Center for Behavior, Evolution, and Culture

Russell Gray - The Pleasures and Perils of Darwinizing Culture (with Phylogenies)
2010-03-01 00:00 (America/Los_Angeles)
Russell Gray: University of Auckland Department of PsychologyCurrent debates about â€œDarwinizing cultureâ€ have typically focused on the validity of memetics. In this talk I will argue that meme-like inheritance is not a necessary requirement for descent with modification and suggest that an alternative, and more productive, way of Darwinizing culture can be found in the application of computational phylogenetic methods. The benefits of this approach will be illustrated by drawing on my recent work examining linguistic and cultural evolution in the Pacific. I will discuss problems that reticulate evolution allegedly cause phylogenetic analyses and suggest ways in which these problems can be overcome. Throughout I will emphasize that most debates about cultural phylogenies can only be settled by empirical research rather than armchair speculation.http://www.bec.ucla.edu/R.Gray1.pdf

Peter Kim - The Manifestation of Mob Mentalities
2010-02-22 00:00
Peter Kim: USC Department of Management and Organization, Marshall School of Business, University of Southern CaliforniaThroughout history, people have faced the question of how best to respond to a wide range of alleged and/or actual transgressions. A fundamental uncertainty, in this regard, is whether our reactions to such transgressions would differ depending on whether we respond to them as individuals or as groups. This question deserves particular scrutiny given that transgressions can often affect multiple people, the fact that our reactions to such transgressions are rarely made in isolation, the frequency with which these assessments may be made at a collective level, and the potential implications of such assessments for social and organizational life. However, the literature offers little guidance on these issues, given that previous research has focused primarily on the reactions of individuals. The present inquiry seeks to address this limitation: a) by investigating how individuals and groups might differ in their reactions to alleged transgressions, b) by determining the conditions under which such differences would arise, c) by identifying some underlying mechanisms for these differences, and d) by exploring the ways in which transitions between individual and group modes of evaluation may affect these assessments.http://www.bec.ucla.edu/PeterKimPaper.doc

Karen Bales - Neurobiology of parenting in monogamous species
2010-02-08 00:00
Karen Bales: UC Davis Department of PsychologyIn socially monogamous mammals like humans, many individuals such as mothers, fathers, and alloparents often display parenting behaviors. While the hormonal and neural basis of maternal care has been well-studied, both fathering and alloparenting remain more mysterious. Studies from prairie voles and titi monkeys, both monogamous mammals, implicate oxytocin, vasopressin, and glucocorticoids in the regulation of these behaviors. While these hormones may facilitate parenting, developmental data also suggest that the exposure to infants itself changes the brain in a long-term fashion in both males and females. I will discuss what is known about the neurobiology of parenting in males, females, and alloparents, and what opportunities and challenges exist in studying these topics in humans

Eric Vilain - Gaynomics: The Biology of Sexual Orientation
2010-02-01 00:00
Eric Vilain: Professor of Human Genetics, Pediatrics and Urology Director, Center for Gender-Based Biology, Chief, Medical Genetics – Department of Pediatrics, David Geffen School of Medicine at UCLAHuman sexual orientation, oneâ€™s preference for male or female sexual partners, is a largely stable behavioral trait with a significant genetic component. It is a highly sexually dimorphic trait, and as such an interesting model for brain sexual differentiation.
There is much uncertainty about the factors that shape sexual orientation. Although many studies have helped to explain the experience of lesbian, gay, and bisexual (LGB) individuals, empirically supported explanations for the development of an LGB identity are lacking.
Often the media hypes the results of biological research on sexual orientation. Yet, the reports on biological findings are filtered through the journalistsâ€™ understanding of the science and at times are misrepresented. Further, parties who are both for and against the rights of sexual minorities reinterpret these media reports. This can make it difficult to sort fact from fiction.
The purpose of this presentation is to provide an overview on what the biological research has shown in regards to sexual orientation, to assess the current state of the research, and to highlight strengths/limitations of this research. To accomplish this, four main areas will be considered.
Hormones: Research has investigated whether prenatal hormones affect sexual orientation. Although hormones have an impact on behavior, only gross hormonal variations seem to affect sexual orientation.
Anatomical associations: Despite media attention, evidence that non-heterosexual individuals have distinctive anatomical features is far from conclusive. In regards to the anatomical association studies, only non-right handedness and specific anatomical features of the hypothalamus have a consistent relationship with a non-heterosexual orientation.
Birth order: A consistent finding is that having an older brother increases the odd of male homosexuality. Differing theoretical viewpoints on this issue will be discussed.
Genetics: Finally, the most promising evidence for biological influences comes from recent advances in the field of genetics. The validity of studies using â€œfamily treesâ€ and the potential role of the expression of genes on sexual orientation will be discussed. Finally, twin studies will be reviewed, as well our own epigenetic data on twin pairs discordant for sexual orientation.

Nameera Akhtar - Children's learning from third-party interactions
2010-01-25 00:00
Nameera Akhtar: UCSC Department of PsychologyParents and researchers in Western middle-class societies emphasize dyadic interactions and teaching children new skills directly. This emphasis obscures the fact that young children can learn much through observation of othersâ€™ interactions. I will describe the results of several recent studies of young childrenâ€™s learning from third-party interactions. Some of the studies examine learning novel words through overhearing others involve the learning of novel actions (imitative learning). The findings indicate that learning from third-party interactions is a robust skill seen in children as young as 18 months, and suggest that this type of learning may rely on emerging social-cognitive skills that enable the child to imagine herself in the third-party interaction.

Tim Waring - Do Ethnic Divisions Restrict Sustainable use of Natural Resources? A case study from Tamil Nadu
2010-01-15 00:00
Tim Waring: UC Davis Department of Environmental Science and PolicyNumerous scholars have shown that increasing ethnic diversity is correlated with reduced cooperation and fewer public goods. This result has significant implications for development policy, lowering expectations for success in public infrastructure investment with ethnically diverse populations. I present evidence that ethnic hierarchy may be driving the observed effect of ethnic diversity. Ethnic hierarchy is naturally confounded with ethnic diversity because hierarchy cannot logically exist without diversity and because diversity without hierarchy may be exceedingly rare. To determine which factor is a greater constraint on cooperation, I tested the strength of both ethnic diversity and ethnic hierarchy as cooperative limitations using public goods experiments with caste groups in South India. I show that the effect of ethnic diversity is neutralized when relatedness between individuals is taken into account. However, ethnic hierarchy remains severely damaging to public goods cooperation, when all variables are accounted for, and is a required variable for any explanatory model. Moreover, the influence of social momentum is significant. I find that the initial behavior in the game determines the long run outcome, while the cooperative momentum is carried forward in the round-by-round decisions.http://www.bec.ucla.edu/TimWaringSlides.pdf

Lynn Fairbanks - Genetic, Maternal and Life History Influences on Sociability in Vervet Monkeys
2010-01-11 00:00
Lynn Fairbanks: UCLA Department of Psychiatry & Biobehavioral SciencesThe ability to form and maintain social relationships is an important attribute that has broad implications for health and fitness in humans and nonhuman primates. In this presentation, I will describe the development of a quantitative measure of sociability in the Vervet Research Colony, a multigenerational pedigreed colony of vervet monkeys, and present evidence for the consistency, specificity and heritability of sociability as a trait. Mean Sociability scores are affected by life history variables, including age, sex, male emigration, and the presence of infants, but longitudinal analysis indicates that individual differences are maintained over time and across life stages. Because of the importance of matrilineal social relationships in primate societies, including the social â€˜inheritanceâ€™ of dominance rank for females, there is a possibility of maternal environmental effects on sociability. To account for this, we include a component for shared maternal environment in a statistical genetics analysis to identify the contributions of genetic and maternal effects on trait variation, using the extended pedigree. The results indicate there are strong genetic contributions to variation in Sociability scores for both males and females, with maternal effects accounting for a smaller but statistically significant portion of the variance for females but not for males. The final part of the presentation will provide evidence for effects of variation in sociability on male reproductive success.

Adriana Galvan - Adolescence as a developmental period of increased risk-taking and reward sensitivity: Insights from Neuroimaging
2010-01-04 00:00
Adriana Galvan: UCLA Department of PsychologyAdolescence is a developmental period marked by heightened sensitivity to reward and increased proclivity towards risk-taking behavior. These behavioral changes are paralleled by significant developmental changes in neural circuitry related to reward processing and cognitive control. In this talk, I will describe recent data on adolescent brain development, propose a neurobiological model to describe adolescent risk-taking behavior, and provide a framework for how these neuroimaging insights might be used for intervention and prevention of harmful risk-taking behaviors during adolescence.

Catherine Reed - The Role of Specialized Body Processing for Embodied Social Perception
2009-11-30 00:00
Catherine Reed: Claremont-McKenna College Department of PsychologySocial psychologists have embraced the tenants of embodied cognition to explain how we understand the emotions of others. They claim that the reinstantiation of previous sensorimotor experience during emotional and social information processing is an essential process for understanding othersâ€™ emotions (e.g., Neidenthal, Barsalou, Winkielman, Krauth-Gruber, & Ric, 2005). In this talk I suggest that current models of embodied emotion are missing the necessary body-processing mechanisms from which the simulations of emotional experience operate. Further, if one cannot create the basic correspondences between another personâ€™s body and oneâ€™s own then one cannot engage in the appropriate simulation process which can lead to social-emotional deficits such as those observed in autism spectrum disorders.

David Liu - Asking
2009-11-23 00:00
David Liu: UCSD Department of PsychologyMuch research and debate around theory of mind (the ability to attribute mental states to actions) have revolved around whether X have a theory of
mind. X might be 3-year-olds, infants, children with autism, chimpanzees, rhesus macaques, and so forth. I will argue that the better question is what aspects or types of theory of mind are used by X. Numerous studies have shown that children develop different components or aspects of mental-state understanding at different ages, and nonhuman animals demonstrate some components of mental-state understanding in certain situations. Research in my lab has shown that children with different developmental disabilities and typically-developing children from different cultures have shared and nonshared trajectories in their developmental progression of understanding different mental states. In addition, we have discovered different neural circuitries associated with reasoning about different mental states. Our findings provide a framework for understanding similarities and differences in mental-state understanding across different human populations and different species.

John Novembre - Spatial population structure and the genetic basis of adaptation in human populations
2009-11-16 00:00
John Novembre: UCLA Department of Ecology and Evolutionary Biology & Interdepartmental Program in BioinformaticsNovel technological developments are providing an unprecedented opportunity to study the geographic distribution of human genomic diversity. This information has been leveraged to study population structure and interrogate signatures of natural selection. In this talk I will review emerging results from geographic studies of human genetic variation that provide insights into 1) human population structure; and 2) the genetic basis of the response by human populations to recent selective pressures. http://www.bec.ucla.edu/NovembreTalk.pdf

Katerina Semendeferi - Neuroanatomical perspectives on the evolution of the mind
2009-11-09 00:00
Katerina Semendeferi: UCSD Department of AnthropologyThe organ of the mind, the brain, is the focus of several fields of study. This lecture will address the role of neuroanatomy in reconstructions of cognitive evolution. It will present new data on the internal organization of the brain of humans and great apes and will revisit, in a critical light, some of the older data sets widely used in primate evolutionary studies. The lecture will address the challenges of reconstructing cognitive evolution based on animals like the apes that cannot be studied invasively, the significance of including closely related taxonomic groups in studies of human evolution and the issues involved in transferring brain/mind data from animal models to hominids that are characterized by differences in brain size and socioecological adaptations.

Steve Neuberg - Toward a Functional, Affordance-Centered Model of Person Perception, Prejudices, and Social Interaction: Taking into Account Life History and Ecological Considerations
2009-11-02 00:00
Steve Neuberg: Arizona State University Department of PsychologyTraditional psychological and social science theories fail to account for the complexity and nuance that characterize people’s prejudices and the manner in which, more generally, people view and interact with one another. I am developing an alternative, functional, affordance-based model, one positing (1) that our views of others are based on our inferences about their goals, the behavioral strategies they employ to reach them, and the tangible threats and opportunities afforded us by those strategies, and (2) that these goal and strategy inferences are themselves heuristically inferred from others’ life history standing (i.e., age X sex categorization) in combination with stereotypes about the behavioral strategies favored by the different physical and social ecologies in which people live (i.e., “ecology stereotypes”). This vertically integrative framework-linking life history and ecological considerations to person perception processes-provides a more compelling account for a wide range of psychological and social phenomena related to intergroup stereotypes and prejudices, within-coalition stereotypes and prejudices, various social-cognitive biases, and the general accuracy of person perception and stereotypes.

Andrew Shaner - Autism as the low-fitness extreme of a parentally selected fitness indicator
2009-10-26 00:00
Andrew Shaner: UCLA Semel Institute for Psychiatry and Biobehavioral Sciences; Deputy Chief of Psychiatry and Mental Health, VA Greater Los Angeles Healthcare SystemIn many species, siblings compete for parental care and feeding, while parents must allocate scarce resources to those offspring most likely to survive and reproduce. This could cause offspring to evolve traits that advertise health, and thereby attract parental resources. For example, experimental evidence suggests that bright orange filaments covering the heads of North American coot chicks may have evolved for this fitness-advertising purpose. Suppose that the ability of infants and very young children to charm their parents evolved as a parentally selected fitness indicator. Young children would vary greatly in their ability to charm parents, that variation would correlate with underlying fitness, and autism could be the low-fitness extreme of this variation.
This general version of our hypothesis can explain why autism begins in childhood, why it is highly heritable, why the responsible genes have been so hard to find, why it is more common in boys and more severe in girls and why it is associated with environmental hazards, developmental abnormalities and increased mortality. Among its predictions is that autism will be more common in populations with historically high rates of genetic polyandry.
In addition to the general hypothesis, suppose that a key component of charm involves infant social behaviors that prolong breast feeding and thereby delay conception of a younger sibling. If true, this would explain why autism impairs social abilities so early and so profoundly. It would also predict that (1) within populations, age at onset of autism will parallel age at onset of weaning, (2) autism will be associated with scarce environmental resources and early weaning, (3) delaying weaning will protect against autism (4) close relatives will show higher variance in infant social ability (including its anatomical and neurophysiological bases), and in subsequent birth interval, and (5) infant social ability will correlate positively with both underlying fitness and parental resource allocation (e.g., intensity and duration of breast-feeding).http://bec.ucla.edu/papers/Shaner08.pdf

Steve Frank - Demography and timescale in social evolution
2009-10-19 00:00
Steve Frank: UC Irvine & Santa Fe Institute Department of Ecology and Evolutionary BiologyCurrent studies of biological sociality tend to ignore two key factors: the consequences of social traits on long-term aspects of survival and fecundity (demography), and the tension between short and long time scales of success. I use several examples from the biology of microbes to illustrate these fundamental processes of sociality, which apply to any problem that can be framed in terms of natural selection or economic efficiency. For those interested in the particular biological examples, here is a brief summary. Microbes secrete molecules to modify their environment. Secretions dislodge and bind iron, manipulate host defenses, build protective biofilm structures, and communicate information to neighboring microbes. Successful modulation of the environment and successful communication require collective action by a large population of microbes. Recent studies show that kin or group selection powerfully shapes the ways in which microbes collectively communicate and modify their environment. Others studies have shown that the basic design of metabolism and cellular biochemistry may also be influenced by social processes. Competition favors fast extraction and use of resources, reducing metabolic efficiency and leading to low yield per unit of resource. I place these microbial processes into the broad framework of economic and life history theories of biology. I also show that demographic and timescale processes lead to new predictions about microbial pathogenesis and metabolism.

Bruce Bridgeman - Treading a Slippery Slope: Slant Perception in Near and Far Space
2009-10-12 00:00
Bruce Bridgeman: UC Santa Cruz Department of PsychologyEstimation of slope is an everyday tool for navigating the external world. Previous studies have found that slopes are overestimated more greatly with a verbal than with a proprioceptive measure. Since some neurons in the premotor cortex respond differently to objects within armâ€™s reach, we hypothesized that slope estimation may also be affected by neural pathways that respond differently to identical visual information at different distances. Alternatively, vision may be warning us about the greater effort required to walk up a slope. Verbal estimates greatly overestimated the actual slope, and increased logarithmically with distance from the participant, contradicting both theories. Proprioceptive estimates were more accurate. When participants experience a slope directly by walking up and down a hill prior to making estimates, their estimates remain unchanged. Increases in perceived slope with distance depend upon range of the segment judged, not length of the segment. The results can be interpreted as an implicit slope, previously measured only in darkness, modulated by depth cues available at near distances. http://www.bec.ucla.edu/slopes09.pdf

Greg Hickok - On the nature of auditory-motor interaction in speech processing: implications for the interpretation of mirror neurons and beyond
2009-10-05 00:00
Greg Hickok: UC Irvine Cognitive Sciences & Center for Cognitive NeuroscienceThere are two ideas regarding how auditory and motor speech systems interact in language processing. A popular view in the neuroscience community is that motor systems play an important role in the perception of speech. This is an old idea that has been largely (if not completely) abandoned on empirical grounds by the speech science community. However, the discovery of mirror neurons in the macaque brain has resurrected the hypothesis among neuroscientists. The other idea regarding auditory-motor interaction comes out of the motor control literature which has provided compelling evidence that the auditory system plays an important role in speech production. I will review the evidence, current and past, for these two hypotheses and conclude (i) the motor system is not necessary for speech perception, (ii) the motor system may be able to exert a top-down influence on auditory speech perception system but the evidence remains inconclusive and even if real the effects are relatively minor, (iii) there is strong evidence for the reverse relation, that auditory systems play a critical role in aspects of speech production. I will also review a number of fMRI and lesion studies aimed at mapping the cortical circuit supporting sensory-motor interaction in speech processing.

Aaron Sell - An evolutionary-computational model of human anger
2009-09-28 00:00
Aaron Sell: UCSB Department of PsychologyAnger can be understood as a cognitive mechanism designed by natural selection to negotiate conflicts of interest in ways similar to, but distinct from, non-human animal conflict. The Recalibrational Theory of anger uses an evolutionary biological framework to predict the major features of anger and explain their computational structure by reference to this function. Datasets collected from five distinct cultures address the major features of anger including under what conditions anger is evoked, when aggression is used by the anger system, which individuals set lower thresholds for anger and aggression, why and how anger triggers modifications of the face and voice, and how one predicts and explains the computational structure of anger-based arguments. The data demonstrate that anger is a well-designed system for recalibrating targets in ways that minimize immediate and future costs resulting from conflicts of interest.http://www.bec.ucla.edu/SellTalk.pdf

Devesh Rustagi - Conditional Cooperation Norm, Altruistic Punishment, and Participatory Forest Management in Ethiopia
2009-06-03 00:00
Devesh Rustagi: Swiss Federal Institute of Technology, Zurich – Department of Environmental Policy and EconomicsRecent research suggests that the power of conditional cooperation norm and punishment of norm violators in sustaining cooperation depends on behavioral type composition of a group, which has been shown, experimentally, to have a predictive effect on cooperation outcome. However, because the existing evidence is exclusively based on experiments with a handful of students from the industrialized west, fundamental questions on the occurrence of this evidence across cultures, in a real world setting, and itâ€™s policy relevance remain unanswered. Here, we report results from experiments and surveys with 679 members belonging to 49 forest user societies engaged in the management of common property forests in Ethiopia. We find that, first, 35 % members behave as conditional cooperators. Second, the share of conditional cooperators in a society has a significantly positive effect on the societyâ€™s forest management outcome, even when we control for structural determinants of cooperation. Third, conditional cooperators use costly monitoring as a mechanism to achieve a better forest outcome. The unique field settings allow us to generate this evidence in conditions where endogenous group formation, high migration and reverse causality have been ruled out. Our findings provide empirical support to the models of punishment and cultural group selection.

Ruth Mace - Cultural Evolution and the Behavioural Ecology of Fertility Decline
2009-06-01 00:00
Ruth Mace: University College London Department of AnthropologyA behavioural ecological approach to human birth rates suggests they should vary according to the costs of raising children to adulthood. Demographers and most other social scientists are sceptical of this view, not least because birth rates are generally lowest in the wealthiest countries; most favour arguments based on cultural changes and cultural influences. I will argue that evolutionary arguments based on costs and benefits and on cultural influence are not mutually exclusive and that variation in birth rates both within populations and also across populations can be understood in terms of different levels of parental investment and different constraints on parents. I will draw on data from Kenya, Ethiopia, the Gambia and the UK to illustrate these points.

Athena Aktipis - Walking Away from the Haystack: Conditional Movement Favors the Evolution of Cooperation in Groups
2009-05-27 00:00
Athena Aktipis: University of Arizona Department of Ecology and Evolutionary BiologyModels such as Maynard Smithâ€™s Haystack model have shown that high rates of movement (i.e., migration, mixing, dispersal) undermine the evolution of cooperation. However, these models generally assume that movement is unconditional. The present model replaces the assumption of unconditional movement with conditional movement; individuals stay in groups that provide higher returns (by virtue of having more cooperators), and â€˜Walk Awayâ€™ from groups providing low returns. Implementing this conditional movement rule generates a number of findings including: 1) when individuals have high thresholds, corresponding to low tolerance for defectors, this lead to selection for cooperation, 2) high thresholds lead to high rates of movement initially and lower rates of movement after selection for cooperators, and 3) population structure becomes more stable after selection increases the proportion of cooperators in the population. These findings challenge the standard view derived from Maynard Smithâ€™s Haystack model and others that high rates of movement undermine selection for cooperation. In contrast, the current model demonstrates that high rates of conditional movement can be associated with stronger selection for cooperation. These results show that high rates of migration observed in nature are not prohibitive for the evolution of cooperation, as standard group selection models have assumed.http://www.bec.ucla.edu/AktipisWalkingAwayTextAndFigs.doc

Nina Jablonski - The Evolution and Significance of Human Nakedness
2009-05-20 00:00
Nina Jablonski: Penn State Department of AnthropologyHumans are distinguished from other primates by being functionally hairless over most of their bodies. This condition evolved because hairlessness facilitated cooling of the body by sweating. The evaporative cooling made possible by sweating results in whole-body cooling of blood flowing in superficial vessels, and the maintenance of constant brain temperature. The combination of anatomical, physiological, and new genetic information pertaining to the structure and function human skin have helped to â€œlay bareâ€ the evolution of human hairlessness and sweatiness. Hairlessness had major consequences for the evolution of skin pigmentation and the communication of visual information and signals through elaborated facial expressions and, later, body painting and decoration.http://www.bec.ucla.edu/JablonskiTalk.pdf

Daniel Geschwind - Transcriptome Organization in Human and Primate Brain: Connecting Genes to Brain to Cognition and Behavior
2009-05-18 00:00
Daniel Geschwind: UCLA Departments of Human Genetics, Neurology, and PsychiatryWe are interested in understanding how genes influence human cognition and behavior, leading to unique human cognitive specializations, such as language. Advances in molecular and statistical genetics now allow us to identify genes that may be responsible for the emergence of some of these human cognitive features. But convergent approaches relying on data from several levels are necessary to understand a particular geneâ€™s relationship to brain structure and function. To do this, we have undertaken a multidisciplinary approach involving the study of human diseases affecting these features, such as autism, as well as human brain evolution. We have begun to develop methods that try to take into account the systems level organization of gene expression (the transcriptome), and applied these to large scale data sets. This has revealed a previously unrecognized organization to the transcriptional program in brain, which provides a framework on which to understand adaptive changes in gene expression on the human lineage.http://www.bec.ucla.edu/OldhamEtAlNatureNeuroscience.pdf

Joseph Manson - Adherence to Conversational Norms in Interactions Among Strangers: Effects on Cooperation and Expectations of Cooperation
2009-05-11 00:00
Joseph Manson: UCLA Department of AnthropologySeveral studies have shown that, following brief interactions among strangers, subjects perform better than chance at predicting whether their co-subjects will defect in a one-shot Prisonerâ€™s Dilemma Game (PDG). However, previous work did not explore how such predictive accuracy was possible. Theoretical work suggests that adherence to â€œarbitraryâ€ norms serves a signaling function that allows individuals to assort so as to maximize coordination and cooperative efficiency. One set of norms, documented by Conversation Analysis (CA), concerns the details of face-to-face interaction, such as respecting interlocutorsâ€™ rights to complete each turn constructional unit (TCU). We hypothesized that Defection in a PDG and predictions of co-subjectsâ€™ Defections would be more likely vis-Ã -vis unfamiliar interlocutors who violated conversational norms at higher frequencies. We videotaped short conversations among same-sex triads of previously unacquainted university students who were naÃ¯ve to the impending PDG. We then separated participants and directed each of them to (a) play a one-shot PDG with each of their two co-participants and to predict one anotherâ€™s play decisions and (b) complete the Levenson Self-Report Psychopathy Scale (LSRP) along with some demographic questions. From each videotaped conversation, a mean of 3.93 min was transcribed using CA methods. Subjects chose to cooperate in 67.7% of decisions, comparable to previous studies of face-to-face interaction. However, participants performed no better than chance at predicting one anotherâ€™s game play decisions. Nonetheless, personality and conversational behavior were related to one another and to objective outcomes like game play and earnings, in both expected and unexpected ways. We discuss these results with reference to the co-evolution of human cultural variation, cultural capacities and social judgment mechanisms.

Scott Johnson - Mental Rotation in Adults and Infants: A Sex Difference
2009-05-04 00:00
Scott Johnson: UCLA Department of PsychologyMental rotation (MR) is the process by which people imagine how an object would look when rotated into a different orientation in space; it may be related to performance on tasks like perspective-taking and navigation. Men typically perform faster and more accurately than women on MR tasks. Known influences on MR performance in adults are both biological (e.g., exposure to testosterone) and experiential (e.g., practice at spatial tasks), raising vital questions about the developmental origins of MR. Until recently, developmental studies were limited to children 4 years and older. This talk will present evidence that sex differences in MR performance are present far earlier, and can be observed in preverbal infants. I will also discuss the influence of task demands on MR in infants, and the possible biological and environmental contributions to performance that may shed light on the intersection of visual/motor skills and mental imagery of 3D objects early in life.http://www.bec.ucla.edu/MooreJohnson2008.pdf

Paul Mellars - Rethinking Modern Human Behavioural Origins and Dispersal: Archaeological and Genetic Perspectives
2009-04-29 00:00
Paul Mellars: University of Cambridge Department of ArchaeologyResearch over the past ten years in both DNA studies and archaeology has provided some remarkable new insights into the origins of biologically and behaviourally modern human populations, and their widespread dispersal from Africa to the rest of the world around 60,000 years ago.
The combination of DNA studies and recent finds of skeletal remains show that essentially ‘modern’ humans had emerged in Africa by at least 150-200,000 years ago, and subsequently spread from Africa into both Asia and Europe around 55-60,000 years ago, where they rapidly replaced the pre-existing “archaic” populations (including the Eurasian Neanderthals) within a matter of a few thousand years.
This talk will focus specifically on the patterns of dispersal of biologically and behaviourally modern humans from Africa, and the nature of the cultural and behavioural adaptations which made this dispersal possible. The aim will be to compare and integrate evidence from both genetic (i.e. DNA) studies and the recent spate of new archaeological discoveries in Africa and elsewhere. The talk will focus on the two questions of (a) why there was a delay of around 100,000 years between the initial emergence of modern Homo sapiens in Africa and their subsequent dispersal to the rest of the world; and (b) what range of behavioural innovations and adaptations allowed the widespread geographical dispersal of modern humans into a range of new and sharply contrasting environments, and the rapid replacement of the pre-existing ‘archaic’ populations in these regions, within such a short space of time. How far these behavioural innovations can be attributed to a major neurological change, and how far to simple cumulative ‘feedback’ processes of technological, social and other behavioural changes remains a central and critical question for future research.http://www.bec.ucla.edu/MellarsDispersalModel.pdf

Jenessa Shapiro - Perceiving White Norms: Ironic Effects in Blacks' versus Whites' Judgments of Minority Targets
2009-04-27 00:00
Jenessa Shapiro: UCLA Department of PsychologyConformity to a perceived norm is a common strategy used to gain the approval of one’s interaction partners. Identifying a group norm is ordinarily relatively simple. However, this task may be especially difficult when the norm is held by a group to which one does not belong, as is the case in intergroup interactions. In contemporary American society, Whites tend to believe that norms condemning public expressions of racial prejudices are pervasive (e.g., Dovidio & Gaertner, 1986). In contrast, Black Americans tend to view normative White behavior as prejudicial against themselves and other minority groups (e.g., Neimann, Jennings, Rozelle, Baxter, & Sullivan, 1994). The present research examined some ironic implications of this divergent perception of White prejudice-relevant norms. In one study, when evaluations of a Native American job candidate were to be made public to an unfamiliar group of White males upon whom participants were dependent, White men expressed less prejudice whereas Black men expressed greater prejudice, relative to when these responses remained private. In contrast, White and Black females expressed no prejudice when their evaluations were to be public to White females, although Black females expressed generally more favorable judgments of both White and Native American candidates. Follow-up studies support the hypothesis that differential inferences about White prejudice norms underlie this pattern of findings: The public judgments made by Black males (compensatory conformity) and Black females (compensatory pleasantness) can be seen as strategies aimed at reducing the likelihood that they themselves will be discriminated against in an intergroup interaction.

Edouard Machery - Did Morality Really Evolve?
2009-04-20 00:00
Edouard Machery: University of Pittsburgh Department of History and Philosophy of ScienceThat morality evolved is a commonplace among evolutionary biologists, psychologists, and anthropologists. In this talk, I will however argue that biologists, psychologists, and anthropologists have failed to pay enough attention to the differences between three distinct interpretations of the hypothesis that morality evolved: (1) some components of moral cognition (e.g., some particular emotions, concepts, or norms) evolved, (2) a capacity to grasp and be motivated by norms in general evolved, and (3) a capacity to grasp and be motivated by a distinctive type of norms evolved. Under the first two interpretations, it is fairly uncontroversial that morality evolved, while under the third and most interesting interpretation, the hypothesis that morality evolved is empirically unsupported. Philosophical implications in ethics will be incidentally considered.http://www.bec.ucla.edu/MacheryEvolutionOfMorality.pdf

Barbara KÃ¶nig - Cooperation and Social Selection - A Case Study of Communal Nursing in House Mice
2009-04-15 00:00
Barbara KÃ¶nig: University of Zurich Institute of ZoologyIn addition to sexual selection, selection resulting from social interactions in contexts other than mating can be a potent evolutionary force. Such social selection processes are facilitated whenever individual fitness varies as a result of any form of social interactions. The choice of social partners for communal care of young is such a situation in which interactants potentially experience fitness variance. We combine lab experiments with field data to investigate the existence and impact of female social partner choice and the potential for social selection to occur in the communally breeding wild house mouse (Mus domesticus). Female house mice display non-random preferences, and social partner choice yields significant fitness benefits. This suggests that interactions among females are subject to social selection processes, driving the evolution of female traits.http://www.bec.ucla.edu/Konig.pdf
