John A. Bargh, Yale University  (website)

Unconscious Behavioral Guidance Systems

Behavioral priming effects occur when a mental representation is passively or unobtrusively activated by an external stimulus and then influences behavior in line with its content. For example, perceiving another person's behavior makes it more likely you will behave the same way, and thinking about your mother makes it more likely you will pursue the goals you have regarding her. Both of these effects (and others) occur unconsciously with no role played by conscious choice or intent (and often without awareness as well). Understanding why all of these various priming effects occur has led to the hypothesis that they have evolved to solve the basic adaptive question: what to do next? That is, the various priming effects on behavior can explain the origin of the mysterious pre-conscious 'impulses' to action as noted – but not explained – by William James, Gazzaniga, Libet, Wegner, and others over the past 100 years.

Elsa Ermer, University of California Santa Barbara  (website)

Coalitional Support and the Regulation of Welfare Tradeoff Ratios

Natural selection acting on our ancestors is expected to have equipped the human mind with evolved mechanisms that were designed to register the impact of an individual's behaviors on the welfare of others, and to regulate their choices based on estimates of this impact. The logic of animal conflict indicates that organisms should use cues of relative formidability as one factor in determining how much weight to put on another animal's welfare. For humans, the ability to form coalitions allows individual formidability to be augmented by support from others. Accordingly, the human mind should be designed to register the magnitude of an individual's coalition–derived formidability, and to use this magnitude to increase the amount of resources ceded to such an individual––the coalitional support hypothesis. Across two very different experimental economics games, men's decisions were consistent this idea, suggesting coalitional support is an important regulator of human judgment and decision–making.

Vladas Griskevicius, Arizona State University  

The Many Shades of Rose–Colored Glasses: Discrete Positive Emotions and Persuasion

How do positive feelings influence persuasion? The answer might initially appear simple. Much research already shows that positive affect leads people to process information in a simpler or more heuristic manner. Good moods are also known to produce the "rose–colored glasses effect," whereby positive affect leads everything from products to political candidates to be evaluated more positively. In my research I use a functional framework of positive emotion to examine how persuasion is influenced by different positive emotions, including pride, enthusiasm, contentment, sexual desire, amusement, and awe. In contrast to traditional notions, I find that not all positive affect is created equal. For example, positive feelings can lead to more heuristic or to more systematic processing of persuasive messages, depending on the specific positive emotion that a person is feeling. Similarly, positive affect may or may not enhance product attractiveness, depending on which positive emotion a person is feeling and the type of product being evaluated. For example, while pride enhances the attractiveness of public display products such as watches or shoes, pride does not enhance the attractiveness of basic home products such as beds or dishwashers. Overall, specific positive emotions lead to emotion–specific effects that are consistent with functional accounts of discrete positive emotions.

Kerri L. Johnson, University of California Los Angeles  (website)

Gender Counts: Why Perceived 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 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 "just one look."

Hilly Kaplan, University of New Mexico  (website)

A Theory of Lifespan Evolution and Its Implications for Nuero–senescence

There is converging evidence suggesting that the evolved use life of the human body is about 65 to 75 years of age, under the conditions under which our ancestors lived. This paper will review this evidence and present a model of gene-environment interaction to explain lifespan evolution, in general, and the human lifespan in particular. Our data show that the number of dependent grandchildren in which older people can invest declines dramatically after age 65. After their last child is born, both men and women gradually shift their resource transfers from dependent children to dependent grandchildren, nevertheless still producing an economic surplus. As the number of dependent grandchildren declines towards zero, older people appear to reach the point at they no longer produce a surplus, just at the age they experience high rates of morbidity and mortality. The paper concludes with a discussion of convergence in senescence across different physiological systems, including psychological function, suggesting that the age schedule of cognitive decline will be similar to physiological senescence under traditional conditions.

Dario Maestripieri, University of Chicago  (website)

Macachiavellian Intelligence: How Rhesus Macaques and Humans Have Conquered the World

Humans and rhesus macaques are the most successful primates on this planet. In part, their evolutionary success may be the result of ecological characteristics they share with other "weed" species: an omnivorous diet, high mobility and tendency to colonize new environments, and ability to reproduce under a wide range of environmental conditions. In part, their success may be due to their intelligence, and particularly their social intelligence. In this presentation, I will explore the hypothesis that humans and rhesus macaques share a set of similar social tendencies, collectively referred to as Macachiavellian intelligence, characterized by a gregarious, aggressive, and stress-resilient temperament, high individualism and social opportunism, tendency to form despotic and nepotistic social systems in which individuals compete for high status and power and genuine altruism is exhibited only toward close kin, strong xenophobia, and high within–group cohesiveness under conditions of external threat. Rhesus macaques exhibit their Macachiavellian tendencies in any environment, whereas humans are most likely to exhibit such tendencies in capitalistic societies or when strong cultural influences on their behavior are reduced or eliminated (e.g.. under conditions of imprisonment or within military organizations). The Macachiavellian intelligence of humans and rhesus macaques likely arose by convergent evolution during long periods of intense within– and between–group competition in the evolutionary history of these species. Their Macachiavellian intelligence may have given humans and rhesus macaques an edge in the ecological competition with other related species, and also served as a selective engine for the further evolution of larger brains and complex intelligence.

Geoffrey Miller, University of New Mexico  (website)

The Evolutionary Social Psychology of Consumer Behavior

Evolutionary psychology is starting to illuminate the world of consumer behavior, marketing, and product design - but that world can also reveal many new things about human nature. In this talk, I'll review some key ideas from my forthcoming book 'Faking fitness: The evolutionary origins of consumer narcissism', and discuss three recent empirical studies. (1). Asking people to think about possible mates leads men to invest more money in conspicuous consumption (spending on high-cost luxuries), whereas it leads women to invest more time in blatant benevolence (conspicuous altruism) (Griskevicius et al., 2007). (2) Players in the online game 'World of Warcraft' are willing to spend a huge price premium at public auctions for weapons that look larger, cooler, and rarer, even controlling for all objective attributes of the weapons (Mendenhall & Miller, in prep) (3) Professional lap-dancers earn much more money per shift when they are in estrus (maximum–fertility days just before ovulation), than when they are in the luteal or menstrual phases of the cycle, but taking the contraceptive Pill eliminates this estrus earnings boost (Miller, Tybur, & Jordan, 2007). In each case, an evolutionary psychology theory plus empirical investigation of consumer spending patterns yields new insights into human social and sexual strategies.

Randy Thornhill, University of New Mexico  (website)

The Functional Design and Phylogeny of Women's Dual Sexuality: Estrus and Extended Sexuality

Recent research questions the conventional wisdom about the evolution of women's sexuality. Women have two functionally distinct sexualities. At the fertile phase of the cycle, women prefer male traits that may mark superior genetic quality. At infertile cycle phases, women prefer men willing to invest resources in a mate. Women's peri–ovulatory sexuality is homologous with estrus in other vertebrates and estrus likely arose first in the species ancestral to vertebrates. Thus, contrary to conventional wisdom, women have not lost estrus, and human estrus likely functions to get a sire of superior genetic quality, which is the evolved function of estrus throughout the vertebrates. Women's sexuality outside estrus is extended sexuality. It appears to function, as in other taxa with this type of sexuality, to get material benefits from males. Also contrary to conventional wisdom, men perceive and respond to women's estrus, including by increased mate guarding. Men's response is limited compared to other vertebrate males, implying co-evolutionary history of selection on females to conceal estrus from men and selection on men to detect it. Research indicates that women's concealed estrus is an adaptation to conditionally copulate with men other than the pair–bond partner. Women's sexual ornaments–the estrogen–facilitated features of face and body–appear to be honest signals of individual quality pertaining to future reproductive value (R. Thornhill and S. W. Gangestad. In press. The Evolutionary Biology of Human Female Sexuality. Oxford Univ. Press).