people are saying and doing in these channels. Our examination of the literature suggests that we can more precisely account for the associations between CMC and well-being by more carefully considering the questions we ask, the populations in which we ask them, the communication that happens in CMC, its relational and cultural contexts, and the ways we conceptualize well-being.

Individuals steadily have grown less conscientiousness and more neurotic since the beginning of the pandemic

Berg, Cameron. 2022. “Personality Trends over the COVID-19 Pandemic.” PsyArXiv. June 8. doi:10.31234/osf.io/9mu46

Abstract: The COVID-19 pandemic has exhibited significant psychological and behavioral impacts, but a precise account of the way that the pandemic has altered human personality is still highly uncertain. This investigation leverages a dataset of Five Factor Model (“Big Five”) personality results from 2.8-million US adults recorded throughout the duration of the pandemic in order to better understand the relationship between significant COVID-19 trends and population-level trait measurements. Using ordinary correlational and more sophisticated machine learning (ML) techniques, we find that (1) individuals steadily have grown less conscientious and more neurotic since the beginning of the pandemic, that (2) average population-level measures of trait agreeableness increased most strongly in response to shorter-term, transient worsening of the pandemic (e.g., hospitalization spikes), while average population-level measures of trait neuroticism increased most strongly in response to longer-term, cumulative worsening of the pandemic (e.g., total deaths), that (3) average population-level measures of trait openness significantly decreased in response to the shorter-term, transient worsening of the pandemic, and that (4) on average, ML-generated regression models were able to explain approximately half of the variance in population-level trait trajectories solely given regressors associated with the course of the COVID-19 pandemic (e.g., the number of people admitted into the ICU for COVID-19 on a given day of the pandemic). Taken together, these findings are among the first to suggest that, at the population level, the COVID-19 pandemic exhibited specific, measurable, and durable impacts on human personality.

Stronger sex drive in men compared to women, with a medium-to-large effect size: Men more often think and fantasize about sex, more often experience sexual affect like desire, and more often engage in masturbation than women

Frankenbach, Julius, Marcel Weber, David D. Loschelder, Helena Kilger, and Malte Friese. 2022. “Sex Drive: Theoretical Conceptualization and Meta-analytic Review of Gender Differences.” PsyArXiv. June 8. doi:10.31234/osf.io/9yk8e

Abstract: Few spheres in life are as universally relevant for (almost) all individuals past puberty as sexuality. One important aspect of sexuality concerns individuals’ sex drive—their dispositional sexual motivation. A vigorous scientific (and popular) debate revolves around the question of whether or not there is a gender difference in sex drive. Several theories predict a higher sex drive in men compared to women, with some theories attributing this difference to biased responding rather than true differences. Currently, there is little consensus on how to conceptualize sex drive, nor does a quantitative summary of the literature exist. In this paper, we present a theory-driven conceptualization of sex drive as the density distribution of state sex drive, where state sex drive is defined as momentary sexual motivation that manifests in sexual cognition, affect, and behavior. We conduct a comprehensive meta-analysis of gender differences in sex drive based on 211 studies, 856 effect sizes, and 621,463 persons. The meta-analysis revealed a stronger sex drive in men compared to women, with a medium-to-large effect size (g = 0.69, CI95 [0.58, 0.81]). Men more often think and fantasize about sex, more often experience sexual affect like desire, and more often engage in masturbation than women. Adjustment for biased responding reduced the gender difference (g = 0.54). Moderation analyses suggest that the effect is robust and largely invariant to contextual factors. There was no evidence of publication bias. The discussion focuses on validity considerations, limitations, and implications for psychological theory and people’s everyday lives.

Jazz musicians were less conscientious and more open to experience than classical musicians

The musician’s personality: Do personality traits vary according to ensemble membership? Zahava L Heydel, Randyl D Smith, Nels Grevstad. Psychology of Music, June 6, 2022. https://doi.org/10.1177/03057356221096779

Abstract: Despite many decades’ worth of investigations into associations between music and personality, the empirical findings are quite scant and scattered. Perhaps, this is because musicians are a diverse group of people, with far-reaching musical interests and wide-ranging personalities. Little research, however, has investigated whether musicians’ choice of musical genre bears a relationship to their personalities. In this study, we explore the limited literature on the relationship between music ensemble membership and personality by investigating personality differences between jazz and classical ensemble musicians on the Big Five personality dimensions. Musicians (N = 221) were recruited from college music ensembles, an introductory psychology course, a Facebook page, and Amazon Mechanical Turk. Participants completed the Big Five Inventory (BFI), a validated self-report personality questionnaire, and analyses were conducted to compare the scores of jazz musicians to the scores of classical musicians. Significant differences emerged between jazz and classical musicians’ personalities, with gender playing a mediating role. These results may be beneficial for music educators and directors, as knowledge that specific personality traits predict music ensemble membership may help guide instruction techniques, communication, understanding between musicians of different musical genres, and general cooperation between music educators/directors and their ensembles.

Keywords: musicians, personality, classical musician, jazz musician, Big Five model

The evolutionary novelty of childcare by and with strangers: Net of education, earnings, sex, current marital status, and number of children, more intelligent British parents were more likely to resort to paid childcare at ages 33 & 42

The evolutionary novelty of childcare by and with strangers. Satoshi Kanazawa. Journal of Experimental Child Psychology, Volume 221, September 2022, 105432. https://doi.org/10.1016/j.jecp.2022.105432

Abstract: Alloparenting by and with genetically unrelated individuals is evolutionarily novel; thus, the Savanna–IQ Interaction Hypothesis predicts that more intelligent parents are more likely to resort to paid childcare by strangers. Analyses of individual data (National Child Development Study) in the United Kingdom (Study 1) and macrolevel data from the United States (Study 2) and economically developed Organization for Economic Cooperation and Development (OECD) nations (Study 3) confirmed the hypothesis. Net of education, earnings, sex, current marital status, and number of children, more intelligent British parents were more likely to resort to paid childcare at ages 33 and 42; net of female labor force participation rate, median household income, median cost of childcare, and mean education, U.S. states with higher average intelligence had higher proportions of children (ages 0–4) in paid childcare; and net of maternal employment, gross domestic product (GDP) per capita, cost of childcare, and female educational attainment, OECD nations with higher average intelligence had higher proportions of infants (ages 0–2) in paid childcare. The results were remarkably consistent; both across the 50 U.S. states and 45 economically developed OECD nations, a one IQ point increase in the average intelligence of the population was associated with a 1.8% increase in the proportion of children in paid childcare. Contrary to earlier findings, there was some suggestive evidence that the experience of paid daycare might harm the cognitive development of children. The studies point to the importance of evolutionary perspective in developmental psychology and child development.

Keywords: Day careChild careIsraeli kibbutzimTaiwanese sim pua marriagesIncest avoidanceWestermarck effect

Unambiguous chickens were not present until ∼1650 to 1250 BCE in central Thailand; production and storage of rice & millet may have acted as a magnet, thus initiating the chicken domestication process

The biocultural origins and dispersal of domestic chickens. Joris Peters et al. Proceedings of the National Academy of Sciences, 119 (24) e2121978119, June 6, 2022. https://doi.org/10.1073/pnas.2121978119

Significance: Chickens are the world’s most numerous domestic animal. In order to understand when, where, and how they first became associated with human societies, we critically assessed the domestic status of chicken remains described in >600 sites in 89 countries, and evaluated zoogeographic, morphological, osteometric, stratigraphic, contextual, iconographic, and textual data. Although previous studies have made claims for an early origin of chickens, our results suggest that unambiguous chickens were not present until ∼1650 to 1250 BCE in central Thailand. A correlation between early chickens and the first appearance of rice and millet cultivation suggests that the production and storage of these cereals may have acted as a magnet, thus initiating the chicken domestication process.

Abstract: Though chickens are the most numerous and ubiquitous domestic bird, their origins, the circumstances of their initial association with people, and the routes along which they dispersed across the world remain controversial. In order to establish a robust spatial and temporal framework for their origins and dispersal, we assessed archaeological occurrences and the domestic status of chickens from ∼600 sites in 89 countries by combining zoogeographic, morphological, osteometric, stratigraphic, contextual, iconographic, and textual data. Our results suggest that the first unambiguous domestic chicken bones are found at Neolithic Ban Non Wat in central Thailand dated to ∼1650 to 1250 BCE, and that chickens were not domesticated in the Indian Subcontinent. Chickens did not arrive in Central China, South Asia, or Mesopotamia until the late second millennium BCE, and in Ethiopia and Mediterranean Europe by ∼800 BCE. To investigate the circumstances of their initial domestication, we correlated the temporal spread of rice and millet cultivation with the first appearance of chickens within the range of red junglefowl species. Our results suggest that agricultural practices focused on the production and storage of cereal staples served to draw arboreal red junglefowl into the human niche. Thus, the arrival of rice agriculture may have first facilitated the initiation of the chicken domestication process, and then, following their integration within human communities, allowed for their dispersal across the globe.

Discussion

Assessing the Spatiotemporal Pattern of Chicken Domestication.

Two initial hypotheses proposed separate temporal and geographic origins of domestic chickens. Zeuner (5) argued that domestic chickens were present in the Indus Valley during the mature Harappan period (∼2600 to 1900 BCE) and subsequently introduced to Mesopotamia. Based upon the presumption that archaeological bird remains dated to the sixth millennium BCE in Neolithic northern China were chickens, West and Zhou (6) claimed that chicken domestication must have taken place in Southeast Asia prior to this before being translocated into China, and then farther west following a northern route. A more recent study concluded that red junglefowl were domesticated in the Yellow River basin shortly after the onset of the Holocene (8) (SI Appendix, Table S1).

With respect to South Asia, the claim that chickens were present within the Indus Valley Civilization was based upon two bone remains from Harappa (25) and four from Mohenjo-daro (24), as well as an incomplete “hen” figurine from Mohenjo-daro (23, 79). Our reanalysis of the two Harappan bones shows that one is morphologically inconsistent with Gallus, and the other’s taxonomic classification is ambiguous. The taxonomic classification of three of the four fragmentary bird bones from Mohenjo-daro is also questionable. In addition, all of these bones, including a completely preserved femur, pertain to individuals that significantly exceed the size of prehistoric chickens. Finally, all four specimens have been collected in upper strata. Given the propensity for chicken bones to move between stratigraphic boundaries (13), it’s possible these remains are recent intrusions. These lines of evidence call into question the assumption that poultry farming was present in Bronze Age Mohenjo-daro (SI Appendix, Table S3).

Excavations conducted in other Indus Valley Civilization sites and contemporaneous settlements produced additional chicken bones, especially in Saraushtra (SI Appendix, Fig. S2). These specimens were classified as domestic fowl based on the absence of modern wild jungle fowl populations in the region (22) and the aforementioned incorrect claim for fowl husbandry in the Indus Valley. Although currently located beyond the present-day natural distribution of both red and gray junglefowl (Fig. 1 and SI Appendix, Fig. S1), this region shares similar ecological characteristics and borders the region where gray junglefowl is extant (80). It is therefore likely that the natural range of gray junglefowl extended into the Indus River basin during the Mid-Holocene, and that these remains derive instead from local wild populations. This conclusion is supported by the presence of other fauna present in zooarchaeological assemblages, or in Harappan art (including Indian Hog Deer: Axis porcinus; Swamp Deer: Cervus duvauceli; and the Indian Rhinoceros: Rhinoceros unicornis), indicating relatively larger distributions of several fauna in the past (81). The combined weight of this evidence suggests that, contrary to the long-standing hypothesis, chickens were not domesticated in the Indus Valley.

Regarding northern China, subsequent reevaluations of the galliform remains (1, 9), as well as photographs and drawings, demonstrate that they are pheasant bones (2, 82). In addition, high-resolution climate and precipitation records from temperate Holocene East Asia, and the habitat requirements of the vertebrate taxa associated with the pheasants, suggest that the subtropical forest habitat conducive to thermophilic red junglefowl did not extend into northern China during the Holocene climatic optimum (1). Finally, mitochondrial analyses of modern breeds support a late dispersal scenario of chickens into northern China (83). Our analysis thus supports a much later arrival in this region consistent with the first appearance of chickens in Japan in the early first millennium CE, and in Mongolia during the early second millennium CE.

Our combined reanalyses of zooarchaeological, linguistic, genetic, and iconographic evidence suggests the following scenario. The first chickens were likely derived from a population of the subspecies G. gallus spadiceus, whose current range spans southwestern China, northern Thailand, and Myanmar (16) (Fig.1). The first unambiguous chicken bones in the archaeological record are present within the faunal assemblage at Neolithic Ban Non Wat in central Thailand, and date to ∼1650 to 1250 BCE. Once incorporated into human societies, chickens dispersed into and beyond the range of other Gallus subspecies and species. The evidence presented here demonstrates that chickens did not appear in archaeological contexts within Central China, South Asia, or Mesopotamia until the late second millennium BCE, just before their initial presence in Melanesia. By ∼700 BCE, chickens had arrived in Ethiopia and Mediterranean Europe (Fig. 2). This western dispersal was substantially more rapid than the establishment of chicken populations in temperate regions present in higher latitudes (Fig. 2). Overall, our analyses indicate a temporal origin and spread of chickens that substantially postdates many of those suggested by previous studies (6, 8).

A Hypothesis for the Process of Chicken Domestication.

Within the native range of red junglefowl, many Southeast Asian languages refer to chickens as “bamboo fowl,” given how readily they take advantage of cyclical bamboo mass flowering and seeding events (10). Red junglefowl are also known to consume rice grains (Oryza sp.) (44, 84), a staple dietary component of Southeast Asian domestic chickens (85). Rice and millet (Setaria italica) were cultivated by mixed foraging and cereal producing Neolithic communities in mainland Southeast Asia (86–88). An analysis of the material culture (including pottery decoration) associated with these agriculturalists suggests that rice and millet cultivating communities dispersed from the Yangtze valley (89–92) into southern China, where they arrived by the mid-third millennium BCE (90, 93). From there, they continued into peninsular Southeast Asia, where people following distinct dispersal pathways emphasized either rice or millet (94).

Land reclamation for cereal cultivation led to the replacement of primary forest by secondary vegetation, a habitat more suitable for red junglefowl. Outside of bamboo thickets, red junglefowl are known to thrive in slash-and-burn agricultural systems (10). The novel presence of cultivated fields, fallow fields (necessary for either millet or rainfed rice), cereal harvest residues, remainders of human food preparation and consumption, invertebrates associated with keeping pigs and cattle, and other aspects of the human niche may have attracted red junglefowl to human settlements and their immediate catchment.

The long-term abundance of cereals within the human niche would have led to dramatic shifts in selective pressure that lasted multiple generations, including a relaxation of selection against larger clutch size, as well as increased selection against territoriality in cocks (10). These conditions likely also facilitated larger bird population densities near farming communities, followed by subsequent “accommodation” of birds within the village. The availability of cultivated cereals may have therefore catalyzed a shift in the relationship between people and red junglefowl consistent with the commensal pathway (95, 96).

The current archaeobotanical evidence indicates that sites with rice cultivation appeared within the distribution of G. gallus spadiceus [the subspecies recently identified as the most likely progenitor of chickens (16)] from about 2000 BCE in two regions: southern Yunnan and northeast Thailand (Fig. 3 and SI Appendix, Table S4). Although cereal farming was also present at this time within the inferred distributions of Gallus gallus jabouillei and G. gallus gallus, there is as yet no evidence for the early presence of domestic chicken populations. Although there is confirmation of early rice farming near coastal areas and in low-lying wetlands (86, 94), the zooarchaeological records in Neolithic Vietnam, for example, show evidence for the hunting of wetland birds, but lack remains of Gallus (97). In more interior zones, early rainfed rice/millet cultivation likely spurred a tighter relationship between people and G. gallus spadiceus, as attested by the earliest confirmed chicken bones at Ban Non Wat and Non Nok Tha (SI Appendix, Table S2) (98). Because the rice was rainfed, it would have required more land area and fallow cycles relative to later, more productive irrigated rice (87), and these conditions would have created large areas of secondary thicket vegetation. In the northern region of the G. gallus spadiceus distribution, similar processes were likely possible, but detailed avifaunal studies at prehistoric archaeological sites in Yunnan have not yet been carried out.

Fig. 3.

A map depicting the distribution of dated archaeological rice finds taken from the revised Rice Archaeological Database compiled by D.Q.F. and colleagues, RAD 2.0 (90), with newly added archaeological records and cleaned reports with associated dates that appear too early based on current understanding of archaeological chronology. This is especially the case in mainland Southeast Asia where most of the arrival of cereal agriculture is now thought to be ∼2500 BC for northern Vietnam and southernmost China only and ∼2000 BC for the rest of the region (94, 123).

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In regions north of Yunnan, wet rice agriculture, characterized by small-scale, intensive wetland fields in the Yangtze (87, 99), is present as early as 4000 to 3000 BCE, and these wet paddyfield systems spread throughout central China during the Neolithic. Chickens, however, were absent in the Neolithic (100) and only appear ∼1000 BCE (Fig. 3). Relative to wet rice, dry rice and millet cultivation that predominate in the tropical south is characterized by more extensive mosaics of field and fallow, a niche more suited to wild and commensal red junglefowl.

A Combined Chicken–Rice Dispersal Across Asia and Africa.

Following the integration of chickens and human agricultural societies, the correlated spatiotemporal patterns of rice and chicken dispersal across Asia is striking. In South Asia for example, sedentism became widespread in the Ganges plains in the second millennium BCE (22, 101), and domesticated rice, wheat, barley, and other grain crops began to dominate the economy (102, 103). At this time, agriculture in the Deccan focused on small millets, beans, and occasionally wheat and barley (22, 101). It is during this period, perhaps from the later second millennium BCE, that the subsistence context would have been ideal for chickens or commensal jungle fowl, and this timing corresponds with the arrival of bird remains unambiguously identified as chickens in the Indian subcontinent.

While there is evidence for proto-indica rice management by hunter–fisher–gatherers in the middle Ganges plains predating ∼2000 BCE (102, 104, 105), proto-indica rice was managed in natural, seasonal wetlands that were unlikely to attract Gallus in large numbers. This is illustrated by a dearth of Gallus remains and a low level of both cereal production and livestock husbandry in the archaeological record (22). The domesticated indica rice introduced ∼1600 to 1500 BCE in the Upper and Middle Ganges (104, 105) was typically rainfed in more extensive systems with periods of fallow (102, 106), and thus more attractive to fowl. Recent genomic evidence derived from modern populations suggested that although modern domestic chickens in South Asia possess signatures associated with the local subspecies G. gallus murghi, these ancestral affinities are the result not of a local, independent domestication process, but the result of admixture with introduced domestic chickens derived from G. gallus spadiceus (16).

In Iron Age Mesopotamia, rice and millet cultivation may also have been linked to the initiation and intensification of poultry farming. For example, the cultivation of Chinese millets (Panicum miliaceum, Setaria italica) began in the later second millennium BCE (107–109) and intensified after ∼1000 BCE (110, 111), precisely when poultry husbandry becomes visible archaeologically (Fig. 2 and SI Appendix, Table S2). Middle Assyrian texts also confirm that irrigated rice became established in Syria by ∼1100 BCE, and references to this practice increased from the eighth century BCE (112). Thus, alongside the diversification of grain crops, chickens may represent an additional element of the broadening of Near Eastern subsistence practices after the late Bronze Age collapse (45).

There is also a correlation in Africa between the appearance of chickens and rice agriculture. The translocation of chickens to coastal Southeast Africa and the Indian Ocean islands in the eighth/ninth centuries CE coincides with the introduction of Asian crops, such as rice, tree cotton, and mung bean (113). In addition, archaeobotanical evidence in the Niger Basin illustrates the prominent role of cereal diversification, including more widespread rice cultivation and increasing urbanism ∼300 to 900 CE (114), a temporal window that coincides with the first appearance of chickens.

Replicated in the Chinese context: Ethical reflection (college professors) generally has no positive effect on moral behavior

The moral behavior of ethics professors: A replication-extension in Chinese mainland. Tiantian Hou, Xiaojun Ding & Feng Yu. Philosophical Psychology, Jun 5 2022. https://doi.org/10.1080/09515089.2022.2084057

Abstract: The relationship between professional ethical reflection and corresponding moral behavior is an important theme of moral psychology in recent years. Following Schönegger and Wagner’s research in German-speaking countries, through a replication-extension of the original US-based research carried out by Schwitzgebel and Rust, we aim at examining their results in the Chinese context. The previous researchers have shown that ethical reflection generally has no positive effect on moral behavior. A cross validation of this result was conducted in Chinese mainland, and three issues concerning Confucian virtues were added. Through reaching out to 4482 professors and collecting 368 responses altogether, we attempted to explore whether professional ethical reflection can influence normative attitude and the moral attitude-behavior consistency. Unfortunately, the results failed to show a statistically significant difference between ethicists and other professors on most of the moral issues, with the exception of paying academic membership fees and vegetarianism, wherein ethicists do express more stringent normative attitudes, and their moral attitude and self-reported behavior are statistically consistent. Notably, Chinese professors mainly expressed morally neutral attitudes toward the issue of eating meat, and they tended to believe that ethical reflection contributes to more and better moral behaviors.

Keywords: Moral psychologyethical reflectionnormative attitudemoral behaviorattitude-behavior consistencyvegetarianism

Habitual well-digging in a rainforest-living group of East African chimpanzees, which may have been imported into the community’s behavioural repertoire by an immigrant female

Well-digging in a community of forest-living wild East African chimpanzees (Pan troglodytes schweinfurthii). Hella Péter, Klaus Zuberbühler & Catherine Hobaiter. Primates, Jun 6 2022. https://rd.springer.com/article/10.1007/s10329-022-00992-4

Abstract: Access to resources shapes species’ physiology and behaviour. Water is not typically considered a limiting resource for rainforest-living chimpanzees; however, several savannah and savannah-woodland communities show behavioural adaptations to limited water. Here, we provide a first report of habitual well-digging in a rainforest-living group of East African chimpanzees (Pan troglodytes schweinfurthii) and suggest that it may have been imported into the community’s behavioural repertoire by an immigrant female. We describe the presence and frequency of well-digging and related behaviour, and suggest that its subsequent spread in the group may have involved some degree of social learning. We highlight that subsurface water is a concealed resource, and that the limited spread of well-digging in the group may highlight the cognitive, rather than physical, challenges it presents in a rainforest environment.

Discussion

Chimpanzees living in water-restricted areas are able to exploit subsurface water by digging wells to access it (Nishida et al. 1999; McGrew et al. 2003; Hunt and McGrew 2002). Waibira chimpanzees were observed digging wells by hand next to a pool with stagnant surface water, their main water source during the dry season. We did not observe any use of tools for well-digging. Over a period of 377 days across seven annual dry seasons we documented habitual well-digging in four female chimpanzees. Importantly, this happened while stagnant surface water was available at the same time, suggesting they preferred the well water. Other individuals subsequently exploited the pre-dug wells for their own water access, either directly or by using sponges, again while (stagnant) surface water was available nearby.

Although digging behaviour (e.g. play digging) had been observed in the Waibira community prior to ONY’s immigration in 2015, we recorded no observations of well-digging in the community prior to 2015, despite camera trap video recording at the site (ongoing since January 2013) and direct observations during focal follows (ongoing since 2012). We also recorded no indirect evidence of well-digging at the water hole prior to 2015. While it is impossible to rule out that we missed this behaviour or failed to recognise the indirect traces of it, we consider it likely that ONY introduced the behaviour into the Waibira group. First, her competence and frequency of well-digging were remarkable from the beginning, suggesting that she knew the behaviour prior to immigration. Second, and equally remarkable, were the behavioural responses of other adult individuals who closely observed her well-digging behaviour and then exploited her wells over several years, suggesting that the behaviour was previously unknown to other Waibira adults.

A similar pattern was recorded in adult chimpanzees in Bossou, who closely observed (‘peering’) previously unknown nut-cracking behaviour in a field experiment (Biro et al. 2003). It has been argued that peering is a good indicator of ongoing social learning in apes (Schuppli et al. 2016), which is in line with our observations. Since its introduction in 2015, well-digging has now been observed repeatedly and in multiple individuals, suggesting it has spread–potentially by social learning–within the Waibira community. No similar behaviour has ever been observed in the well-studied neighbouring Sonso community (Reynolds 2005), despite three decades of careful observations and the fact that both groups occupy the same continuous forest habitat. Sonso chimpanzees, however, benefit from year-round access to a small river (the Sonso river), which flows across core areas of their territory and provides continuous access to fresh water.

Over the seven-season study period, we observed eight individuals to dig wells, but all four of the habitual well-diggers were females (three adults and one juvenile). While some younger males were observed to dig a well on at least one occasion, no adult male has so far been seen to dig one (although they were observed exploiting wells dug by others, suggesting a preference for the well water over the stagnant water that was still freely available). This female-biased pattern of spread is similar to that observed in Japanese macaques (Macaca fuscata) for potato washing (Nakamichi et al. 1998). Our camera trap coverage of the water hole is incomplete and it was not possible to observe all drinking events or social behaviours. Thus, it is likely that some well-digging and other digging-related behaviour were not captured in our video dataset. However, there is characteristic physical evidence of well-digging that is relatively easy to identify, such as the hole having clearly defined sides; the presence of separate marks made by fingers at the hole’s lip (where the fingers are initially dug into the soil) or in the area where the tailings remain; the presence of a small pile of substrate where the direction of digging with the fingers is consistent; in addition, the likelihood that well-digging has occurred is further supported by the presence of drinking tools in or around the hole (Video S4) (McGrew et al. 2007, 2013). During the same period of observation, the water hole and the surrounding area was surveyed regularly (at least once a week) for another study, and no indirect physical evidence of well-digging was observed prior to 2015. The failure to acquire this–very easily performed–behaviour by more individuals is puzzling, particularly since they have been observed to exploit the wells dug by other individuals. One possible explanation is that, while the physical act of well-digging for subsurface water is easy, the cognitive puzzle presented by its status as a concealed resource is more challenging, particularly given the (short) delay between the action of digging and the appearance of clean water, and the likely absence of clear cues to its presence. For example, in a muddy rainforest water hole olfactory cues to subsurface water presence are likely obscured by those from stagnant surface water. Delayed rewards or trace conditioning is shown to negatively impact the speed of learning compared to direct stimulus association (Kamin 1961; Beylin et al. 2001), and due to its significant cognitive demands, has been proposed as a possible test for animal consciousness (Shea and Heyes 2010). Additional reinforcing factors, such as observing a conspecific well-digging, may facilitate recognition of the connection between the action of manual digging and acquiring clean subsurface water.

Given wider trends in the spread and maintenance of group-specific behaviour in chimpanzees, we predict that in the future we will see (1) further spread of well-digging between adult females and immature individuals of both sexes; (2) matrilineal spread, as three of the habitual well-diggers were mature females, two of them with offspring; and (3) the possible spread to adult males with the maturation and rise in rank of immature male well-diggers.

In conclusion, we describe a new case of well-digging in chimpanzees–the first described for a rainforest-living group. We describe the apparent spread of this behaviour, which was potentially introduced by an immigrant female. The repeated innovation of well-digging across four communities of chimpanzees (McGrew et al. 2003, 2007; Hunt and McGrew 2002) could be explained by individual learning in response to a strong ecological necessity; however, the apparent absence of this behaviour in Waibira prior to ONY’s immigration, followed by its subsequent rapid acquisition by a few–but not many–group members, suggests that there was a socially mediated component to its spread in Waibira. Our observations support previous evidence suggesting that social transmission typically occurs to other younger or low or similarly ranked individuals (Horner et al. 2010). The now habitual use of a technique previously associated with communities that live in savannah or savannah-woodland highlights the importance of seasonal variation as well as broad ecological variation in resource availability for forest-dwelling chimpanzees (Wessling et al. 2018). Irrespective of the typical availability of water as a resource, the limited presence of water during at least some periods of the year appears sufficient to shape chimpanzee behaviour in the Waibira community. Taken together, these observations highlight both the striking variation and flexibility of chimpanzee behavioural repertoires.