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Yurdum L, Singh M, Glowacki L, Vardy T, Atkinson QD, Hilton CB, Sauter D, Krasnow MM, Mehr SA. Universal interpretations of vocal music. Proc Natl Acad Sci U S A 2023; 120:e2218593120. [PMID: 37676911 PMCID: PMC10500275 DOI: 10.1073/pnas.2218593120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 06/21/2023] [Indexed: 09/09/2023] Open
Abstract
Despite the variability of music across cultures, some types of human songs share acoustic characteristics. For example, dance songs tend to be loud and rhythmic, and lullabies tend to be quiet and melodious. Human perceptual sensitivity to the behavioral contexts of songs, based on these musical features, suggests that basic properties of music are mutually intelligible, independent of linguistic or cultural content. Whether these effects reflect universal interpretations of vocal music, however, is unclear because prior studies focus almost exclusively on English-speaking participants, a group that is not representative of humans. Here, we report shared intuitions concerning the behavioral contexts of unfamiliar songs produced in unfamiliar languages, in participants living in Internet-connected industrialized societies (n = 5,516 native speakers of 28 languages) or smaller-scale societies with limited access to global media (n = 116 native speakers of three non-English languages). Participants listened to songs randomly selected from a representative sample of human vocal music, originally used in four behavioral contexts, and rated the degree to which they believed the song was used for each context. Listeners in both industrialized and smaller-scale societies inferred the contexts of dance songs, lullabies, and healing songs, but not love songs. Within and across cohorts, inferences were mutually consistent. Further, increased linguistic or geographical proximity between listeners and singers only minimally increased the accuracy of the inferences. These results demonstrate that the behavioral contexts of three common forms of music are mutually intelligible cross-culturally and imply that musical diversity, shaped by cultural evolution, is nonetheless grounded in some universal perceptual phenomena.
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Affiliation(s)
- Lidya Yurdum
- Child Study Center, Yale University, New Haven, CT06520
- Department of Psychology, University of Amsterdam, Amsterdam1018WT, Netherlands
| | - Manvir Singh
- Department of Anthropology, University of California, Davis, DavisCA95616
| | - Luke Glowacki
- Department of Anthropology, Boston University, Boston, MA02215
| | - Thomas Vardy
- School of Psychology, University of Auckland, Auckland1010, New Zealand
| | | | | | - Disa Sauter
- Department of Psychology, University of Amsterdam, Amsterdam1018WT, Netherlands
| | - Max M. Krasnow
- Division of Continuing Education, Harvard University, Cambridge, MA02138
| | - Samuel A. Mehr
- Child Study Center, Yale University, New Haven, CT06520
- School of Psychology, University of Auckland, Auckland1010, New Zealand
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2
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Abstract
Multiple lines of evidence suggest that there are two major dimensions of social perception, often called warmth and competence, and that warmth is prioritized over competence in multiple types of social decision-making. Existing explanations for this prioritization argue that warmth is more consequential for an observer's welfare than is competence. We present a new explanation for the prioritization of warmth based on humans' evolutionary history of cooperative partner choice. We argue that the prioritization of warmth evolved because ancestral humans faced greater variance in the warmth of potential cooperative partners than in their competence but greater variance in competence over time within cooperative relationships. These each made warmth more predictive than competence of the future benefits of a relationship, but because of differences in the distributions of these traits, not because of differences in their intrinsic consequentiality. A broad, synthetic review of the anthropological literature suggests that these conditions were characteristic of the ecologies in which human social cognition evolved, and agent-based models demonstrate the plausibility of these selection pressures. We conclude with future directions for the study of preferences and the further integration of social and evolutionary psychology.
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Affiliation(s)
| | - Max M Krasnow
- Division of Continuing Education, Harvard University
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3
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Abstract
We discuss approaches to the study of the evolution of music (sect. R1); challenges to each of the two theories of the origins of music presented in the companion target articles (sect. R2); future directions for testing them (sect. R3); and priorities for better understanding the nature of music (sect. R4).
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Affiliation(s)
- Samuel A Mehr
- Department of Psychology, Harvard University, Cambridge, MA02138, , https://, https://projects.iq.harvard.edu/epl
- Data Science Initiative, Harvard University, Cambridge, MA02138
- School of Psychology, Victoria University of Wellington, Wellington6012, New Zealand
| | - Max M Krasnow
- Department of Psychology, Harvard University, Cambridge, MA02138, , https://, https://projects.iq.harvard.edu/epl
| | - Gregory A Bryant
- Department of Communication, University of California Los Angeles, Los Angeles, CA90095, , http://gabryant.bol.ucla.edu
- Center for Behavior, Evolution, and Culture, University of California Los Angeles, Los Angeles, CA90095, USA
| | - Edward H Hagen
- Department of Anthropology, Washington State University, Vancouver, WA98686, USA. , https://anthro.vancouver.wsu.edu/people/hagen
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Young NR, La Rosa M, Mehr SA, Krasnow MM. Does greater morning sickness predict carrying a girl? Analysis of nausea and vomiting during pregnancy from retrospective report. Arch Gynecol Obstet 2020; 303:1161-1166. [PMID: 33098451 DOI: 10.1007/s00404-020-05839-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 10/13/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE The prevalence of severe nausea and vomiting during pregnancy (NVP) requiring hospitalization has been associated with female fetal sex. However, the question of whether fetal sex and less severe forms of NVP share that association has not been investigated. The objective of this study was to evaluate the relationship between fetal sex and the frequency of NVP. METHODS We collected self-reported data from mothers via an international web-based survey on the Amazon Mechanical Turk (MTurk) platform about pregnancy and first trimester NVP history. We considered the covariables of maternal age, parity status, proneness to nausea, geographic cohort, and preconceived notions of a relationship between fetal sex and NVP. RESULTS Two-thousand five hundred and forty-three mothers met the inclusion criteria, yielding data from 4320 pregnancies. Women gestating a female fetus reported higher frequencies of NVP (M = 6.35 on a 1-9 scale) than did women gestating males (M = 6.04, p = .007). This effect held true when all other variables were included in the regression. General proneness to nausea, maternal age, and parity were also significant independent predictors of NVP. CONCLUSIONS Women that carried a female fetus, as opposed to a male fetus, reported significantly higher frequency of NVP during the first trimester of pregnancy. Further research should evaluate both the proximate and ultimate causes of this relationship.
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Affiliation(s)
- Nicola R Young
- Department of Psychology, Harvard University, Cambridge, MA, USA.
| | - Mauricio La Rosa
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, USA
| | - Samuel A Mehr
- Department of Psychology, Harvard University, Cambridge, MA, USA
| | - Max M Krasnow
- Department of Psychology, Harvard University, Cambridge, MA, USA
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5
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Abstract
Music comprises a diverse category of cognitive phenomena that likely represent both the effects of psychological adaptations that are specific to music (e.g., rhythmic entrainment) and the effects of adaptations for non-musical functions (e.g., auditory scene analysis). How did music evolve? Here, we show that prevailing views on the evolution of music - that music is a byproduct of other evolved faculties, evolved for social bonding, or evolved to signal mate quality - are incomplete or wrong. We argue instead that music evolved as a credible signal in at least two contexts: coalitional interactions and infant care. Specifically, we propose that (1) the production and reception of coordinated, entrained rhythmic displays is a co-evolved system for credibly signaling coalition strength, size, and coordination ability; and (2) the production and reception of infant-directed song is a co-evolved system for credibly signaling parental attention to secondarily altricial infants. These proposals, supported by interdisciplinary evidence, suggest that basic features of music, such as melody and rhythm, result from adaptations in the proper domain of human music. The adaptations provide a foundation for the cultural evolution of music in its actual domain, yielding the diversity of musical forms and musical behaviors found worldwide.
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Affiliation(s)
- Samuel A Mehr
- Department of Psychology, Harvard University, Cambridge, MA02138, ; https://; https://projects.iq.harvard.edu/epl
- Data Science Initiative, Harvard University, Cambridge, MA02138
- School of Psychology, Victoria University of Wellington, Wellington6012, New Zealand
| | - Max M Krasnow
- Department of Psychology, Harvard University, Cambridge, MA02138, ; https://; https://projects.iq.harvard.edu/epl
| | - Gregory A Bryant
- Department of Communication, University of California Los Angeles, Los Angeles, CA90095, ; https://gabryant.bol.ucla.edu
- Center for Behavior, Evolution, & Culture, University of California Los Angeles, Los Angeles, CA90095
| | - Edward H Hagen
- Department of Anthropology, Washington State University, Vancouver, WA98686, USA. ; https://anthro.vancouver.wsu.edu/people/hagen
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Mehr SA, Singh M, Knox D, Ketter DM, Pickens-Jones D, Atwood S, Lucas C, Jacoby N, Egner AA, Hopkins EJ, Howard RM, Hartshorne JK, Jennings MV, Simson J, Bainbridge CM, Pinker S, O'Donnell TJ, Krasnow MM, Glowacki L. Universality and diversity in human song. Science 2019; 366:eaax0868. [PMID: 31753969 PMCID: PMC7001657 DOI: 10.1126/science.aax0868] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/24/2019] [Indexed: 12/22/2022]
Abstract
What is universal about music, and what varies? We built a corpus of ethnographic text on musical behavior from a representative sample of the world's societies, as well as a discography of audio recordings. The ethnographic corpus reveals that music (including songs with words) appears in every society observed; that music varies along three dimensions (formality, arousal, religiosity), more within societies than across them; and that music is associated with certain behavioral contexts such as infant care, healing, dance, and love. The discography-analyzed through machine summaries, amateur and expert listener ratings, and manual transcriptions-reveals that acoustic features of songs predict their primary behavioral context; that tonality is widespread, perhaps universal; that music varies in rhythmic and melodic complexity; and that elements of melodies and rhythms found worldwide follow power laws.
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Affiliation(s)
- Samuel A Mehr
- Data Science Initiative, Harvard University, Cambridge, MA 02138, USA.
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand
| | - Manvir Singh
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Dean Knox
- Department of Politics, Princeton University, Princeton, NJ 08544, USA
| | - Daniel M Ketter
- Eastman School of Music, University of Rochester, Rochester, NY 14604, USA
- Department of Music, Missouri State University, Springfield, MO 65897, USA
| | | | - S Atwood
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | - Christopher Lucas
- Department of Political Science, Washington University, St. Louis, MO 63130, USA
| | - Nori Jacoby
- Computational Auditory Perception Group, Max Planck Institute for Empirical Aesthetics, 60322 Frankfurt am Main, Germany
| | - Alena A Egner
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | - Erin J Hopkins
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | - Rhea M Howard
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | | | | | - Jan Simson
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
- Department of Psychology, University of Konstanz, 78464 Konstanz, Germany
| | | | - Steven Pinker
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | | | - Max M Krasnow
- Department of Psychology, Harvard University, Cambridge, MA 02138, USA
| | - Luke Glowacki
- Department of Anthropology, Pennsylvania State University, State College, PA 16802, USA.
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7
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Abstract
Parent-offspring conflict-conflict over resource distribution within families due to differences in genetic relatedness-is the biological foundation for many psychological phenomena. In genomic imprinting disorders, parent-specific genetic expression is altered causing imbalances in behaviors influenced by parental investment. We use this natural experiment to test the theory that parent-offspring conflict contributed to the evolution of vocal music by moderating infant demands for parental attention. Individuals with Prader-Willi syndrome, a genomic imprinting disorder resulting from increased relative maternal genetic contribution, show enhanced relaxation responses to song, consistent with reduced demand for parental investment (Mehr et al., 2017, Psychological Science). We report the necessary complementary pattern here: individuals with Angelman syndrome, a genomic imprinting disorder resulting from increased relative paternal genetic contribution, demonstrate a relatively reduced relaxation response to song, suggesting increased demand for parental attention. These results support the extension of genetic conflict theories to psychological resources like parental attention.
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Affiliation(s)
- Jennifer Kotler
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St., Cambridge, MA 02138, USA.,Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA
| | - Samuel A Mehr
- Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA.,Data Science Initiative, Harvard University, 8 Story St., Suite 380, Cambridge, MA 02138, USA
| | - Alena Egner
- Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA.,Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St., Cambridge, MA 02138, USA
| | - Max M Krasnow
- Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA
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8
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Mehr SA, Singh M, York H, Glowacki L, Krasnow MM. Form and Function in Human Song. Curr Biol 2018; 28:356-368.e5. [PMID: 29395919 DOI: 10.1016/j.cub.2017.12.042] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 12/04/2017] [Accepted: 12/19/2017] [Indexed: 11/24/2022]
Abstract
Humans use music for a variety of social functions: we sing to accompany dance, to soothe babies, to heal illness, to communicate love, and so on. Across animal taxa, vocalization forms are shaped by their functions, including in humans. Here, we show that vocal music exhibits recurrent, distinct, and cross-culturally robust form-function relations that are detectable by listeners across the globe. In Experiment 1, internet users (n = 750) in 60 countries listened to brief excerpts of songs, rating each song's function on six dimensions (e.g., "used to soothe a baby"). Excerpts were drawn from a geographically stratified pseudorandom sample of dance songs, lullabies, healing songs, and love songs recorded in 86 mostly small-scale societies, including hunter-gatherers, pastoralists, and subsistence farmers. Experiment 1 and its analysis plan were pre-registered. Despite participants' unfamiliarity with the societies represented, the random sampling of each excerpt, their very short duration (14 s), and the enormous diversity of this music, the ratings demonstrated accurate and cross-culturally reliable inferences about song functions on the basis of song forms alone. In Experiment 2, internet users (n = 1,000) in the United States and India rated three contextual features (e.g., gender of singer) and seven musical features (e.g., melodic complexity) of each excerpt. The songs' contextual features were predictive of Experiment 1 function ratings, but musical features and the songs' actual functions explained unique variance in function ratings. These findings are consistent with the existence of universal links between form and function in vocal music.
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Affiliation(s)
- Samuel A Mehr
- Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA; Data Science Initiative, Harvard University, 1350 Massachusetts Ave., Cambridge, MA 02138, USA; School of Psychology, Victoria University of Wellington, Kelburn Parade, Wellington 6012, New Zealand.
| | - Manvir Singh
- Department of Human Evolutionary Biology, Harvard University, Peabody Museum, 11 Divinity Ave., Cambridge, MA 02138, USA.
| | - Hunter York
- Department of Human Evolutionary Biology, Harvard University, Peabody Museum, 11 Divinity Ave., Cambridge, MA 02138, USA
| | - Luke Glowacki
- Institute for Advanced Study in Toulouse, 21 Allée de Brienne, 31015 Toulouse, France; Department of Anthropology, Pennsylvania State University, 410 Carpenter Building, University Park, PA 16802, USA
| | - Max M Krasnow
- Department of Psychology, Harvard University, 33 Kirkland St., Cambridge, MA 02138, USA
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9
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Abstract
Why do people sing to babies? Human infants are relatively altricial and need their parents' attention to survive. Infant-directed song may constitute a signal of that attention. In Prader-Willi syndrome (PWS), a rare disorder of genomic imprinting, genes from chromosome 15q11-q13 that are typically paternally expressed are unexpressed, which results in exaggeration of traits that reduce offspring's investment demands on the mother. PWS may thus be associated with a distinctive musical phenotype. We report unusual responses to music in people with PWS. Subjects with PWS ( N = 39) moved more during music listening, exhibited greater reductions in heart rate in response to music listening, and displayed a specific deficit in pitch-discrimination ability relative to typically developing adults and children ( N = 589). Paternally expressed genes from 15q11-q13, which are unexpressed in PWS, may thus increase demands for music and enhance perceptual sensitivity to music. These results implicate genomic imprinting in the psychology of music, informing theories of music's evolutionary history.
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Affiliation(s)
- Samuel A Mehr
- 1 Department of Psychology, Harvard University.,2 Data Science Initiative, Harvard University.,3 Graduate School of Education, Harvard University.,4 School of Psychology, Victoria University of Wellington
| | - Jennifer Kotler
- 5 Department of Organismic and Evolutionary Biology, Harvard University
| | | | - David Haig
- 5 Department of Organismic and Evolutionary Biology, Harvard University
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10
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Krasnow MM, Delton AW. Are Humans Too Generous and Too Punitive? Using Psychological Principles to Further Debates about Human Social Evolution. Front Psychol 2016; 7:799. [PMID: 27303354 PMCID: PMC4882332 DOI: 10.3389/fpsyg.2016.00799] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 05/12/2016] [Indexed: 11/13/2022] Open
Abstract
Are humans too generous and too punitive? Many researchers have concluded that classic theories of social evolution (e.g., direct reciprocity, reputation) are not sufficient to explain human cooperation; instead, group selection theories are needed. We think such a move is premature. The leap to these models has been made by moving directly from thinking about selection pressures to predicting patterns of behavior and ignoring the intervening layer of evolved psychology that must mediate this connection. In real world environments, information processing is a non-trivial problem and details of the ecology can dramatically constrain potential solutions, often enabling particular heuristics to be efficient and effective. We argue that making the intervening layer of psychology explicit resolves decades-old mysteries in the evolution of cooperation and punishment.
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Affiliation(s)
- Max M Krasnow
- Evolutionary Psychology Laboratory, Department of Psychology, Harvard University, Cambridge MA, USA
| | - Andrew W Delton
- Department of Political Science and College of Business, State University of New York at Stony Brook, Stony Brook NY, USA
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11
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Abstract
Children often extend names to novel artifacts on the basis of overall shape rather than core properties (e.g., function). This bias is claimed to reflect the fact that nonrandom structure is a reliable cue to an object having a specific designed function. In this article, we show that information about an object's design (i.e., about its creator's intentions) is neither necessary nor sufficient for children to override the shape bias. Children extend names on the basis of any information specifying the artifact's function (e.g., information about design, current use, or possible use), especially when this information is made salient when candidate objects for extension are introduced. Possible mechanisms via which children come to rely less on easily observable cues (e.g., shape) and more on core properties (e.g., function) are discussed.
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12
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Krasnow MM, Delton AW, Cosmides L, Tooby J. Looking Under the Hood of Third-Party Punishment Reveals Design for Personal Benefit. Psychol Sci 2016; 27:405-18. [DOI: 10.1177/0956797615624469] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 12/07/2015] [Indexed: 11/17/2022] Open
Abstract
Third-party intervention, such as when a crowd stops a mugger, is common. Yet it seems irrational because it has real costs but may provide no personal benefits. In a laboratory analogue, the third-party-punishment game, third parties (“punishers”) will often spend real money to anonymously punish bad behavior directed at other people. A common explanation is that third-party punishment exists to maintain a cooperative society. We tested a different explanation: Third-party punishment results from a deterrence psychology for defending personal interests. Because humans evolved in small-scale, face-to-face social worlds, the mind infers that mistreatment of a third party predicts later mistreatment of oneself. We showed that when punishers do not have information about how they personally will be treated, they infer that mistreatment of other people predicts mistreatment of themselves, and these inferences predict punishment. But when information about personal mistreatment is available, it drives punishment. This suggests that humans’ punitive psychology evolved to defend personal interests.
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Affiliation(s)
| | - Andrew W. Delton
- Department of Political Science, Stony Brook University
- College of Business, Stony Brook University
- Center for Behavioral Political Economy, Stony Brook University
| | - Leda Cosmides
- Center for Evolutionary Psychology, University of California, Santa Barbara
- Department of Psychology, University of California, Santa Barbara
| | - John Tooby
- Center for Evolutionary Psychology, University of California, Santa Barbara
- Department of Anthropology, University of California, Santa Barbara
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13
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Krasnow MM, Delton AW, Cosmides L, Tooby J. Group Cooperation without Group Selection: Modest Punishment Can Recruit Much Cooperation. PLoS One 2015; 10:e0124561. [PMID: 25893241 PMCID: PMC4404356 DOI: 10.1371/journal.pone.0124561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 03/03/2015] [Indexed: 12/03/2022] Open
Abstract
Humans everywhere cooperate in groups to achieve benefits not attainable by individuals. Individual effort is often not automatically tied to a proportionate share of group benefits. This decoupling allows for free-riding, a strategy that (absent countermeasures) outcompetes cooperation. Empirically and formally, punishment potentially solves the evolutionary puzzle of group cooperation. Nevertheless, standard analyses appear to show that punishment alone is insufficient, because second-order free riders (those who cooperate but do not punish) can be shown to outcompete punishers. Consequently, many have concluded that other processes, such as cultural or genetic group selection, are required. Here, we present a series of agent-based simulations that show that group cooperation sustained by punishment easily evolves by individual selection when you introduce into standard models more biologically plausible assumptions about the social ecology and psychology of ancestral humans. We relax three unrealistic assumptions of past models. First, past models assume all punishers must punish every act of free riding in their group. We instead allow punishment to be probabilistic, meaning punishers can evolve to only punish some free riders some of the time. This drastically lowers the cost of punishment as group size increases. Second, most models unrealistically do not allow punishment to recruit labor; punishment merely reduces the punished agent’s fitness. We instead realistically allow punished free riders to cooperate in the future to avoid punishment. Third, past models usually restrict agents to interact in a single group their entire lives. We instead introduce realistic social ecologies in which agents participate in multiple, partially overlapping groups. Because of this, punitive tendencies are more expressed and therefore more exposed to natural selection. These three moves toward greater model realism reveal that punishment and cooperation easily evolve by direct selection—even in sizeable groups.
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Affiliation(s)
- Max M. Krasnow
- Department of Psychology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail:
| | - Andrew W. Delton
- Department of Political Science, College of Business, Center for Behavioral Political Economy, Stony Brook University, Stony Brook, New York, United States of America
| | - Leda Cosmides
- Center for Evolutionary Psychology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - John Tooby
- Center for Evolutionary Psychology, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Anthropology, University of California Santa Barbara, Santa Barbara, California, United States of America
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14
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Delton AW, Krasnow MM. An independent replication that the evolution of direct reciprocity under uncertainty explains one-shot cooperation: commentary on Zefferman. EVOL HUM BEHAV 2014. [DOI: 10.1016/j.evolhumbehav.2014.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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Abstract
Why did punishment and the use of reputation evolve in humans? According to one family of theories, they evolved to support the maintenance of cooperative group norms; according to another, they evolved to enhance personal gains from cooperation. Current behavioral data are consistent with both hypotheses (and both selection pressures could have shaped human cooperative psychology). However, these hypotheses lead to sharply divergent behavioral predictions in circumstances that have not yet been tested. Here we report results testing these rival predictions. In every test where social exchange theory and group norm maintenance theory made different predictions, subject behavior violated the predictions of group norm maintenance theory and matched those of social exchange theory. Subjects do not direct punishment toward those with reputations for norm violation per se; instead, they use reputation self-beneficially, as a cue to lower the risk that they personally will experience losses from defection. More tellingly, subjects direct their cooperative efforts preferentially towards defectors they have punished and away from those they haven’t punished; they avoid expending punitive effort on reforming defectors who only pose a risk to others. These results are not consistent with the hypothesis that the psychology of punishment evolved to uphold group norms. The circumstances in which punishment is deployed and withheld–its circuit logic–support the hypothesis that it is generated by psychological mechanisms that evolved to benefit the punisher, by allowing him to bargain for better treatment.
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Affiliation(s)
- Max M Krasnow
- Center for Evolutionary Psychology, University of California Santa Barbara, Santa Barbara, California, USA.
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16
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Abstract
Current research increasingly suggests that spatial cognition in humans is accomplished by many specialized mechanisms, each designed to solve a particular adaptive problem. A major adaptive problem for our hominin ancestors, particularly females, was the need to efficiently gather immobile foods which could vary greatly in quality, quantity, spatial location and temporal availability. We propose a cognitive model of a navigational gathering adaptation in humans and test its predictions in samples from the US and Japan. Our results are uniformly supportive: the human mind appears equipped with a navigational gathering adaptation that encodes the location of gatherable foods into spatial memory. This mechanism appears to be chronically active in women and activated under explicit motivation in men.
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Affiliation(s)
- Max M Krasnow
- Department of Psychology, University of California, Santa Barbara, CA 93106-9660, USA
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17
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Affiliation(s)
- Andrew W. Delton
- Center for Evolutionary Psychology, University of California, Santa Barbara, CA 93106–9660, USA
| | - Max M. Krasnow
- Center for Evolutionary Psychology, University of California, Santa Barbara, CA 93106–9660, USA
| | - Leda Cosmides
- Center for Evolutionary Psychology, University of California, Santa Barbara, CA 93106–9660, USA
| | - John Tooby
- Center for Evolutionary Psychology, University of California, Santa Barbara, CA 93106–9660, USA
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18
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Abstract
We present evidence for an evolved sexually dimorphic adaptation that activates spatial memory and navigation skills in response to fruits, vegetables and other traditionally gatherable sessile food resources. In spite of extensive evidence for a male advantage on a wide variety of navigational tasks, we demonstrate that a simple but ecologically important shift in content can reverse this sex difference. This effect is predicted by and consistent with the theory that a sexual division in ancestral foraging labour selected for gathering-specific spatial mechanisms, some of which are sexually differentiated. The hypothesis that gathering-specific spatial adaptations exist in the human mind is further supported by our finding that spatial memory is preferentially engaged for resources with higher nutritional quality (e.g. caloric density). This result strongly suggests that the underlying mechanisms evolved in part as adaptations for efficient foraging. Together, these results demonstrate that human spatial cognition is content sensitive, domain specific and designed by natural selection to mesh with important regularities of the ancestral world.
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Affiliation(s)
- Joshua New
- Department of Psychology, Yale University, 2 Hillhouse Avenue, New Haven, CT 06520-8205, USA.
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Krasnow MM, Truxaw D, New J, Gaulin SJC. Shopping for explanations. Response. Science 2007; 318:745. [PMID: 17982757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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