Diana S. Fleischman

Evolutionary psychology: controversies, questions, prospects, and limitations

Evolutionary psychology has emerged over the past 15 years as a major theoretical perspective, generating an increasing volume of empirical studies and assuming a larger presence within psychological science. At the same time, it has generated critiques and remains controversial among some psychologists. Some of the controversy stems from hypotheses that go against traditional psychological theories; some from empirical findings that may have disturbing implications; some from misunderstandings about the logic of evolutionary psychology; and some from reasonable scientific concerns about its underlying framework. This article identifies some of the most common concerns and attempts to elucidate evolutionary psychologys stance pertaining to them. These include issues of testability and falsifiability; the domain specificity versus domain generality of psychological mechanisms; the role of novel environments as they interact with evolved psychological circuits; the role of genes in the conceptual structure of evolutionary psychology; the roles of learning, socialization, and culture in evolutionary psychology; and the practical value of applied evolutionary psychology. The article concludes with a discussion of the limitations of current evolutionary psychology.

Progesterone's effects on the psychology of disease avoidance: Support for the compensatory behavioral prophylaxis hypothesis

In the human menstrual cycle, luteal phase immunomodulation prevents the maternal immune system from attacking the half-foreign blastocyst should conception occur, thereby facilitating implantation and development. However, tolerance of the conceptus comes at the cost of increased vulnerability to infection. The compensatory behavioral prophylaxis hypothesis (Fessler, 2001; Fessler & Navarrete, 2003) holds that evolved psychological mechanisms enhance avoidance of potential contaminants during periods of reproductive immunomodulation so as to decrease the likelihood of infection. Because such immunomodulation is triggered by progesterone, this hormone is predicted to correspondingly enhance behavioral prophylaxis and the motivational states underlying it. We investigated specific domains of disease avoidance psychology in a nonclinical sample of women (n=120) by measuring salivary progesterone in naturally cycling women. We find that progesterone correlates directly with the degree to which women report emotions, thoughts, and behaviors consonant with enhanced prophylaxis.

Race Bias Tracks Conception Risk Across the Menstrual Cycle

Although a considerable body of research explores alterations in womens mating-relevant preferences across the menstrual cycle, investigators have yet to examine the potential for the menstrual cycle to influence intergroup attitudes. We examined the effects of changes in conception risk across the menstrual cycle on intergroup bias and found that increased conception risk was positively associated with several measures of race bias. This association was particularly strong when perceived vulnerability to sexual coercion was high. Our findings highlight the potential for hypotheses informed by an evolutionary perspective to generate new knowledge about current social problems—an avenue that may lead to new predictions in the study of intergroup relations.

Oral Contraceptives Suppress Ovarian Hormone Production

In “The Cutest Little Baby Face: A Hormonal Link to Sensitivity to Cuteness in Infant Faces,” Sprengelmeyer et al. (2009) reported results from three fascinating studies designed to test humans’ ability to discriminate among infants on the basis of cuteness. The first study indicated that women of reproductive age are superior to men and older women in this regard, and the second study revealed that premenopausal women perform better than age-matched postmenopausal women. Sprengelmeyer et al. compellingly argued that these findings, taken together, strongly indicate that female reproductive hormones (specifically, the two principal hormones, estrogen and progesterone) play a role in sensitivity to cuteness. The authors sought to explore this possibility in a third study, in which they tested women who were taking exogenous hormones for contraception. They found that such women differentiate cuteness in infant faces better than naturally cycling women do. The authors interpreted this result as consonant with their hypothesis about the contribution of estrogen and progesterone to cuteness detection—that oral contraceptives “raise hormone levels artificially” (p. 149). Although hormonal differences between the two groups may have been responsible for this difference, it is unlikely that the effect was due to elevated levels of estrogen1 and progesterone in the women using oral contraceptives. Contrary to many researchers’ beliefs, oral hormonal contraceptives actually suppress ovarian production of these hormones.

Women’s Disgust Adaptations

It is well accepted that disgust is an emotion whose main function is to motivate away from cues of disease or potential contamination. Although this adaptive problem is one that both men and women face, women tend to have heightened disgust sensitivity and higher frequency of psychopathologies like obsessive-compulsive disorder that have heightened disgust sensitivity as a core symptom. Women have faced unique selection pressures such as pregnancy, changes in immunity over the menstrual cycle, higher obligate parental investment, and heavier disease burden from sexually transmitted infection that have contributed to their increased disgust sensitivity compared to men. First, this chapter outlines the development of a theoretical framework around the evolution and function of disgust. Next, it reviews sex differences in disgust sensitivity as well as the modulation of disgust sensitivity. Finally, sexual disgust and recent work investigating how disgust and sexual arousal reciprocally influence one another are reviewed including the contribution of disgust to sexual disorders and expression.

Sensor recorded changes in rates of hand washing with soap in response to the media reports of the H1N1 pandemic in Britain

Objectives To examine how the frequency of information regarding a real disease threat influences hand washing with soap. Design and setting The authors installed wireless devices in highway service station lavatories in England to record the proportion of individuals washing hands with soap from May 2009 to January 2010. Participants Participants were users of mens and womens toilets. Combined there was an average of 6800 participant entrances into the lavatories daily. Primary outcome measure The primary outcome measure is the proportion of soap usage to the number of entries into the lavatories. Results Hand-washing rates were positively related to both H1NI coverage in blogs and the news; however, these relationships were stronger for men than for women. Conclusions Hand washing with soap increases proportionally to the frequency of media key words related to H1N1. Womens hand washing was more strongly associated with incidence of media keywords than mens.

Disgust versus Lust: Exploring the Interactions of Disgust and Fear with Sexual Arousal in Women

Sexual arousal is a motivational state that moves humans toward situations that inherently pose a risk of disease transmission. Disgust is an emotion that adaptively moves humans away from such situations. Incongruent is the fact that sexual activity is elementary to human fitness yet involves strong disgust elicitors. Using an experimental paradigm, we investigated how these two states interact. Women (final N=76) were assigned to one of four conditions: rate disgust stimuli then watch a pornographic clip; watch a pornographic clip then rate disgust stimuli; rate fear stimuli then watch a pornographic clip; or watch a pornographic clip then rate fear stimuli. Women’s genital sexual arousal was measured with vaginal photoplethysmography and their disgust and fear reactions were measured via self-report. We did not find that baseline disgust propensity predicted sexual arousal in women who were exposed to neutral stimuli before erotic content. In the Erotic-before-Disgust condition we did not find that sexual arousal straightforwardly predicted decreased image disgust ratings. However, we did find some evidence that sexual arousal increased self-reported disgust in women with high trait disgust and sexual arousal decreased self-reported disgust in women with low trait disgust. Women who were exposed to disgusting images before erotic content showed significantly less sexual arousal than women in the control condition or women exposed to fear-inducing images before erotic content. In the Disgust-before-Erotic condition the degree of self-reported disgust was negatively correlated with genital sexual arousal. Hence, in the conflict between the ultimate goals of reproduction and disease avoidance, cues of the presence of pathogens significantly reduce the motivation to engage in mating behaviors that, by their nature, entail a risk of pathogen transmission.

Menstrually related mood disorders and a history of abuse:moderators of pain sensitivity.

OBJECTIVE Women with a menstrually related mood disorder (MRMD) have substantially higher rates of physical and sexual abuse and are more sensitive to experimental pain stimuli than women without a MRMD. For the first time, this study examined pain sensitivity and hormonal correlates in women with a MRMD and in non-MRMD controls as a function of abuse history. METHODS A total of 126 women (63 with MRMD, 34 with an abuse history; and 63 non-MRMD, 31 with an abuse history) were evaluated for: (1) sensitivity to cold pressor and forearm ischemic pain and (2) basal plasma cortisol and norepinephrine (NE) concentrations. Exploratory analyses examined relationships between plasma cortisol and NE concentrations and pain sensitivity. RESULTS Women with a MRMD and an abuse history showed increased sensitivity to both cold pressor and ischemic pain and lower basal cortisol concentrations, an effect not seen in the women without a MRMD. In all women, the expected relationship between greater plasma cortisol concentration and reduced sensitivity to pain was observed, whereas NE predicted pain sensitivity only in women with a MRMD. CONCLUSIONS Menstrually related mood disorder status moderates the effect of a history of abuse on pain sensitivity. The results also suggest that the hypocortisolemia documented in the women with a MRMD and an abuse history may contribute to their greater sensitivity to noxious pain stimuli. This study adds to a growing body of evidence suggesting that a history of abuse may identify a clinically distinct subgroup of women with a MRMD.

An evolutionary behaviorist perspective on orgasm

Evolutionary explanations for sexual behavior and orgasm most often posit facilitating reproduction as the primary function (i.e. greater rate of fertilization). Other reproductive benefits of sexual pleasure and orgasm such as improved bonding of parents have also been discussed but not thoroughly. Although sex is known to be highly reinforcing, behaviorist principles are rarely invoked alongside evolutionary psychology in order to account for human sexual and social behavior. In this paper, I will argue that intense sexual pleasure, especially orgasm, can be understood as a primary reinforcer shaped by evolution to reinforce behavior that facilitates reproductive success (i.e. conception through copulation). Next, I will describe an evolutionary account of social shaping. In particular, I will focus on how humans evolved to use orgasm and sexual arousal to shape the social behavior and emotional states of others through both classical and operant conditioning and through both reproductive and non-reproductive forms of sexual behavior. Finally, I will describe how orgasm is a signal of sensitivity to reinforcement that is itself reinforcing.

Trade-Offs, Individual Differences, and Misunderstandings about Evolutionary Psychology.

Replies to comments on Evolutionary psychology: Controversies, questions, prospects, and limitations (see record 2010-02208-001) by Confer et al. The purpose of which was to clarify the logic of evolutionary psychology and clear up some of the more common misunderstandings about it. In this response, we address the key points raised by the commentators.