Center for Behavior, Evolution, and Culture

Tatsuya Kameda - Emotional Functioning and Socio-Economic Uncertainty: Is "Hikikomori" an Indigenous Cultural Pathology in Japan?
2008-11-24 00:00 (America/Los_Angeles)
Tatsuya Kameda: Hokkaido University Department of Behavioral ScienceFeeling and expressing emotions appropriately in the right context is an essential component of social behavior. It has been suggested that emotional functioning has been weakened among contemporary Japanese youth, who exhibit acute social withdrawal, a “cultural pathology” known as Hikikomori (Hattori, 2005; Zielenziger, 2006). Assuming that Hikikomori is at least partially caused by socio-economic uncertainties faced by younger generations, we predicted that the syndrome is not confined to a clinical subpopulation but should be manifested by even undiagnosed youth, though in moderated form, as a negative function of their family socio-economic status (SES). Results from an emotion-sampling study â€“ in which participants’ reported their momentary emotional states 12 times per day for one-week during the course of their daily lives â€“ and a laboratory experiment â€“ which measured psycho-physiological responses to emotional stimuli â€“ both supported this prediction. Implications of these findings for the well-being of youth in well-developed, post-industrial societies are discussed.

John Mikhail - Universal Moral Grammar: Theory, Evidence, and Future Research
2008-11-17 00:00
John Mikhail: Georgetown LawScientists from various disciplines have begun to focus renewed attention on the psychology and biology of human morality. One research program that has recently gained attention is universal moral grammar (UMG). UMG seeks to describe the nature and origin of moral knowledge by using concepts and models similar to those used in Chomskyâ€™s program in linguistics. This approach is thought to provide a fruitful perspective from which to investigate moral competence from computational, ontogenetic, behavioral, physiological, and phylogenetic perspectives. In my talk, I first outline a framework for UMG and describe some of the evidence supporting it. I then discuss some initial findings of a related study in comparative law that seeks to determine how certain norms, such as the prohibition of homicide, are codified and interpreted in several hundred jurisdictions around the world. The studyâ€™s main finding, the apparent universality or near-universality of specific justifications and excuses, lends further support to UMG. It also raises novel questions for cognitive science, broadly construed, including neuroethics, behavioral economics, evolutionary psychology, and legal anthropology.http://papers.ssrn.com/abstract=1163422

Noah Goldstein - The Constructive, Destructive, and Reconstructive Power of Social Norms
2008-11-10 00:00
Noah Goldstein: UCLA Anderson School of ManagementSocial norms can be powerful drivers of human behavior, which means that communicators who can properly harness norms hold in their hands a powerful tool for persuasion. If utilized properly, communicators can effectively convey such norms in ways that motivate individuals to engage in positive, constructive behaviors that benefit not only those individuals themselves but society as a whole. However, even thoughtful and well meaning communicators can convey norms ineffectivelyâ€”or worse, elicit a negative, destructive backfire effect that may exacerbate an already unappealing situation. Yet, even in such instances, when a certain social norm leads individuals to perform destructive behaviors, other types of social norms can be employed to mitigate the negative influence of that norm. I will discuss how, when, and why different kinds of social norms play constructive, destructive, and even reconstructive roles in motivating human behavior.

John Alcock - Why I Am Still a Single-Minded Adaptationist
2008-11-03 00:00
John Alcock: Arizona State University Department of Life SciencesI will review why I became an adaptationist and continue to believe that the theory of natural selection as amended by W.D. Hamilton supplies us with all we need in order to understand all aspects of animal behavior, including that of our own species. I will examine the state of the study of animal behavior when I entered the field and the effects of the revolution that occurred around this time thanks to Hamilton and George C. Williams. I will present my take on the challenges to the “adaptationist programme” that have occurred since 1966. These challenges include Gould and Lewontin’s famous attack in the 1970s but also the current attempt to revive group selection led by David S. Wilson and E.O. Wilson. In addition, I will explain why the cultural evolution approach to human behavior has only limited usefulness. I hope to be still in one piece when I am finished.

Brooke Scelza - Bush Forager, Shop Forager: Production and Consumption Behavior in a Group of Western Desert Aborigines
2008-10-27 00:00
Brooke Scelza: UCLA Department of AnthropologyAustralian Aborigines in the Western Desert have gone through a nutritional transition in the last 50 years; moving from a diet of mainly indigenous â€œbush foodsâ€ acquired during daily foraging trips to one that includes store-bought products delivered directly to community shops. Although store-bought foods are more convenient, their availability fluctuates due to poor road conditions, community budget constraints and food spoilage. Small game and certain species of widely available large game, on the other hand, require more energy to acquire, but have a relatively consistent rate of return. An evolutionary perspective on diet choice suggests that people should make choices that will optimize their daily caloric intake and respond quickly to resource depletion. In this paper I will look at the consumption of foraged and store-bought foods in one Martu Aboriginal community to better understand issues of diet choice, foraging time allocation and risk management. I will then place this case study within a broader framework to demonstrate how an evolutionary approach can illuminate new ways of thinking about human behavior related to diet and nutrition.

Gary Charness - Three Field Experiments on Procrastination and Willpower / Territoriality and Gender in the Laboratory
2008-10-20 00:00
Gary Charness: UC Santa Barbara Department of EconomicsWe conducted three field experiments to investigate how people schedule and complete tasks, providing some of the first data concerning procrastination and willpower under financial incentives. In our first study, we paid students $95 if they completed 75 hours of monitored studying over a five-week period. We also required people to meet interim weekly targets in one treatment, but not in the other. In a second study, the task consisted of answering of multiple-choice questions on seven consecutive days, with staggered start dates and an endogenous task ordering (tasks varied by number of questions). In our third study, participants answered 20 multiple-choice questions over two consecutive days, varying whether this was during the week or on the weekend. Participants were required to complete an easy or difficult Stroop test (used by psychologists to deplete willpower) on the first day, before any questions could be answered. We find evidence of procrastination and willpower depletion/replenishment, as well as evidence suggesting a self-reputation interpretation. And yet the behavioral interventions we used led to outcomes that surprised us in all three studies, although these outcomes are largely consistent with the standard neo-classical model.http://www.bec.ucla.edu/Charness_Procrastination.pdf

Jessica Lynch Alfaro - Biological And Cultural Evolution In Capuchin Monkeys: Mapping Behavioral Traditions Onto A Cebus Molecular Phylogeny
2008-10-13 00:00
Jessica Lynch Alfaro: UCLA Center for Society and GeneticsDespite growing interest in capuchin monkeys as model organisms for social learning and cultural evolution, comparative evolutionary study of Cebus behavioral traits across field sites and species have been impeded by the lack of a robust phylogenetic hypothesis for the group. Here I present the first molecular phylogeny of Cebus and use it as a framework to study the evolution of social and foraging traditions, including anointing behaviors and tool use. Using tissue collected from museum specimens of wild-caught capuchins of known provenance across Latin America, I sequenced portions of three mtDNA genes (12s, 800 bp; cytB, 307 bp; d-loop, 435 bp) and reconstructed phylogenetic relationships using likelihood and Bayesian methods. My data revealed Cebus as a monophyletic genus composed of distinct tufted and non-tufted clades. In contrast to morphological studies, the data revealed that C. albifrons and C. libidinosis are each paraphyletic. Genetic diversity in the tufted capuchin clade was concentrated in the Atlantic forest, and the Amazonian tufted capuchins were nested as a subclade within Atlantic forest capuchins. I estimated divergence times within Cebus using external fossil calibrations under the assumption of a relaxed molecular clock and used this timetree to test whether social and foraging traditions have evolved more quickly in tufted versus non-tufted clades. This study provides both the first detailed molecular phylogeny for Cebus and new approaches to examining rates of behavioral evolution for different traits across capuchin populations. Conclusions from this study have implications for the prioritization of conservation funding and data collection.

Russell Jackson - What You See is not What You Get: Evolved Distance Perception Adaptations
2008-10-06 00:00
Russell Jackson: CSU San Marcos Department of PsychologyDistance perception is among the most ubiquitous psychological phenomena known. Humans utilize distance estimation during all waking hours and even when sleeping. Distance perception likely takes place to this same extent in most other animals and distance perception also occurs in many non-animal species.
Furthermore, distance perception is one of the oldest researched topics in modern behavioral science. The most commonly cited founding of modern psychological science dates to Wundtâ€™s investigations of distance perception in the late 1800s. Distance perception is among the most common mental tasks and has been investigated since the founding of psychology.
Unfortunately, some of the most important questions about distance perception remain unanswered. How and why do we perceive distances the way that we do? Why is distance perception sometimes wildly inaccurate? Why are there such big individual differences in distance perception? We have yet to answer to these questions well.
Recent application of evolution by natural selection has yielded novel insights to these questions. I will discuss recent evidence from several empirical studies that discovered large magnitude visual effects, including illusions, in everyday distance perception. These illusions appear to occur constantly throughout human experiences and reach magnitudes of nearly a factor of two. These findings also illuminate a potential cause for the most prevalent, but least acknowledged, finding of all distance perception research.

Brian Skyrms - Evolution of Signaling Systems With Multiple Senders and Receivers
2008-09-29 00:00
Brian Skyrms: UC Irvine Department of Logic & Philosophy of ScienceSender-Receiver games are simple, tractable models of information transmission. They provide a basic setting for the study the evolution of meaning. It is possible to investigate not only the equilibrium structure of these games, but also the dynamics of evolution and learning â€“ with sometimes surprising results. Generalizations of the usual binary game to interactions with multiple senders, multiple receivers, or both, provide the elements of signaling networks. These can be seen as the loci of information processing, of group decisions, and of teamwork.

Gyorgy Gergely - Beyond Imitative Learning: The case for Natural Pedagogy Evolutionary Mechanisms of Cultural Knowledge Transmission in Humans
2008-06-02 00:00
Gyorgy Gergely: Central European University, Budapest, Stanford Center
for Advanced Studies in Behavioral SciencesHuman minds construct cultural products that form part of the environmental niche to which new generations of human minds must adapt. A remarkable feature of cultural transmission is that infants fast-learn a vast amount of cultural skills very early on even when they cannot yet fully grasp their relevant causal, functional, intentional, or adaptive properties. This represents an apparent paradox: how can such cognitively â€˜opaqueâ€™ cultural forms be successfully transmitted and maintained across generations? Are there specialized cognitive mechanisms evolved to make efficient intergenerational transfer of such cultural knowledge possible?
The dominant view holds that it is the capacity for imitative learning that serves the evolutionary function of
cultural transmission in humans. Iâ€™ll argue, however, that presently proposed models of imitative learning face
the problem of â€˜relevance-blindnessâ€™ as they lack appropriate selection mechanisms to differentiate relevant
(to be re-enacted and learned) from non-relevant, incidental to be disregarded) aspects of observed
behaviors. â€˜Relevance-blindâ€™ imitative copying would be a wasteful and inefficient transmission mechanism
likely to lead to distorted reproduction and eventual extinction of useful cultural innovations over the
generations.
Iâ€™ll suggest that the emergence of cognitively opaque cultural skills during hominin evolution and the
consequent need for their efficient intergenerational transmission created evolutionary pressure leading to the
selection of a new type of â€˜relevance-guidedâ€™ social-communicative learning mechanism of mutual design:
the system of â€˜Natural Pedagogyâ€™ (NP) (Gergely & Csibra, 2006). On the naÃ¯ve â€œteacherâ€™sâ€ side, NP involves an
instinctual inclination to ostensively manifest – and guide the ignorant â€œlearnerâ€™sâ€ inferences to identify â€“
relevant cultural information to be fast-learned. On the naÃ¯ve â€œlearnerâ€™sâ€ side, NP involves evolved sensitivity
to â€˜ostensiveâ€™ (e.g., eye-contact, contingent reactivity, or infant-directed speech) and referential (e.g., gaze-shift
or pointing) cues that are interpreted to signal the otherâ€™s communicative intention to manifest new, relevant
(and generalizable) cultural knowledge about a referent (and its kind). Such cues trigger a receptive learning
attitude to fast-learn ostensively manifested contents even when they are cognitively opaque to the
learner. Iâ€™ll present evidence to support the NP hypothesis from our infancy studies testing the basic
assumptions of the theory about the nature of early cultural learning in humans in a number of different
knowledge domains.

Katie Hinde - Magnitude, Sources, and Consequences of Individual Variation in Milk Production in Rhesus Macaques
2008-05-19 00:00
Katie Hinde: UCLA AnthropologyLactation represents the greatest post-natal cost of mothering in primates and numerous studies have
established that variation in maternal condition is associated with infant growth, development, health, and
survival. Presumably the effects of maternal condition are mediated through milk output during lactation,
however this relationship remains poorly understood. Here I present the first systematic investigation of the
magnitude, sources, and consequences of individual variation in motherâ€™s milk for an Old World monkey.
Rhesus macaques produce dilute milk typical of the primate order, however there was substantial variation
between mothers, as well as within mother, over lactation in milk composition and yield, and therefore the milk
energy available for the infant. Maternal life history was associated with milk yield and milk energy density was
biased in favor of sons, especially first-born sons. Infants that had higher available milk energy at one month
of age were characterized by higher activity levels and greater confidence at 3.5 months of age suggesting that
motherâ€™s milk may serve as a nutritional cue that calibrates infant behavior and temperament to maternal
and/or environmental conditions. These results, obtained from a well-fed captive population, demonstrate that
small differences between mothers can have important implications for lactational investment and infant
outcomes.

Peter Todd - Investigating mate search with simulation and speed-dating
2008-05-12 00:00
Peter Todd: U of Indiana Cognitive Science, Informatics, and Psychological and Brain SciencesThe choice of a mate is not only one of the most important decisions in our lives, but also one of the most difficult, fraught by lack of knowledge of the options to come and inability to return to options already passed by. How do we make this challenging sequential choice, at the same time we are trying to convince someone else to choose usâ€”and more specifically, how do we decide when our search is over? To find out, we could follow a set of individuals through multiple relationships over an extended period of timeâ€”or we can speed things up: We can build simulated mate-seekers who embody plausible decision rules for searching for partners, and see how they fare in an artificial mating market, comparing their behavior to that of aggregated humans. We can also speed up human mate-seekers themselves, by having them participate in speed-dating events and observing their searches as they meet and interact with a succession of potential partners. With these methods we are testing a satisfying search model that adjusts mate aspiration levels lower after failed relationships and higher after successful ones. We are also able to test other hypotheses about the kinds of mate choices people make, and how well matched they end up being.

Debra Lieberman - It's all relative: Altruism, sexual aversions, and morality
2008-05-05 00:00
Debra Lieberman: U of Hawaii PsychologyMechanisms for detecting kin rely on cues that correlated with relatedness in ancestral environments to adaptively regulate mate selection and altruistic effort. For siblings, one potential cue, proposed by Edward Westermarck, is co-residence duration. Another cue that would have been highly predictive of siblingship is seeing one’s mother caring for a newborn. Data from a series of investigations show that these two cues regulate the development of altruistic motivations, sexual aversions, and, as a by-product, moral sentiments relating to incest. Revisiting the natural experiments that fueled the discussion over how sexual aversions and moral sentiments develop, I show that these two cues also explain the data from the Taiwanese minor marriages. Furthermore, I provide new evidence that childhood co-residence predicts altruistic tendencies, sexual aversions, and moral sentiments in individuals raised in the communal fashion of the Israeli Kibbutzim.

Susan Perry - Social learning about foraging strategies in wild capuchin monkeys.
2008-04-28 00:00
Susan Perry: UCLA AnthropologyWhite-faced capuchin monkeys are best known for their innovation and traditions in the domain of social
communication; however, social learning appears to play a role in the acquisition of their foraging techniques
as well. In this talk, I explore several lines of evidence indicating social influence in food processing
techniques. Several foods are processed differently at different sites that are similar both genetically and
ecologically. Within social groups, those monkeys who spend more time together are also more likely to
share the same foraging technique. There is also evidence that monkeys bias their social learning
opportunities to preferentially observe models who are foraging on rare or hard-to-process foods, thus
providing useful information on what to eat and how to eat it. Developmental studies yield evidence for a
conformity bias in use of food processing techniques, even for individuals who have already learned both of
two possible techniques.

Gary Marcus - Kluge: The Haphazard Construction of the Human Mind
2008-04-21 00:00
Gary Marcus: NYU PsychologyIn fields ranging from reasoning to linguistics, the idea of humans as perfect, rational, optimal creatures is
making a comeback â€“ but should it be? Hamletâ€™s musings that the mind was â€œnoble in reason …infinite in
facultyâ€ have their counterparts in recent scholarly claims that the mind consists of an â€œaccumulation of
superlatively well- engineered designsâ€ shaped by the process of natural selection (Tooby and Cosmides,
1995), and the 2006 suggestions of Bayesian cognitive scientists Chater, Tenenbaum and Yuille that â€œit
seems increasingly plausible that human cognition may be explicable in rational probabilistic terms and that,
in core domains, human cognition approaches an optimal level of performanceâ€, as well as in Chomskyâ€™s
recent suggestions that language is close â€œto what some super-engineer would construct, given the
conditions that the language faculty must satisfyâ€.
In this talk, I will I argue that this resurgent enthusiasm for rationality is misplaced, for three reasons. First, I
will suggest that recent empirical arguments in favor of human rationality rest on a fallacy of composition,
implicitly but mistakenly assuming that evidence of rationality in some (carefully analyzed) aspects of cognition
entails that the broader whole (i.e. the human mind in toto) is rational. In fact, establishing that some particular
aspect of cognition is optimal (or perfect, or near optimal) is not tantamount to showing that the system is a
whole is; current enthusiasm for optimality overlooks the possibility that the mind might be suboptimal even if
some (or even many) of the components of cognition have been optimized. Second, I will argue that there is
considerable empirical evidence (most well-known, but rarely given due attention in the neo-Rationalist
literature) that militates against any strong claim of human cognitive perfection. Finally, I will argue that the
assumption that evolution tends creatures towards rationality or â€œsuperlative adaptationâ€ is itself theoretically
suspect, and ought to be considerably tempered by recognition of what Stephen Jay Gould called â€œremnants of
historyâ€, or what might be termed evolutionary inertia.
I will close by suggesting that mind might be better seen as what engineers call a kluge: clumsy and
inelegant, yet remarkably effective.

Carol Padden & Mark Aronoff - Embodied cognition in an emerging language: Al-Sayyid Bedouin Sign Language
2008-04-14 00:00
Carol Padden & Mark Aronoff: UCSD, Stonybrook UWe report here on work we have carried out with colleagues Wendy Sandler and Irit Meir on an emerging sign
language, Al-Sayyid Bedouin Sign Language (ABSL). ABSL developed de novo in a small closed community
of Bedouins which is now in its third generation of signers. In this talk, we show how a new human language
is assembled over a relatively short period of time. In this language, the body emerges as a primary signifier,
figuring prominently in the form of verbs, particularly in grammatical notion of subject. Broadly, we find that the
iconicity of the body and space around the body interacts with emerging grammatical structures, including
word order and morphology, resulting in a complex story about the deployment of physical, human resources
in the service of natural language grammars.

Sam Bowles - The Coevolution of Parochial Altruism and War
2008-04-07 00:00
Sam Bowles: Santa Fe InstituteAltruism — benefiting fellow group members at a cost to oneself — and parochialism â€“ hostility toward
individuals not of oneâ€™s own ethnic, racial or other group — are common human behaviors. The intersection of
the two â€“ which we term parochial altruism — is puzzling from an evolutionary perspective because altruistic or
parochial behavior reduces ones payoffs by comparison to what one would gain by eschewing these
behaviors. But parochial altruism could have evolved if parochialism promoted inter-group hostilities and the
combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic
analysis and agent-based simulations show that under conditions likely to have been experienced by late
Pleistocene and early Holocene humans, neither parochialism nor altruism is viable singly, but by promoting
group conflict, they could have evolved jointly. http://www.bec.ucla.edu/Bowles.pdf

Carel van Schaik - Dominance styles and male-male coalitions among nonhuman primates and humans
2008-03-31 00:00
Carel van Schaik: Anthropological Institute & Museum, University of ZurichNaturalistic data on nonhuman primates show that the degree of despotism among males in primate groups
is predicted by the degree to which mating access to females can be monopolized. Degree of despotism
should affect other aspects of male behavioral strategies, such as how long top-dominantsâ€™ tenure is, how
top-dominance is achieved and which groups are targeted for dispersal, as well as the feasibility and
profitability of different kinds of male-male coalitions. Primate data support these predictions. This primate
model is then applied to human foragers. A fundamental difference is caused by the presence of weaponry.
When opportunities for despotism increase, violent coalitionary takeovers of top dominance and the formation
of elites emerge.

Becky Frank - The role of contingent reciprocity and market exchange in the lives of female olive baboons
2008-03-10 00:00
Becky Frank: UCLA AnthropologyThe goal of this project was to examine the dynamics of exchange among female baboons and test
predictions derived from a biological market model of grooming. Evolutionary theory predicts that cooperation
among nonkin will be limited to reciprocating partners who monitor the balance of trade within their
relationships in order to prevent cheating. But primates may be cognitively limited to negotiating balanced
reciprocity over very short time scales. If so, then trade might be regulated in a biological market, where
supply and demand determines the value of an exchange, and individuals choose to trade with the partner
offering the highest value. Individuals maximize their immediate benefits without having to monitor the
balance of their exchanges over time. When demand for a partner or commodity is greater than the supply,
individuals compete for access to the preferred partner by raising the price they are willing to pay. Applied to
primate grooming exchanges, a market model predicts that females will balance the amount of grooming they
trade within single bouts when all partners offer similar value. In some cases, partners can offer other
valuable benefits and will trade those with who ever offers the most grooming in return. Thus, females are
predicted to trade grooming for access to resources when feeding competition is elevated and rank
differences translate to differential foraging success. Females are also predicted to trade grooming with
mothers of young infants in exchange for access to the infant. I tested these predictions in a group of 16 adult
female olive baboons in Chololo, Kenya. In this troop, females only reciprocated within the same grooming
bout 34% of the time and balanced their grooming more evenly over many bouts than within single bouts.
Non-mothers preferentially groomed mothers of young infants, but did not compete for access to infants by
raising their grooming offers to mothers as the availability of infants declined. When feeding conflict within
dyads was high, females provided additional grooming to their higher ranking partners, but they do not spend
more time co-feeding in return. These results suggest that female baboons are capable of monitoring their
exchanges over time and can trade across some currencies, but it is not clear that market pricing explains the
observed patterning of exchange.

Jelmer Eerkens - Material culture evolution: an archaeological perspective on forces and rates of change
2008-03-03 00:00
Jelmer Eerkens: UC Davis AnthropologyLaboratory experiments and ethnographic studies show that many aspects of human culture, particularly
information, can change quickly in the course of transmission. The archaeological record indicates much
more conservative rates of change, at least for material culture. Is there common theoretical ground between
the micro- and macro- scales? This paper considers some of the factors that affect culture change and the
rate at which material culture, and variation therein, might change in the archaeological record. As well, it
explores the micro-macro perspectives.

John Mitani - Cooperation in wild chimpanzees
2008-02-25 00:00
John Mitani: University of Michigan Anthropology

Steve Gangestad - Human Estrus: Function and Phylogeny
2008-02-11 00:00
Steve Gangestad: University of New Mexico PsychologyBroad, ambitious conceptualizations of the evolution of human sexuality (and accompanying unique social,
developmental, and intellectual adaptations) offered by anthropologists and biologists over the last half
century have been, almost universally, rooted in a foundational assumption: That women evolutionarily â€œlostâ€
estrusâ€”a distinct fertile-phase sexualityâ€”and instead evolved â€œcontinuousâ€ sexuality across the reproductive
cycle, which functioned to â€œconcealâ€ ovulation. Recent research suggests that this assumption is wrong;
women clearly do exhibit a distinct â€œfertile-phaseâ€ sexuality. This talk addresses a number of questions about
the conceptual significance and theoretical meaning of these recent findings: (a) Is this fertile phase sexuality
appropriately referred to as human â€œestrus,â€ and, if so, on what basis?; (b) What selection pressures shaped
fertile-phase sexuality; was it shaped through direct selection or through indirect selection (i.e., as
byproduct)?; (c) Recent evidence also suggests that men respond differently to women as a function of their
phase (typically, being more attracted to women in their fertile phases than women in their luteal phases); is
womenâ€™s fertility in fact not concealed? A general reinterpretation of womenâ€™s purported â€œlost estrus,â€
continuous sexuality, and concealment of fertility will be offered. The theme that a proper understanding of
human sexuality requires a broader comparative perspective than is often brought to bear in evolutionary
psychology is stressed.

Aaron Blaisdell - Intervention and Causal Inferences in Rats
2008-02-04 00:00
Aaron Blaisdell: UCLA Psychology and Brain Research InstituteI report a series of experiments showing that rats appear to make causal inferences in a basic task that taps
into core features of causal reasoning. (1) They derived predictions of the outcomes of interventions after
passive observational learning of different kinds of causal models. After learning through Pavlovian
observation that Event A was a common cause of Events X and Food (XÃŸAÃ Food), rats predicted Food when
presented with Event X as a cue but discounted the alternative cause A when they generated X by means of a
lever press. (2) Rats showed evidence of reality monitoring. After learning an XÃ AÃ Food causal chain where
X was a tone and A was a light, when tested on X rats expected A to occur. But when A did not occur during
testing, rats did not expect food. By hiding the light during testing on X, however, rats showed no disruption of
food expectancy, suggesting that rats understood that A was unobservable. (3) Finally, we present evidence
that rats treated their actions as special in causal learning. Discounting of a previous cause was only
observed with interventions but not with other observable events; rats were capable of flexibly switching
between observational and interventional predictions; and discounting occurred on the very first test trial.
These results confirm causal-model theory but refute associative theories.http://www.bec.ucla.edu/Blaisdell_Paper.pdf

Mark Collard - Risk and technological innovation in small-scale societies
2008-01-28 00:00
Mark Collard: Simon Fraser University Archaeology

Afzal Upal - Do we have religion because evolution favors opportunistic learners?
2008-01-14 00:00
Afzal Upal: OccidentalCognitive anthropologists such as Pascal Boyer have argued that religious concepts are minimally
counterintuitive and that this gives them mnemic advantages. I will ague that people have the memory
architecture that results in such concepts being more memorable because it makes them better learners
which gives them an evolutionary edge over their competitors. I will show how such benefits emerge in the
real-time processing of comprehending narratives such as folk tales. This model suggests that memorability
is not an inherent property of a concept as Boyer appears to assume; rather it is a property of the concept, the
context in which the concept is presented, and the background knowledge that the comprehendor possesses
about the concept. The model predicts how memorability of a concept should change if the context containing
the concept were changed. I will also present the results of experiments carried out to test these predictions.http://www.bec.ucla.edu/Upal_Paper.pdf

Roger Sullivan - Revealing the paradox of drug reward in human evolution
2008-01-07 00:00
Roger Sullivan: CSU Sacramento, Anthropology, and UC Davis School of Medicine,
Psychiatry and Behavioral SciencesNeurobiological models of drug abuse propose that drug use is initiated and maintained by
rewarding feedback mechanisms. However, most commonly used drugs are plant neurotoxins
that evolved to punish, not reward, consumption by animal herbivores. Reward models therefore
implicitly assume an evolutionary mismatch between recent drug-profligate environments
and a relatively drug-free past in which a reward center, incidentally vulnerable to neurotoxins,
could evolve. In contrast, emerging insights from plant evolutionary ecology and the genetics
of hepatic enzymes, particularly cytochrome P450, indicate that animal and hominid taxa have
been exposed to plant toxins throughout their evolution. Specifically, evidence of conserved
function, stabilizing selection, and population-specific selection of human cytochrome P450
genes indicate recent evolutionary exposure to plant toxins, including those that affect animal
nervous systems. Thus, the human propensity to seek out and consume plant neurotoxins
is a paradox with far-reaching implications for current drug-reward theory. We sketch some
potential resolutions of the paradox, including the possibility that humans may have evolved
to counter-exploit plant neurotoxins. Resolving the paradox of drug reward will require a
synthesis of ecological and neurobiological perspectives of drug seeking and use.http://www.bec.ucla.edu/Sullivan.pdf

Michael Arbib - New Sign Languages and Language Evolution
2007-12-03 00:00
Michael Arbib: USC NeuroscienceHuman language is far more than speech and its derivatives such as writing. Human signed languages like
American Sign Language are fully expressive human languages, and speakers normally accompany their
speech with facial and manual gestures. Thus any theory of language evolution must address these integral
roles that manual signs and gestures play today. What are the capabilities of the human brain that make it
possible for humans to learn language while other creatures can not? How much structure must the social
environment offer a child to acquire language? We probe these questions by studying two sign languages of
recent vintage. Nicaraguan Sign anguage developed in just 25 years while Al-Sayyid Bedouin Sign Language
developed over at most 70 years, and are still developing. We examine the emergence and dynamics of these
languages to advance discussion of what supports society offered to allow these communities to exploit the
human brainâ€™s readiness for language in novel ways.http://www.bec.ucla.edu/ArbibPaper.doc

Russ Poldrack - How, and what, can neuroimaging tell us about the mind?
2007-11-26 00:00
Russ Poldrack: UCLA PsychologyIt has become common practice amongst neuroimaging researchers to infer the presence of mental
processes from activation in particular parts of the brain. The validity of this practice, which I refer to as
“reverse inference”, depends upon how selectively specific brain regions are associated with specific mental
processes. I will present evidence suggesting that these associations are often weak, providing little
evidence in favor of the reverse inference. I will also discuss general strategies by which one can use
neuroimaging to inform theories of mental processes.

Richard Lippa - Sex Differences in Sexuality, Personality, and Cognitive Abilities across 53 Nations: Probing Evolutionary and Sociocultural Explanations
2007-11-19 00:00
Richard Lippa: Cal State University, Fullerton Department of PsychologyBBC data from 53 nations and from more than 200,000 participants provide new insights into sex differences
in: (1) sexual traits (e.g., sex drive and sociosexuality), (2) mate preferences (e.g., the value assigned to
physical attractiveness, intelligence, honesty in a mate), (3) personality traits (e.g., extraversion,
agreeableness, neuroticism, people-versus-thing orientation), and (4) cognitive abilities (mental rotation
ability, line angle judgment ability). Predictions that follow from social role theoryâ€”e.g., that sex differences
will be larger in countries with stronger gender rolesâ€”received little support in the BBC data. In contrast,
predictions that follow from evolutionary theoriesâ€”e.g., that there will be consistent sex differences across
nations, which do not covary with nationsâ€™ levels of gender equalityâ€”received support for many of the
assessed sex differences. Results for sociosexuality (sex differences were larger in patriarchal than in
gender-egalitarian nations, and womenâ€™s sociosexuality varied more across nations than menâ€™s did) were
consistent with a hybrid modelâ€”that cultural factors influence womenâ€™s sociosexuality more than menâ€™s and
are superimposed on biologically-based sex differences. Results for sex differences in trait SDs (e.g., across
nations, women varied more than men did in sex drive and extraversion; men varied more than women did in
agreeableness and mental rotation scores) also tended to support biological theories over social structural
theories, except in the case of sociosexuality, where results were consistent with a hybrid model that
assumed cultural influences superimposed on biological predispositions: for sociosexuality, men were more
variable than women in patriarchal countries, but the reverse was true in gender-egalitarian countries.http://www.bec.ucla.edu/Lippa_sex_drive_and_sociosexuality_UCLA%5B1%5D.doc

Kerri Johnson - Gender Counts: Why perceptions of masculinity and femininity are as important as the cues that convey them
2007-11-05 00:00
Kerri Johnson: UCLA Communication StudiesIn the 1950s, Doris Troy famously sang, â€œJust one look…thatâ€™s all it took,â€ implying that attraction can begin
with little more than a glance. Contemporary research in person construal generally corroborates this
observation, but debate continues about precisely how physical cues come to convey attractiveness. One
unresolved question centers on whether objective indices of masculinity and femininity predict perceived
attractiveness. Attempts to answer this question have been frustrated by contradictory results. In this talk, I
will argue that masculinity and femininity are better defined as subjective judgments of the gender-typicality of
a trait, not as objective indices of sexual dimorphism. I will present data suggesting that once sex
categorization has occurred, sexually dimorphic traits are interpreted to be either masculine or feminine, the
typicality of which strongly predicts perceptions of attractiveness. Masculine men and feminine women are
perceived as attractive; feminine men and masculine women are not. This perspective has several important
implications. First, this perspective implies that the accuracy or error in the cognitive representations of sexual
dimorphism will systematically skew gender judgments and thereby affect perceived attractiveness. At times,
this may result in preferences that appear quite extreme by objective standards. At other times, this may even
yield preferences for traits that are gender atypical by objective standards. Second, this perspective
acknowledges the importance of cultural and ecological factors as moderators of the relation between cues
and attractiveness. Perceptions of masculinity/femininity are likely to vary systematically with culture and
ecology, and perceived attractiveness should vary accordingly. In sum, my talk will describe how perceptions
of masculinity and femininity provide the evaluative interpretation of biologically relevant cues – engendering
rapid and ready judgments of attractiveness from â€œjust one look.â€http://www.bec.ucla.edu/Johnson&Tassinary(2007).pdf
