1. Adaptive Biases in Social Judgment. We have asked why humans seem to have such error-prone judgment and decision-making strategies. Our work tests the general hypothesis that some of them could be adaptive (see EMT, below).
   
   
2. Ovulatory Shifts in Women's Preferences, Thoughts, and Behaviors. Women’s heavy investment in reproduction has produced selection for a discriminating sexual psychology. The window of fertility within a woman's cycle is also fleetingly brief. These two observations suggest that women have mating adaptations that are sensitive to or contingent on fertility status. In our research we are testing hypotheses about the design of these adaptations.
   
   
3. Evolved Relationship Defenses. We investigate how people maintain their long-term mating relationships. We have asked, for example, how people in committed relationships resist the temptation of attractive others.
   
   
4. Flirtation, Sexual Signaling, and Cross-Sex Communication. We study common misunderstandings between the sexes, particularly in the context of dating and courtship (see EMT, below).
   
   

Members of the Evolutionary Psychology Laboratory include students from Psychology, Communication Studies, and Anthropology. If you are interested in getting involved, please contact us to inquire about opportunities. Haselton also advises graduate students in the Department of Psychology. Prospective graduate students should contact Dr. Haselton for more information.

According to Error Management Theory (EMT; e.g., Haselton, 2001; Haselton & Buss, 2000, 2003), natural selection will often design judgment and decision making adaptations that are systematically biased. These adaptations are not designed to be maximally accurate; rather, they are designed to err in the direction of lower survival or reproductive cost.

Consider the design of smoke alarms (Nesse & Williams, 1998), which are often biased toward making false alarms. The cost of having a slightly error-prone system is small in comparison to the benefit of knowing that missed fires will be extremely rare.

We have proposed that the same general principle should apply to the design of the mind. When the costs of a false positive error are recurrently greater than the costs of a false negative error, natural selection builds adaptations biased toward a false negative error, a miss. When the costs are reversed, selection biases the adaptation toward making the opposite error, a false alarm.

We have applied EMT to human courtship signaling. EMT predicts that men possess a bias toward over-inferring sexual interest in women on the basis of ambiguous cues, such as a smile. We propose that this bias minimized missed reproductive opportunities in ancestral environments, and hence it should evolve instead of mechanisms with high thresholds for inferring sexual interest or those designed for maximum accuracy. According to another EMT hypothesis, the cost structure was reversed for ancestral women when they developed inferences about men’s interest in commitment. Some initial skepticism about a man’s commitment would have been more beneficial (and less costly) than falling victim to deceptive signals of commitment intent. As a result, we expect commitment inferences in women that are biased toward false negative errors (misses), at least in the early phases of courtship.

This research may have implications for understanding sexual harassment. Recently, a dozen female employees of the Safeway supermarket chain filed complaints over the store’s service-with-a-smile policy. The policy required employees to make eye contact and smile at customers as they completed their shopping transactions. Consumers often misconstrued this friendly behavior as a sign of sexual interest.