Stephanie Brown, University of Michigan  (website)

Can the Selfish Gene Make a Selfless Human?

Theories of social bonds are predominately "self-centered" because they assume that individuals maintain close relationships with others in order to get rewards such as sex, security, feelings of love, social support, etc. In this talk I consider a gene-centered alternative that is grounded in Hamilton's notion of inclusive fitness. This alternative suggests that social bonds evolved to support altruism between individuals who were interdependent for fitness. According to this gene-centered account, social bonds enable the suppression of self-interest, as opposed to the pursuit of self-interest, when individual needs conflict with inclusive fitness concerns. I will summarize evidence that supports this gene-centered alternative, and address concerns and controversies.

Alice Eagly, Northwestern University  (website)

Social Structural Origins of Sex Differences in Human Mating: Cross–Cultural, Cross–Temporal, and Individual Variation in Mate Preferences

Sex differences in human mating have attracted the attention of evolutionary psychologists and scientists representing other evolutionary viewpoints because of the importance of mating preferences to reproduction and to fitness outcomes. These differences provide an excellent arena for comparing the predictions of differing theories. The social structural approach has analyzed comparisons of mate preferences across cultures, across time periods, and across individuals within cultures. These studies show that mating practices are flexibly emergent from bio-social factors reflecting the evolved physical attributes and related behaviors of men and women within social and ecological contexts.

Mark Frank, University at Buffalo, State University of New York  (website)

Deception and Lying: The Case of the Human Being

Human beings tell lies quite frequently. Lies are defined as deliberate attempts to mislead, without prior consent of the target; this differs from the broader category of deception, which does not require a deliberate attempt to mislead. This presentation will discuss the latest research on lying, what behavioral signals accompany it, why these behaviors would be apparent, and whether humans can identify them in face to face contexts. It will be argued that these behaviors are constituents of other communicative systems evolved for other more mainstream communicative tasks, and thus are probabilistically related to deception, and not some "Pinocchio" response that is exclusive to deception. The implications of this for human lie catching, particularly in the age of terrorism, will then be discussed.

Christine Garver–Apgar  (website)
Steven W. Gangestad, Randy Thornhill, Robert D. Miller, and Jon J. Olp
University of New Mexico, Albuquerque

MHC Alleles, Sexual Responsivity, and Unfaithfulness in Romantic Couples

Preferences for mates that possess genes dissimilar to one's own at the major histocompatibility complex (MHC), a polymorphic group of loci associated with the immune system, have been found in mice, birds, fish, and humans. These preferences may help individuals choose genetically compatible mates and may adaptively function to prevent inbreeding or increase heterozygosity and thereby immunocompetence of offspring produced through the mateship. MHC–dissimilar mate preferences may influence the psychology of sexual attraction. We investigated whether MHC–similarity among romantically involved couples (N = 48) predicts aspects of their sexual relationship. All women in our sample normally ovulated, and 3 MHC alleles were typed for each person. As the proportion of MHC alleles couples shared increased, women's sexual responsivity to partners decreased, women's number of extra-pair sexual partners increased, and women's attraction to men other than primary partners increased, particularly during the fertile phase of their cycles.

Jeffry Simpson, University of Minnesota  (website)

Marshaling Evidence for Special Design

Despite Williams' (1966) call for special design evidence to support hypothesized adaptations, many tests of evolutionary principles and ideas do not offer clear evidence for the special design features of purported adaptations. In this talk, I will discuss how evidence for special design features of conjectured psychological adaptations can be marshaled, highlighting recent work suggesting the existence of a specific fear module in primates.

Peter Todd, Indiana University  (website)

Mate search and other decisions in a decision–shaped world

In many social domains, we face the challenge of how to make decisions 
in environments that are themselves shaped by the decisions of ourselves 
and others. Searching for a mate is a particularly pressing, and 
evolutionarily important, instance of this challenge, where the choices 
made by competitors, and by potential mates, both have an impact on what 
strategy an individual searcher should use. Nonetheless, simple 
strategies based on quickly setting and using an aspiration level can 
lead to adaptive mate choices, but only if the strategy takes into 
account the particular structure of the task environment. In this talk, 
such strategies are developed in simulation, and empirical approaches to 
testing them in action are described, including the use of 
population-level data from demographic databases and individual–level 
data from speed-dating sessions.

Wendy Wood, Duke University  (website)

Social Structural Origins of Sex Differences in Human Behavior: Bio–Social Theory of the Interactions Between Evolved Dispositions and Environmental Conditions

Variability in sex differences across cultures and ecologies reflects humans' sensitivity to local circumstances. Humans are endowed with this flexibility because they evolved in diverse environments with changeable conditions that impinged in differing ways on their reproduction and survival. Accommodating successfully to such ecological and social challenges required behavioral flexibility, enabled by an evolved capacity for social learning and the cumulation of culture. Such evolved capacities allow humans to produce solutions dynamically to the problems of reproduction and survival. These solutions are evident in the varying social roles of men and women given local ecologies and social conditions. Gendered social roles reflect the costs and benefits that men and women perceive to accompany activities associated with reproduction and survival in a given setting. These costs and benefits are framed by the sexes' evolved physical attributes and related behaviors, especially women's childbearing and nursing of infants and men's greater size, speed, and upper–body strength.