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Behavior, Evolution, and Culture
Speaker Series Mondays 12:00-1:30, Haines Hall 352, UCLA
Fall Quarter 2007 1 Oct: Mark Kleiman UCLA Department of Public Policy Maximizing cooperation while minimizing punishment
The threat of punishment can facilitate cooperation
by discouraging defection and aggression. Because punishment is scarce,
costly, and painful, optimal enforcement strategies will minimize the amount
of actual punishment required to effectuate deterrence. If potential
offenders are deterrable, increasing the conditional probability of
punishment (given violation) can reduce the amount of punishment actually
inflicted, by "tipping" a situation from its high-violation
equilibrium to its low-violation equilibrium. Compared to random or
"equal opportunity" enforcement, dynamically concentrated sanctions
can reduce the punishment level necessary to tip the system. 8 October: Mary Towner UC Davis Department of Anthropology Investigating cultural macroevolution and trait transmission in the Western North American Indian database
Cultural traits are distributed across human
societies in a patterned way. Study of the mechanisms whereby cultural traits persist and change over time is key
to understanding human cultural diversity. For more than a century, a central question has engaged
anthropologists interested in the study of cultural trait variation—what is the source of cultural variation? More
precisely, are cultural traits transmitted primarily from ancestral to descendant populations (through vertical
transmission or inheritance) or between contemporary, typically neighboring, populations (through horizontal
transmission or diffusion), or do they emerge as independent innovations? In addition, do traits in different
domains, such as kinship and family, subsistence and settlement, or material culture, show different
transmission patterns? Addressing such questions has proven to be methodologically challenging. Drawing on a
research collaboration with Dr. Monique Borgerhoff Mulder and Dr. Mark N. Grote, I will show how autologistic
models can overcome some of the limitations of previous approaches by placing the different transmission
mechanisms on a more equal analytical footing. These models can explicitly incorporate the structural
links between societies, with geographical proximity being used as a proxy for horizontal transmission, and
linguistic classification being used as a proxy for vertical transmission. I illustrate the method with an
application to cross-cultural data from the Western North American Indian database, a sample of 172 societies
for which detailed ethnographic surveys were conducted in the early 20th century.
Alternative autologistic models are estimated through MCMC simulations and then compared based on Akaike Information
Criterion. The results suggest that the best models will almost always incorporate both vertical and
horizontal processes. 15 Oct: Gian Gonzaga
eHarmony.com Is there an “I” in “We”? Relationships are often studied through one of two
questions. How does the relationship benefit the individual and/or how does
the relationship benefit the dyad? This talk will address the challenges of
balancing what is good for me, what is good for my partner, and what is good
for the relationship. It will then review a series of studies that shows that
self-interest is sometimes best served by promoting the success of the
relationship, even at the momentary expense of the self. 22 Oct: Andrew Shaner UCLA VA
Hospital Age at onset of schizophrenia: Evidence of
a latitudinal gradient
Variation in the age at onset of a multifactorial disease often reflects variation in cause. In this talk, I show a linear latitudinal gradient in the mean age at onset of schizophrenia in 13 northern-hemisphere cities, ranging from 25 years old in Cali, Columbia (at 4 degrees north) to 35 years old in Moscow, Russia (at 56 degrees north). This striking association has not been previously reported. I consider several explanations, including the effects of pathogen stress, natural selection, sexual selection, migration, life-history profiles, or some combination of these factors, and I propose a test of competing causal hypotheses. 29 Oct: Rob Kurzban Penn Psychology Morality is (at
least) a Three-Player Game
Substantial debate remains about the ultimate and
proximate explanations for why people choose to punish third parties, individuals involved in interactions
that have had and will have no direct effect on the punisher. Here, one particular type of third-party punishment
is explored, moralistic punishment, enduring a cost to inflict costs on an individual who has violated a perceived
moral norm. Results from a series of experiments suggest that 1) third-party punishment, at least in
these cases, is considerably less frequent and smaller in magnitude than would be expected from existing
models, 2) knowing that one will be observed in meting out moralistic punishment increases individuals’ willingness
to do so, and 3) inducing emotions such as empathy has systematic effects on both moralistic
punishment and compensating victims of moral wrongs. These findings are discussed in the context of possible evolved functions of moral
psychology, focusing on the centrality of moralistic punishment for
understanding the nature of the moral game being played. 5 Nov: Kerri Johnson UCLA
Communication Studies Gender Counts: Why perceptions of masculinity and
femininity are as important as the cues that convey them In the 1950s, Doris Troy famously sang, “Just one look...that’s all it took,” 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 ofa 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 cuesand 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 perceptionsof masculinity and femininity provide the evaluative interpretation of biologically relevant cues - engendering rapid and ready judgments of attractiveness from “just one look.” 12 Nov: Veteran’s Day No
speaker
19 Nov: Richard Lippa Cal
State University, Fullerton Department of Psychology Sex Differences in Sexuality,
Personality, and Cognitive Abilities across 53 Nations: Probing Evolutionary and
Sociocultural Explanations BBC data from 53 nations and from more than 200,000 participants provide new insights into sex differencesin: (1) sexual traits (e.g., sex drive and sociosexuality), (2) mate preferences (e.g., the value assigned tophysical attractiveness, intelligence, honesty in a mate), (3) personality traits (e.g., extraversion,agreeableness, neuroticism, people-versus-thing orientation), and (4) cognitive abilities (mental rotationability, line angle judgment ability). Predictions that follow from social role theory—e.g., that sex differenceswill be larger in countries with stronger gender roles—received little support in the BBC data. In contrast,predictions that follow from evolutionary theories—e.g., that there will be consistent sex differences acrossnations, which do not covary with nations’ levels of gender equality—received support for many of theassessed sex differences. Results for sociosexuality (sex differences were larger in patriarchal than ingender-egalitarian nations, and women’s sociosexuality varied more across nations than men’s did) wereconsistent with a hybrid model—that cultural factors influence women’s sociosexuality more than men’s andare superimposed on biologically-based sex differences. Results for sex differences in trait SDs (e.g., acrossnations, women varied more than men did in sex drive and extraversion; men varied more than women did inagreeableness and mental rotation scores) also tended to support biological theories over social structuraltheories, except in the case of sociosexuality, where results were consistent with a hybrid model thatassumed cultural influences superimposed on biological predispositions: for sociosexuality, men were morevariable than women in patriarchal countries, but the reverse was true in gender-egalitarian countries. Read the paper 26 Nov: Russ Poldrack UCLA Psychology How, and what, can neuroimaging tell us about the mind? It has become common practice amongst neuroimaging researchers to infer the presence of mentalprocesses 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 mentalprocesses. I will present evidence suggesting that these associations are often weak, providing littleevidence in favor of the reverse inference. I will also discuss general strategies by which one can useneuroimaging to inform theories of mental processes. 3 Dec: Michael Arbib USC Neuroscience New Sign Languages and Language Evolution Human language is far more than speech and its derivatives such as writing. Human signed languages likeAmerican Sign Language are fully expressive human languages, and speakers normally accompany theirspeech with facial and manual gestures. Thus any theory of language evolution must address these integralroles that manual signs and gestures play today. What are the capabilities of the human brain that make itpossible for humans to learn language while other creatures can not? How much structure must the socialenvironment offer a child to acquire language? We probe these questions by studying two sign languages ofrecent vintage. Nicaraguan Sign anguage developed in just 25 years while Al-Sayyid Bedouin Sign Languagedeveloped over at most 70 years, and are still developing. We examine the emergence and dynamics of theselanguages to advance discussion of what supports society offered to allow these communities to exploit thehuman brain’s readiness for language in novel ways.
Winter Quarter 2008
7 Jan: Roger Sullivan CSU
Sacramento, Anthropology, and UC Davis School of Medicine, Psychiatry
and Behavioral Sciences Revealing the paradox of drug reward in
human evolution
Neurobiological 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. 14 Jan: Afzal Upal Occidental Do we have religion because evolution favors opportunistic
learners? Cognitive
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. 21 Jan: Martin Luther King, Jr, Day No Speaker 28 Jan: Mark Collard Simon Fraser
University Archaeology Risk and
technological innovation in small-scale societies
4 Feb: Aaron Blaisdell UCLA Psychology and Brain Research Institute Intervention
and Causal Inferences in Rats I 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 (XßAàFood), 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 XàAàFood 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. 11 Feb: Steve Gangestad University of New Mexico Psychology Human Estrus:
Function and Phylogeny Broad, 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 “lost” estrus—a distinct fertile-phase sexuality—and
instead evolved “continuous” sexuality across the reproductive cycle, which functioned to “conceal” ovulation. Recent
research suggests that this assumption is wrong; women clearly do exhibit a distinct “fertile-phase”
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 “estrus,” 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 women’s fertility in fact not concealed? A general
reinterpretation of women’s purported “lost estrus,” 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. *Co-sponsored by The UCLA Interdisciplinary Relationship Science
Program and The UCLA Center for Society & Genetics 18 Feb: Presidents' Day No Speaker 25 Feb: John Mitani University of Michigan Anthropology Cooperation
in wild chimpanzees *Co-sponsored by The UCLA Interdisciplinary Relationship Science
Program 3 Mar: Jelmer Eerkens UC Davis Anthropology Material
culture evolution: an archaeological perspective on forces and rates of
change Laboratory 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. 10 Mar: Becky Frank UCLA Anthropology The role
of contingent reciprocity and market exchange in the lives of female olive
baboons The 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. *Co-sponsored by The UCLA Interdisciplinary Relationship Science
Program Spring Quarter 2008 31 Mar: Carel van Schaik Anthropological Institute & Museum, University of Zurich Dominance styles and male-male coalitions
among nonhuman primates and humans
Naturalistic 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-dominants’ 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. *Co-sponsored by The UCLA
Interdisciplinary Relationship Science Program 7 Apr: Sam Bowles Santa Fe Institute The Coevolution of Parochial Altruism and War Altruism -- benefiting fellow group members at a cost to oneself -- and parochialism – hostility toward individuals not of one’s own ethnic, racial or other group -- are common human behaviors. The intersection of the two – 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. *Co-sponsored by The UCLA Center for Society and Genetics Read the paper 14 Apr: Carol Padden UCSD and Mark Aronoff Stonybrook U Embodied cognition in an emerging
language: Al-Sayyid Bedouin Sign Language
We 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. *Co-sponsored
by The UCLA
Center for Society and Genetics 21 Apr: Gary Marcus NYU Psychology Kluge: The
Haphazard Construction of the Human Mind
In fields ranging from reasoning to linguistics,
the idea of humans as perfect, rational, optimal creatures is making a comeback – but should it be? Hamlet’s
musings that the mind was “noble in reason ...infinite in faculty” have their counterparts in recent
scholarly claims that the mind consists of an “accumulation of superlatively well- engineered designs” shaped by
the process of natural selection (Tooby and Cosmides, 1995), and the 2006 suggestions of Bayesian
cognitive scientists Chater, Tenenbaum and Yuille that “it 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 performance”, as well as in Chomsky’s recent suggestions that language is close “to what
some super-engineer would construct, given the conditions that the language faculty must satisfy”. 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 “superlative adaptation” is itself theoretically suspect, and ought to be considerably tempered by
recognition of what Stephen Jay Gould called “remnants of history”, 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. *Co-sponsored
by The UCLA Center
for Society and Genetics 28 Apr: Susan Perry UCLA Anthropology Social
learning about foraging strategies in wild capuchin monkeys. White-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 |
