Pub Date : 2024-01-31eCollection Date: 2024-01-01DOI: 10.1017/ehs.2024.1
Nikhil Chaudhary, Abigail E Page, Gul Deniz Salali, Mark Dyble, Daniel Major-Smith, Andrea B Migliano, Lucio Vinicius, James Thompson, Sylvain Viguier
Among vertebrates, allomothering (non-maternal care) is classified as cooperative breeding (help from sexually mature non-breeders, usually close relatives) or communal breeding (shared care between multiple breeders who are not necessarily related). Humans have been described with both labels, most frequently as cooperative breeders. However, few studies have quantified the relative contributions of allomothers according to whether they are (a) sexually mature and reproductively active and (b) related or unrelated. We constructed close-proximity networks of Agta and BaYaka hunter-gatherers. We used portable remote-sensing devices to quantify the proportion of time children under the age of 4 spent in close proximity to different categories of potential allomother. Both related and unrelated, and reproductively active and inactive, campmates had substantial involvement in children's close-proximity networks. Unrelated campmates, siblings and subadults were the most involved in both populations, whereas the involvement of fathers and grandmothers was the most variable between the two populations. Finally, the involvement of sexually mature, reproductively inactive adults was low. Where possible, we compared our findings with studies of other hunter-gatherer societies, and observed numerous consistent trends. Based on our results we discuss why hunter-gatherer allomothering cannot be fully characterised as cooperative or communal breeding.
{"title":"Hunter-Gatherer children's close-proximity networks: Similarities and differences with cooperative and communal breeding systems.","authors":"Nikhil Chaudhary, Abigail E Page, Gul Deniz Salali, Mark Dyble, Daniel Major-Smith, Andrea B Migliano, Lucio Vinicius, James Thompson, Sylvain Viguier","doi":"10.1017/ehs.2024.1","DOIUrl":"10.1017/ehs.2024.1","url":null,"abstract":"<p><p>Among vertebrates, allomothering (non-maternal care) is classified as cooperative breeding (help from sexually mature non-breeders, usually close relatives) or communal breeding (shared care between multiple breeders who are not necessarily related). Humans have been described with both labels, most frequently as cooperative breeders. However, few studies have quantified the relative contributions of allomothers according to whether they are (a) sexually mature and reproductively active and (b) related or unrelated. We constructed close-proximity networks of Agta and BaYaka hunter-gatherers. We used portable remote-sensing devices to quantify the proportion of time children under the age of 4 spent in close proximity to different categories of potential allomother. Both related and unrelated, and reproductively active and inactive, campmates had substantial involvement in children's close-proximity networks. Unrelated campmates, siblings and subadults were the most involved in both populations, whereas the involvement of fathers and grandmothers was the most variable between the two populations. Finally, the involvement of sexually mature, reproductively inactive adults was low. Where possible, we compared our findings with studies of other hunter-gatherer societies, and observed numerous consistent trends. Based on our results we discuss why hunter-gatherer allomothering cannot be fully characterised as cooperative or communal breeding.</p>","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"6 ","pages":"e11"},"PeriodicalIF":2.6,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10955362/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140185898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30eCollection Date: 2024-01-01DOI: 10.1017/ehs.2024.3
Renée V Hagen, Brooke A Scelza
Sexual conflict theory has been successfully applied to predict how in non-human animal populations, sex ratios can lead to conflicting reproductive interests of females and males and affect their bargaining positions in resolving such conflicts of interests. Recently this theory has been extended to understand the resolution of sexual conflict in humans, but with mixed success. We argue that an underappreciation of the complex relationship between gender norms and sex ratios has hampered a successful understanding of sexual conflict in humans. In this paper, we review and expand upon existing theory to increase its applicability to humans, where gender norms regulate sex ratio effects on sexual conflict. Gender norms constrain who is on the marriage market and how they are valued, and may affect reproductive decision-making power. Gender norms can also directly affect sex ratios, and we hypothesize that they structure how individuals respond to market value gained or lost through biased sex ratios. Importantly, gender norms are in part a product of women's and men's sometimes conflicting reproductive interests, but these norms are also subject to other evolutionary processes. An integration of sexual conflict theory and cultural evolutionary theory is required to allow for a full understanding of sexual conflict in humans.
{"title":"Sex ratios and gender norms: why both are needed to understand sexual conflict in humans.","authors":"Renée V Hagen, Brooke A Scelza","doi":"10.1017/ehs.2024.3","DOIUrl":"10.1017/ehs.2024.3","url":null,"abstract":"<p><p>Sexual conflict theory has been successfully applied to predict how in non-human animal populations, sex ratios can lead to conflicting reproductive interests of females and males and affect their bargaining positions in resolving such conflicts of interests. Recently this theory has been extended to understand the resolution of sexual conflict in humans, but with mixed success. We argue that an underappreciation of the complex relationship between gender norms and sex ratios has hampered a successful understanding of sexual conflict in humans. In this paper, we review and expand upon existing theory to increase its applicability to humans, where gender norms regulate sex ratio effects on sexual conflict. Gender norms constrain who is on the marriage market and how they are valued, and may affect reproductive decision-making power. Gender norms can also directly affect sex ratios, and we hypothesize that they structure how individuals respond to market value gained or lost through biased sex ratios. Importantly, gender norms are in part a product of women's and men's sometimes conflicting reproductive interests, but these norms are also subject to other evolutionary processes. An integration of sexual conflict theory and cultural evolutionary theory is required to allow for a full understanding of sexual conflict in humans.</p>","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"6 ","pages":"e10"},"PeriodicalIF":2.6,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10897493/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139984106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frederik Hartmann, Seán G. Roberts, Paul Valdes, Rebecca Grollemund
Previous work has proposed various mechanisms by which the environment may affect the emergence of linguistic features. For example, dry air may cause careful control of pitch to be more effortful, and so affect the emergence of linguistic distinctions that rely on pitch such as lexical tone or vowel inventories. Criticisms of these proposals point out that there are both historical and geographic confounds that need to be controlled for. We take a causal inference approach to this problem to design the most detailed test of the theory to date. We analyse languages from the Bantu language family, using prior geographic-phylogenetic tree of relationships to establish where and when languages were spoken. This is combined with estimates of humidity for those times and places, taken from historical climate models. We then estimate the strength of causal relationships in a causal path model, controlling for various influences of inheritance and borrowing. We find no evidence to support the previous claims that humidity affects the emergence of lexical tone. This study shows how using causal inference approaches lets us test complex causal claims about the cultural evolution of language.
{"title":"Investigating environmental effects on phonology using diachronic models","authors":"Frederik Hartmann, Seán G. Roberts, Paul Valdes, Rebecca Grollemund","doi":"10.1017/ehs.2023.33","DOIUrl":"https://doi.org/10.1017/ehs.2023.33","url":null,"abstract":"\u0000 Previous work has proposed various mechanisms by which the environment may affect the emergence of linguistic features. For example, dry air may cause careful control of pitch to be more effortful, and so affect the emergence of linguistic distinctions that rely on pitch such as lexical tone or vowel inventories. Criticisms of these proposals point out that there are both historical and geographic confounds that need to be controlled for. We take a causal inference approach to this problem to design the most detailed test of the theory to date. We analyse languages from the Bantu language family, using prior geographic-phylogenetic tree of relationships to establish where and when languages were spoken. This is combined with estimates of humidity for those times and places, taken from historical climate models. We then estimate the strength of causal relationships in a causal path model, controlling for various influences of inheritance and borrowing. We find no evidence to support the previous claims that humidity affects the emergence of lexical tone. This study shows how using causal inference approaches lets us test complex causal claims about the cultural evolution of language.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"11 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editorial. The world has gone mad.","authors":"R. Mace","doi":"10.1017/ehs.2023.32","DOIUrl":"https://doi.org/10.1017/ehs.2023.32","url":null,"abstract":"","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"24 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139010601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As homicide rates spike across the United States, researchers nominate diverse causes such as temperature, city greenness, structural racism, inequality, poverty, and more. While variation in homicide rates clearly result from multiple causes, many correlation studies lack systematic theory needed to identify the underlying factors that structure individual motivations. Building on pioneering work in evolutionary human sciences, we propose that when resources are unequally distributed, individuals may have incentives to undertake high-risk activities, including lethal violence, in order to secure material and social capital. Here we evaluate this theory by analyzing federal data on homicide rates, poverty, and income inequality across all 50 U.S. states for the years 1990, 2000, and 2005 to 2020. Supporting predictions derived from evolutionary social sciences, we find that the interaction of poverty (scarcity) and inequality (unequal distribution) best explains variation in U.S. homicide rates. Results suggest that the increase in homicide rates during the height of the COVID-19 pandemic are driven in part by these same underlying causes that structure homicide rates across the U.S. over the last 30 years. We suggest these results provide compelling evidence to expand strategies for reducing homicide rates by dismantling structures that generate and concentrate sustained poverty and economic inequality.
{"title":"U.S. homicide rates increase when resources are scarce and unequally distributed","authors":"Weston C. McCool, B. Codding","doi":"10.1017/ehs.2023.31","DOIUrl":"https://doi.org/10.1017/ehs.2023.31","url":null,"abstract":"\u0000 As homicide rates spike across the United States, researchers nominate diverse causes such as temperature, city greenness, structural racism, inequality, poverty, and more. While variation in homicide rates clearly result from multiple causes, many correlation studies lack systematic theory needed to identify the underlying factors that structure individual motivations. Building on pioneering work in evolutionary human sciences, we propose that when resources are unequally distributed, individuals may have incentives to undertake high-risk activities, including lethal violence, in order to secure material and social capital. Here we evaluate this theory by analyzing federal data on homicide rates, poverty, and income inequality across all 50 U.S. states for the years 1990, 2000, and 2005 to 2020. Supporting predictions derived from evolutionary social sciences, we find that the interaction of poverty (scarcity) and inequality (unequal distribution) best explains variation in U.S. homicide rates. Results suggest that the increase in homicide rates during the height of the COVID-19 pandemic are driven in part by these same underlying causes that structure homicide rates across the U.S. over the last 30 years. We suggest these results provide compelling evidence to expand strategies for reducing homicide rates by dismantling structures that generate and concentrate sustained poverty and economic inequality.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"23 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138980070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mariana L. Carrito, Francisca Bismarck, Pedro Bem-Haja, David I. Perrett, Isabel M. Santos
Abstract The impact of sexual dimorphism on facial attractiveness has been controversial due to contradictory results, particularly in studies on female preferences. Given that sexually dimorphic facial features, especially more masculine ones, have been previously related to the perception of anger, we investigated the bi-directional influence of emotional expressions and facial masculinity and explored their impact on women's preferences for facial masculinity. We confirmed the effect of facial sexual dimorphism on the perception of emotional cues (happiness and anger) and explored whether smiling or angry expressions influence women's perception of masculinity in male faces. Additionally, we examined women's preferences for emotionally expressive male faces altered along a continuum of masculinity. Results showed that masculinized faces are perceived as angrier, while feminized faces are perceived as happier (Experiment 1), and that angry faces are perceived as more masculine when compared to happy faces (Experiment 2). Noteworthy, our Experiment 3 uncovered a pivotal finding: women prefer reduced feminization in happy faces compared to neutral/angry faces. This suggests that the avoidance response observed towards masculinity is attenuated by a smiling expression. The current study introduces a new perspective to be considered when exploring the role of facial masculinity in women's attractiveness preferences.
{"title":"When he smiles: Attractiveness Preferences for male faces expressing emotions","authors":"Mariana L. Carrito, Francisca Bismarck, Pedro Bem-Haja, David I. Perrett, Isabel M. Santos","doi":"10.1017/ehs.2023.28","DOIUrl":"https://doi.org/10.1017/ehs.2023.28","url":null,"abstract":"Abstract The impact of sexual dimorphism on facial attractiveness has been controversial due to contradictory results, particularly in studies on female preferences. Given that sexually dimorphic facial features, especially more masculine ones, have been previously related to the perception of anger, we investigated the bi-directional influence of emotional expressions and facial masculinity and explored their impact on women's preferences for facial masculinity. We confirmed the effect of facial sexual dimorphism on the perception of emotional cues (happiness and anger) and explored whether smiling or angry expressions influence women's perception of masculinity in male faces. Additionally, we examined women's preferences for emotionally expressive male faces altered along a continuum of masculinity. Results showed that masculinized faces are perceived as angrier, while feminized faces are perceived as happier (Experiment 1), and that angry faces are perceived as more masculine when compared to happy faces (Experiment 2). Noteworthy, our Experiment 3 uncovered a pivotal finding: women prefer reduced feminization in happy faces compared to neutral/angry faces. This suggests that the avoidance response observed towards masculinity is attenuated by a smiling expression. The current study introduces a new perspective to be considered when exploring the role of facial masculinity in women's attractiveness preferences.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"1 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134953560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Ethnic discrimination during pregnancy is linked to maternal psychological distress, adverse birth outcomes, and increased offspring morbidity and mortality. An evolutionary perspective reframes offspring health issues as a risk to maternal fitness. We argue that kin may be evolutionarily motivated to buffer psychosocial stressors for the mother during pregnancy. Previously, we found that the relationship of a pregnant woman with her own mother (fetus’ maternal grandmother, MGM) had a positive association on maternal prenatal psychology, above and beyond her relationship with her fetus’ father. Here, we ask if grandmothers buffer mothers’ prenatal psychological distress from ethnic discrimination. Using self-report data collected from 216 pregnant Latina women living in Southern California, we found discrimination to be significantly, positively associated with depression, anxiety, and stress in linear regression models. MGM communication attenuated the association of discrimination and all three psychological distress measures, adjusting for the mother's relationship with the father. MGM emotional support similarly significantly moderated the relationship of discrimination with depression and anxiety. We did not observe any significant interactions for paternal grandmother relationships. Geographic proximity was not a significant stress-buffer. Results suggest the important role MGMs play in perinatal mental health, and that these benefits exist uncoupled from geographic proximity.
{"title":"Maternal grandmothers buffer the effects of ethnic discrimination among pregnant Latina mothers","authors":"Delaney A. Knorr, Molly M. Fox","doi":"10.1017/ehs.2023.27","DOIUrl":"https://doi.org/10.1017/ehs.2023.27","url":null,"abstract":"Abstract Ethnic discrimination during pregnancy is linked to maternal psychological distress, adverse birth outcomes, and increased offspring morbidity and mortality. An evolutionary perspective reframes offspring health issues as a risk to maternal fitness. We argue that kin may be evolutionarily motivated to buffer psychosocial stressors for the mother during pregnancy. Previously, we found that the relationship of a pregnant woman with her own mother (fetus’ maternal grandmother, MGM) had a positive association on maternal prenatal psychology, above and beyond her relationship with her fetus’ father. Here, we ask if grandmothers buffer mothers’ prenatal psychological distress from ethnic discrimination. Using self-report data collected from 216 pregnant Latina women living in Southern California, we found discrimination to be significantly, positively associated with depression, anxiety, and stress in linear regression models. MGM communication attenuated the association of discrimination and all three psychological distress measures, adjusting for the mother's relationship with the father. MGM emotional support similarly significantly moderated the relationship of discrimination with depression and anxiety. We did not observe any significant interactions for paternal grandmother relationships. Geographic proximity was not a significant stress-buffer. Results suggest the important role MGMs play in perinatal mental health, and that these benefits exist uncoupled from geographic proximity.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":" 26","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135243410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Bonell, Christoph Klebl, Khandis Blake, Scott Griffiths
Abstract Cosmetic surgery is extremely popular. Despite this, negative attitudes towards cosmetic surgery recipients prevail. Across two pre-registered studies, we examined whether intrasexual competitiveness explains these negative attitudes. Participants in Study 1 were 343 (Mean age = 24.74) single heterosexual American women and participants in Study 2 were 445 (Mean age = 19.03) female Australian undergraduate students. Participants in both studies were primed for either low or high intrasexual competitiveness. Contrary to our predictions, we found that priming condition did not influence participants’ derogation and social exclusion of cosmetic surgery recipients. We did, however, find evidence for a ‘relative attractiveness’ halo effect: participants engaged in less derogation and social exclusion when they assumed cosmetic surgery recipients were more attractive than themselves. Overall, we concluded that intrasexual competitiveness does not encourage the stigmatisation of cosmetic surgery recipients and examined alternative explanations for this phenomenon.
{"title":"How intrasexual competitiveness shapes attitudes toward cosmetic surgery recipients","authors":"Sarah Bonell, Christoph Klebl, Khandis Blake, Scott Griffiths","doi":"10.1017/ehs.2023.26","DOIUrl":"https://doi.org/10.1017/ehs.2023.26","url":null,"abstract":"Abstract Cosmetic surgery is extremely popular. Despite this, negative attitudes towards cosmetic surgery recipients prevail. Across two pre-registered studies, we examined whether intrasexual competitiveness explains these negative attitudes. Participants in Study 1 were 343 (Mean age = 24.74) single heterosexual American women and participants in Study 2 were 445 (Mean age = 19.03) female Australian undergraduate students. Participants in both studies were primed for either low or high intrasexual competitiveness. Contrary to our predictions, we found that priming condition did not influence participants’ derogation and social exclusion of cosmetic surgery recipients. We did, however, find evidence for a ‘relative attractiveness’ halo effect: participants engaged in less derogation and social exclusion when they assumed cosmetic surgery recipients were more attractive than themselves. Overall, we concluded that intrasexual competitiveness does not encourage the stigmatisation of cosmetic surgery recipients and examined alternative explanations for this phenomenon.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":" 29","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135243407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Konstantinos Ladas, Stylianos Kavadias, Jeremy Hutchison-Krupat
Abstract An essential feature of human progress is the use of different modes of learning so agents acquire the appropriate behaviour to survive in a changing environment. Learning may result from agents who discover new knowledge on their own (individual learning), or imitate the behaviour of others (social learning). Social learning is less costly than discovery, but imitation might yield no benefit. Early theoretical models of a population consisting of purely individual and purely social learners found that both types are present in an evolutionary equilibrium. However, the presence of social learners did not provide any improvement to the average population fitness. Subsequent research showed the presence of social learners could improve the average population fitness, provided the pure characterisation of the agents’ learning is relaxed. We return to the pure conceptualisation of agents to challenge an assumption in the early work: agents were guaranteed enough resources to perform their desired learning. We show that, if the resources an agent receives are uncertain, this turns social learning into a source of fitness improvement at the population level. Perhaps counter-intuitively, uncertain provision of resources prompts an increase in the proportion of the population who pursue the costlier–individual learning–activity in equilibrium.
{"title":"Cultural Evolution with Uncertain Provision of Learning Resources","authors":"Konstantinos Ladas, Stylianos Kavadias, Jeremy Hutchison-Krupat","doi":"10.1017/ehs.2023.24","DOIUrl":"https://doi.org/10.1017/ehs.2023.24","url":null,"abstract":"Abstract An essential feature of human progress is the use of different modes of learning so agents acquire the appropriate behaviour to survive in a changing environment. Learning may result from agents who discover new knowledge on their own (individual learning), or imitate the behaviour of others (social learning). Social learning is less costly than discovery, but imitation might yield no benefit. Early theoretical models of a population consisting of purely individual and purely social learners found that both types are present in an evolutionary equilibrium. However, the presence of social learners did not provide any improvement to the average population fitness. Subsequent research showed the presence of social learners could improve the average population fitness, provided the pure characterisation of the agents’ learning is relaxed. We return to the pure conceptualisation of agents to challenge an assumption in the early work: agents were guaranteed enough resources to perform their desired learning. We show that, if the resources an agent receives are uncertain, this turns social learning into a source of fitness improvement at the population level. Perhaps counter-intuitively, uncertain provision of resources prompts an increase in the proportion of the population who pursue the costlier–individual learning–activity in equilibrium.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135993168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bonaventura Majolo, Laëtitia Maréchal, Ferenc Igali, Julie Van de Vyver
Abstract For cooperation to be beneficial, cooperators should be able to differentiate individuals who are willing to cooperate from free-riders. In the absence of kin or of familiar individuals, phenotypic similarity (e.g. in terms of language) can be used as a cue of how likely two or more individuals would behave similarly (cooperate or free-ride). Thus, phenotypic similarity could affect cooperation. However, it is unclear whether humans respond to any type of phenotypic similarity or whether only salient phenotypic traits guide cooperation. We tested whether within-group, non-salient phenotypic similarity affects cooperation in 280, 3-10 year old children and in 76 young adults (mean: 19.8 years old) in the UK. We experimentally manipulated the degree of phenotypic similarity in three computer-based experiments. We found no evidence of a preference for, or greater cooperation with, phenotypically similar individuals in children, even though children displayed ingroup preference. Conversely, young adults cooperated more with phenotypically similar than with phenotypically diverse individuals as themselves. Our results suggest that response to non-salient phenotypic similarity varies with age and that young adults may pay more attention to non-salient cues of diversity then children.
{"title":"Cooperation and group similarity in children and young adults in the UK","authors":"Bonaventura Majolo, Laëtitia Maréchal, Ferenc Igali, Julie Van de Vyver","doi":"10.1017/ehs.2023.25","DOIUrl":"https://doi.org/10.1017/ehs.2023.25","url":null,"abstract":"Abstract For cooperation to be beneficial, cooperators should be able to differentiate individuals who are willing to cooperate from free-riders. In the absence of kin or of familiar individuals, phenotypic similarity (e.g. in terms of language) can be used as a cue of how likely two or more individuals would behave similarly (cooperate or free-ride). Thus, phenotypic similarity could affect cooperation. However, it is unclear whether humans respond to any type of phenotypic similarity or whether only salient phenotypic traits guide cooperation. We tested whether within-group, non-salient phenotypic similarity affects cooperation in 280, 3-10 year old children and in 76 young adults (mean: 19.8 years old) in the UK. We experimentally manipulated the degree of phenotypic similarity in three computer-based experiments. We found no evidence of a preference for, or greater cooperation with, phenotypically similar individuals in children, even though children displayed ingroup preference. Conversely, young adults cooperated more with phenotypically similar than with phenotypically diverse individuals as themselves. Our results suggest that response to non-salient phenotypic similarity varies with age and that young adults may pay more attention to non-salient cues of diversity then children.","PeriodicalId":36414,"journal":{"name":"Evolutionary Human Sciences","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135199386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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