MORNING POSTER SESSION
Did Religion Evolve to Prop Up Humans' Self-Control Capacities?
Many of the recent changes in humans' patterns of food production and social interaction have been predicated on self–control. For instance, increased self–control would have been required to avoid too–steeply discounting the longer–later metabolic benefits that would have come from the transition from a seminomadic foraging lifestyle to a sedentary, agrarian subsistence pattern. Likewise, as Rachlin has argued, cooperative dilemmas of all sorts are resolved more optimally when the future (or uncertainty about others' behavior) is not discounted too steeply. Thus, to the extent that greater self–control benefited humans both in terms of food production and social cooperation, any psychological mechanisms that support the development of self–control may have been visible to genetic or cultural selection. We believe that religious belief may be one such psychological mechanism. If this is the case, then it would be likely that religion is linked with self–control or self–regulation more generally, among contemporary humans. We outline a model of how religious cognitions and behaviors may lead to improvements in self–control and how they may influence the various elements in Carver and Scheier's (1998) model of self–regulation. We also present data gathered from undergraduate students that demonstrate that self–reported religiousness is associated with self–report measures of self–control and conscientiousness, and that it is in this way distinct from non–sectarian measures of spirituality. Finally, we report evidence that the association of religion and self–control is responsible for several of religion's associations with behaviors such as delinquency among adults, and drug use and precocious sexual behavior among adolescents.
Reasoning About Disease
Infectious diseases–and the people who are infected by them–can pose a substantial fitness threat. It follows that people may be highly sensitive to the presence of individuals who are potentially contagious, and that this hypersensitivity may manifest in the domain of rule–based reasoning. We conducted a study designed to examine three specific questions: (1) Is rule–based reasoning facilitated (relative to a meaningful but threat–irrelevant control condition) when presented in a context pertaining to the detection of contagious others? (2) How does this reasoning compare to that observed in a different threat–detection context (cheater detection)? (3) To what extent is reasoning in the contagion–threat–detection context (and the cheater–detection context) cognitive effortless, relative to reasoning in control condition? The study (N = 185) employed four variations of a Wason card–sorting task, and also included a manipulation of cognitive load. Results revealed: (1) Reasoning was facilitated (compared to the control task) on the contagion–threat–detection task. (2) The magnitude of this facilitation effect was almost equivalent to that associated with the cheater–detection task. And (3) whereas cognitive load impaired reasoning on the control task, cognitive load resulted in no impairment whatsoever on the contagion–threat– or cheater–detection tasks. These results extend work on the adaptive context of rule–based reasoning. Future research should address whether facilitated reasoning in contagion–threat–detection contexts reflects a particular form of precautionary reasoning, a byproduct/overgeneralization of cheater–detection reasoning, or a psychologically (and perhaps evolutionarily) distinct mode of facilitated rule–based reasoning.
No One Wants to Date a Person Who is Desperate: The Effect of Information about Past Breakups on Future Dating Success
In contrast to many other species, mate value in humans is a complex mixture of both observable characteristics and behaviors and traits that are less easily discernible such as kindness, intelligence, loyalty, etc (e.g. Buss, 1994). One potentially valuable source of insight into mate value might be information about the person's past success or failure in romantic relationships. To test this possibility, the current study used on–line personal advertisements. Subjects were exposed to a brief hypothetical dating advertisement containing relatively benign information and asked to rate how much they would like to be in a relationship with the person who placed the ad. They were then given additional information, including the critical information about why the person's last relationship ended. This was varied to show the person as rejecting (my last partner was great, but I though I could find someone closer to my ideal), rejected (I was deeply in love with my last partner, but he/she dumped me and I can't figure out why) or ambiguous in that the person chose not to answer the question. As predicted, ratings dropped significantly for the person who was rejected. Somewhat surprisingly, the positive information did not simply increase ratings, and showed some suggestive sex differences. Declining to answer the question about how one's past relationship ended also produced surprising effects, with women being particularly bothered by this lack of information.
Estrogen Level Predicts Women’s Self-Perceived Physical Attractiveness and Romantic Relationship Motivations
High estrogen levels are a sign of a woman's reproductive health. Previous research has proposed that physical attractiveness is a cue to health and fertility in women (Thornhill & Grammer, 1999) and has found that estrogen levels are predictive of objectively–observed facial attractiveness (Law Smith et al., 2006). However, evidence of a relationship between estrogen and self–perceived body and facial attractiveness and mating motivations has yet to be established. We collected salivary samples (n=87) from normally cycling women at various points across the menstrual cycle. On the day the salivary assay was taken, participants completed self-perceived desirability scales and provided subjective reports of sexual and social motivations, and satisfaction with primary partner. It was found that estrogen level is positively associated with self–perceived attractiveness and is negatively associated with a woman's satisfaction with primary partner and may mediate her motivation to seek romance outside of her current relationship. Results provide support for the relationship between physical beauty and fertility and suggest that physiological mechanisms play a major role in guiding a woman's reproductive mating strategy.
Infectious Disease Prevalence and the Worldwide Distribution of Religiosity and Religions
Current reasoning suggests that religion is, in part, designed to serve as a social marker of group allegiance facilitating group coordination and cooperation, resolving the freeloader problem. We suggest differently. Religions serve as prophylactics to disease by reducing interaction with potentially infective others through the promotion of assortative sociality, mating and generally allying with individuals from a particular ingroup (ethnocentrism) and limiting interactions with outgroup members (xenophobia). This hypothesis is supported by our data that show religiosity (measured by two independent means) and the number of religions are correlated positively and highly with pathogen intensity throughout the countries of the world. This pattern remains after removing potential confounds such as economic development and democracy. Therefore, with higher pathogen intensity levels across the globe, we find a higher proportion of people adhering to the strict cultural norms associated with assortative sociality (religious doctrine) and a larger number of religions present. We suggest the relative intensity of infectious disease within the local environment can explain many aspects of the worldwide distribution of religiosity and religion diversity.
Monozygotic-Dizygotic-Virtual Twin Study of Tacit Coordination: Mechanism for Social Relatedness?
Explanations for why some partners can reach mutual goals more successfully than others has been of interest to researchers from diverse disciplines. Recently, some researchers have begun to assess evolutionary–based hypotheses and questions by observing the behaviors of genetically informative participants in experimental game situations. The present study was undertaken to determine if tacit coordination varies as a function of the genetic relatedness of the partners. Tacit coordination refers to circumstances in which "two parties have identical interests and face the problem not of reconciling interests but only of coordinating their actions for their mutual benefit when communication is impossible" (Schelling, 1960, p. 54). Participants included 53 monozygotic (MZ) twin pairs, 85 dizygotic (DZ) twin pairs, and 42 virtual twin (VT) (same–age unrelated siblings), ranging between 7 to 13 years of age. Twins were identified via the Fullerton Virtual Twin Study and TAPS (Twins, Adoptees, Peers and Siblings), a collaborative project between CSUF and the University of San Francisco. Each twin responded to a series of questions under individual and coordination conditions. As expected, MZ co–twins showed significantly greater overall agreement than both DZ co–twins and VT co–twins, using two scoring schemes (broad match and exact match). Pair gender was unrelated to the observed outcomes. The implications of these findings are considered with respect to mechanisms underlying the social relatedness between partners.
Effect of Context on Motor and Emotional Mimicry: Does Disliking Another Inhibit Mimicry?
There is conflicting evidence as to whether mimicry is strictly an unconscious reaction to perceptual cues or a more goal–directed process shaped by context. This study aims to examine whether the contexts of liking, disliking, and feeling neutral about another affects the degree to which people mimic that other's postures, movements and emotions. To create these contexts, participants were told that they may have to work with another person for the experiment, but that they could choose their potential lab partner. To help them in that choice, they received fictitious evaluations from the person's previous lab partner describing the potential partner as either a nice and good lab partner, a mean and bad lab partner, or a neutral and average lab partner. After participants indicated the likeability of the target and their desire to have this person as a lab partner, they watched the target tell either a sad or happy story. While the targets told an emotional story, they also periodically touched their faces, changed their postures, and nodded their heads. The participants were video-taped while they watched, and the tapes were independently coded for motor and emotional mimicry by the researcher and other volunteer raters who were blind to condition. The participants also filled out a brief survey assessing self–report emotional contagion and liking for the target after hearing the emotional story. We predict that liking another and wanting to affiliate with another will enhance mimicry of that other while disliking another will inhibit mimicry of that other as compared to feeling neutral about another.
Does Relative Rank Moderate Cheater Detection? Another Failure to Replicate
Cummins (1999) showed that performance on a Wason task is moderated by the relative rank of the participant and target, as predicted by dominance theory (Cummins, 1996) but not other extant theories about content effects in Wason–task performance. In two previous studies (Burkett & Kirkpatrick, 2001) comprising five distinct samples (total N = 829) and varying different procedures, we were unable to replicate the relative–rank effect using either Cummins' original materials or modified versions of them designed to eliminate a potential confound in her original design. In the present study we attempted to replicate the relative–rank effect using a different Wason–task scenario, in which relative–rank and social–contract content were independently manipulated in a 2x2 factorial design. In both a student sample (N = 298) and a community sample (N = 123), the social–contract manipulation evinced a significant effect but no rank effects were observed. As in our previous studies, overall performance levels varied predictably across our various samples and procedures, but the relative–rank effect was not replicated under any conditions. Discussion focuses on reasons why, apart from other potential merits of dominance theory, the relative–rank hypothesis may simply be incorrect.
Endocrine Responses of Young Men to Social Interactions with Young Women
Males of many nonhuman vertebrate species exhibit hormonal reactions to stimuli from potential mates. The present studies were designed to test replication of preliminary findings suggesting that human males may exhibit such reactions as well. In Experiment 1, young men (n = 115) provided saliva samples before and after either conversing with a woman confederate or sitting alone for 15 minutes. Changes from baseline in salivary testosterone concentrations were significantly greater among the men exposed to women, but only among subjects tested in the afternoon. In Experiment 2, male subjects (n = 99) interacted with either a male or a female confederate with saliva samples collected before and after these interactions and all experimental sessions conducted in the afternoon. Men who interacted with women exhibited significant elevations of testosterone relative to both their own baseline concentrations and to change scores among the men who interacted with other men. Women confederates' ratings of men's extraversion and degree of self–disclosure, furthermore, were positively correlated with changes in testosterone. In both experiments, in addition, changes in cortisol concentrations from baseline were significantly greater among men who spoke with women relative to men in the control conditions. The overall pattern of results supports the existence of neuroendocrine responses to potential mates in men that parallel those seen in nonhuman species and thereby suggest that phylogenetically conserved brain mechanisms may play a significant role in the regulation of human mating behavior.
Playboy Playmates, The Dow Jones, Consumer Sentiment, 9/11, and the Doomsday Clock: A Critical Examination of the Environmental Security Hypothesis
Do people's mate preferences change over time as a function of environmental conditions? What conditions precipitate such changes? Drawing on evolutionary social psychology, Pettijohn and Tesser's (1999) Environmental Security Hypothesis (ESH) proposes that during threatening times, people seek mates with more mature features. They found evidence that film actresses with more mature facial features were more popular during times of socio-economic hardship. Pettijohn and Jungeberg (2004) later showed that these effects generalized to body preferences, such that Playboy Playmates of the Year (PMOYs), who are determined partly by popularity, exhibited more mature anthropometric features (older, taller, heavier, larger waist–to–hip ratios [WHRs], lower body mass indexes [BMIs]) during times of hardship. Their composite measure of hard times, however, was highly heterogeneous; it was unclear weather the observed effects were driven by economic (unemployment) or existential (suicides, homicides) hardships. The present study critically examined the ESH by replicating and extending Pettijohn and Jungeberg while distinguishing between economic and existential threats. Forty–eight years (1960–2007) of PMOY anthropometric data (age, bust, waist, hips, height, weight, WHR, and BMI), two economic measures (Dow Jones industrial average [DJIA], consumer sentiment index [CSI]), and two existential threat measures (pre–versus–post–9/11 years, Doomsday Clock changes) were analyzed. Changes in economic indexes were either unassociated (CSI) or contrary (DJIA) to the ESH, such that taller, heavier women were preferred during prosperous markets. Supporting the ESH, increases in existential threats such as nuclear annihilation (Doomsday Clock) were related to older women and lower BMIs. The efficacy of the ESH is discussed.
What Rapunzel and Lady Godiva Have in Common: Using Hair Length as a Cue for Sexual Availability
People use a myriad of cues, both consciously and unconsciously, to detect the sexual availability of others. Previous research has shown that in addition to nonverbal communication (e.g., body language, flirting, etc) physical appearance can be used as a means to communicate an individual's sexual availability. Although there is research examining perceptions of clothing (Rupp & Wallen, 2007) and wedding rings (Black & Monteverde, 1975), there is no known research to date examining the influence of hair length as a cue for sexual availability. The purpose of this study was to examine whether people perceive the romantic availability of an individual based, in part, upon hair length. To this end a computer–based experiment was administered to 199 participants, of which 61% (N=121) were female and the average age was 19 years. Participants were randomly assigned to rate one of two sets of faces, with each set consisting of 4 female and 4 male targets. Each face was represented a single time in each of the sets, having long hair in one and short hair in the other. Participants rated the faces on a number of dimensions, including perceived attractiveness, promiscuity, and likelihood of being single. Multi–level analyses indicated that long hair was only a significant predictor of sexual availability for the female targets, even after accounting for perceptions of attractiveness. These and other findings are discussed in terms of their theoretical and practical ramifications, with consideration of both evolutionary and person perception theories.
Sexual Activity Reduces Women's Perceived Facial Attractiveness of Unknown Men
A study was conducted to assess whether sexual activity in the past 30 days, in particular penile–vaginal intercourse (PVI; which is associated with measures of relationship quality), influences the perception of the facial attractiveness of unknown men. Forty–five women reported the frequency of a variety of sexual behaviors and rated the facial attractiveness and friendliness of 20 men. Only orgasm from masturbation was found to be associated (inversely) with perceived friendliness. This finding may be reflective of the more anti–social attitude associated with more frequent masturbation. The results also show that women who engaged more frequently in most kinds of sexual behavior, not only PVI, considered unknown men to be less facially attractive. That is, more frequent sexual behaviors dampen the perceived attractiveness of other men and thereby may make women less susceptible to the lure of extra–pair mating.
An Adaptive Individual Difference Perspective on the Dark Triad
An evolutionary approach to personality psychology can enhance our understanding of individual differences. This study (N = 200) found that the Dark Triad was correlated with short–term mating, specifically, number of lifetime sex partners, sociosexuality, and degree of seeking a short–mate. This evidence suggests that the Dark Triad may be a suite of personality traits that could be described as adaptive individual differences, which help to promote reproduction. Evidence also suggests that men tend to be more sociopathic, narcissistic, and Machiavellian than women and that the correlations between the Dark Triad and short–term mating were stronger in men than women. This suggests that the Dark Triad are male–specific adaptive individual differences: aiding in men’s short–term sexual agenda more than women's. A path analysis demonstrates how the Dark Triad partially mediates the relationships between the sex of the participant and short–term mating behaviors, attitudes, and reproductive outcomes.
AFTERNOON POSTER SESSION
The Mere Presence of Opposite-Sex Others on Judgments of Desirability: Opposite Effects for Men and Women
Men's and women's mate preferences impose on each a unique set of adaptive problems that must be solved when judging the desirability of prospective mates. One potentially revealing source of information about an individual's desirability as a romantic partner is contained in the decisions made by same=–sex others. The present studies predicted that men's and women's desirability assessments would be affected in opposite ways when target persons were depicted with members of the target's opposite sex. Study 1 (N = 847), documented that women rated men more desirable when shown surrounded by women than when shown alone or with other men (a desirability enhancement effect). In sharp contrast, men rated women less desirable when shown surrounded by men than when shown alone or with women (a desirability diminution effect). Study 2 (N = 627) demonstrated analogous sexually-divergent effects for estimates of the desirability of same–sex competitors.
Pathogens, Personality and Culture: Disease Prevalence Predicts Worldwide Variability in Sociosexuality, Extraversion, and Openness to Experience
Previous research has documented cross–cultural differences in personality traits, but the origins of those differences remain unknown. We investigate the possibility that these cultural differences can be traced, in part, to regional differences in the prevalence in infectious diseases. Three specific hypotheses are deduced, predicting negative relationships between disease prevalence and (a) unrestricted sociosexuality, (b) extraversion, and (c) openness to experience. These hypotheses were tested empirically with methods that employed epidemiological atlases in conjunction with personality data collected from individuals in dozens of countries worldwide. Results were consistent with all three hypotheses: In regions that have historically suffered from high levels of infectious diseases, people report lower mean levels of sociosexuality, extraversion, and openness. Alternative explanations are addressed, and possible underlying mechanisms are discussed.
Test of a Costly Signaling Model of Human Apology
Social psychological research has identified determinants of effective apology (e.g., offering compensation), which are typically associated with some cost paid by the transgressor. We maintain that the cost associated with the apology is necessary to prove that the transgressor's honest intention to restore a harmonious relationship with the victim. This is consistent with the costly signaling model maintaining that honest messages should be entailed by some cost that is too costly for dishonest message senders to bear. Accordingly, it is expected that honest apology should be costly when the transgressor's exploitative intention is suspected and the victim considers termination of the relationship. On the other hand, apology may not necessarily be costly when it is transparent that the transgression was accidentally committed. To test these predictions, we conducted a vignette experiment, in which the participants imagined situations where their friend engaged in interpersonal transgressions. A 2 (exploitative intention: suspected vs. not-suspected) x 2 (apology: no cost vs. costly) x 3 (vignettes) factorial design with the last factor including repeated measures was employed. Two orthogonal planned comparisons collapsing the three vignettes revealed that participants' hypothetical anger was more effectively reduced by costly apology (1.23, SD=.80) than no costly apology (.52, SD=.54) when the exploitative intention was suspected, t(117)=3.61, p<.001, while it was equally reduced by no cost (.84, SD=.68) and costly apologies (.86, SD=.75) when the exploitative intention was not suspected, t(117)=.11, ns. These results will be discussed in the context of evolution of communication of intentions.
Inferring Coalitional Valuation from Costs Incurred
A growing body of theory and evidence indicates that the human mind has a suite of evolved specializations for regulating coalitional cooperation. We hypothesize that one subcomponent of this is an ability to infer and track the degree to which other individuals value the coalition. Further, whether individuals are categorized as a highly valuing the coalition should be based in part on the costs they are willing to incur. Consistent with this hypothesis, a series of experiments showed that (a) the mind does categorize as a separate "high–valuer" type those individuals who incur a relatively large cost, (b) this categorization leads to adaptive downstream inferences, and (c) these effects are not due to plausible alternatives, such as the mind categorizing by competence.
Emotions Coordinate Responses to Different Exclusions: Evidence for Distinct Exclusion-Response Mechanisms
Exclusion from social relationships is universally practiced and is universally painful. Any given exclusion event may result from one of several qualitatively distinct psychological motivations (e.g., avoidance of poor exchange partners, avoidance of pathogen–infected individuals). We hypothesize that these qualitatively distinct exclusion motivations have led to the co–evolution of qualitatively distinct exclusion–response mechanisms. These response mechanisms determine the nature of the exclusion and then generate an appropriate emotional response. This emotional response, in turn, orchestrates behavioral responses. In the present research, participants imagined being excluded from a coalition for either free–riding or pathogen infection, rated to what extent they would feel various emotions in this situation, and rated tactics they might use to regain acceptance in the group. As predicted, different types of exclusion a) led to distinct patterns of emotions, b) led to distinct patterns of behavioral tactics, and c) caused predictable links between emotional responses and behavioral tactics.
Functionally Relevant Faces Are More Accessible in Short-Term Memory
The faces of attractive females and angry outgroup males are relatively better recognized in studies of long term memory. These effects could arise from stronger encoding or greater resistance to decay or interference, each of which has different implications. We present three studies that demonstrate that attractive females and angry outgroup males are more accessible in the bottleneck of short–term memory. Using the Sternberg memory scanning paradigm, the first study found that attractive female faces were more rapidly and accurately retrieved from a recently learned set of faces when it also contained average–looking female faces. Memory sets of male faces showed no such accessibility benefits for the attractive faces. A second study using memory sets of either all attractive or all average looking faces again revealed an accessibility benefit for attractive female faces, suggesting that greater accessibility was not a function of mentally sorting the lists and retrieving the attractive females first. In fact, when the memory set included 4 faces, a significant advantage for attractive vs. average retrievals suggests that capacity limits are less of a constraint for functionally relevant faces. A third study used black and white male faces with angry and happy expressions, and generalized the functional accessibility effect to angry black males. Taken together, these findings suggest that short–term encoding processes evolved to automatically privilege information of high functional relevance.
The Measure of IQ Among People with Little to No Education: An Assessment of the Validity of Raven's Colored Progressive Matrices
The Raven's Colored Progressive Matrices (RCPM) test is often assumed to be a culturally–neutral instrument for assessing fluid intelligence, or 'g.' Other evidence indicates that schooling has a significant effect on test performance. Here I present data collected among the Tsimane, a forager–horticultural society in central Bolivia. The Tsimane are notable for variable levels of education and degrees of exposure to a market economy, which allows for fine–grained analyses of factors influencing psychometric test performance. Subjects (N=185, ages 8–18) from four communities were administered RCPM and demographic information related to health, residential patterns, parental education and wealth were collected. Results indicate that exposure to schooling and, in particular, child literacy is significantly correlated with performance on RCPM (p=.0001). In turn, parents' ability to speak Spanish was the strongest predictor of their child's ability to read. (p=0.035). These findings indicate that psychometric test performance co–varies significantly with schooling exposure and parental attributes–important considerations for Tsimane youth as they shift to a market–oriented society.
Deadly Sin or Functional Adaptation? An Evolutionary View of Envy
Envy is the emotional experience that occurs when your possessions, qualities or achievements are inferior to those of another, and you desire to achieve what the other has. The emotional experience of envy may have evolved as a mechanism for choosing an effective behavioral response to the adaptive problem of being inferior to conspecific competitors in some fitness relevant domain. The present study was designed to determine whether different types of envy situations evoke specific emotions which are related to specific behavioral responses. People's emotional responses to envy situations are specific to the type of resource being envied as well as to the method by which their competitor acquired that resource. A follow up study will investigate the relationship between these emotional responses and the behaviors they invoke.
Suppression of Estrus Through Hormonal Contraception Disrupts Effects of Partner Symmetry on Women's Orgasm Frequency
Past research suggests that female orgasm may respond selectively to cues of male quality, and may function, in part, to enhance the effectiveness of short–term mating to enhance the genetic quality of offspring. Adaptations for good-genes mate choice are frequently estrus-limited in their expression, producing shifts in preferences and behaviors across the menstrual cycle. Because these shifts are, in all likelihood, mediated by reliable hormonal changes during estrus, predictions of estrus–limited function can also be tested indirectly, through the effects of artificial manipulation of hormone levels by contraceptive drugs. In a reanalysis of data on male fluctuating asymmetry and frequency of female orgasm in 203 heterosexual couples, an association between male partner fluctuating asymmetry and female orgasm frequency, and particularly the frequency of coital orgasm during or after male ejaculation, was present and strong in normally cycling women but absent in women taking hormonal contraceptives. The effects were independent of relationship quality and demographic variables, and contraceptive groups did not differ in age, ethnicity, or mean orgasm frequencies. This finding is consistent with a genetic–benefits account of female orgasm function, most notably the cryptic sperm choice hypothesis. Because hormonal contraceptives suppress estrus, similar effects of contraceptive use can be expected for other cyclically expressed, hormonally mediated adaptations for mating; this method of testing mate choice hypotheses can be useful, even if preliminary, when data directly assessing cyclical shifts are unavailable. Future research might profitably explore whether patterns of female orgasm are indeed estrus–dependent.
Love, Lust, and Loyalty: Sex Differences in Responses to and Reasons for Infidelity Among 65,029 Online Participants
Evolutionary psychologists have proposed that men are more upset than women by sexual infidelity and women are more upset than men by emotional fidelity. Most studies, however, have relied on small college student or community samples. Further, few studies have examined moderators or the extent to which emotional vs. sexual motives actually contribute to infidelity. We investigated these issues among 65,029 online participants. Heterosexual men were more likely than heterosexual women to be upset by sexual infidelity (53% vs. 35%) and less likely to be upset my emotional infidelity (47% vs. 65%). Among heterosexuals, gender was the strongest predictor of upset by sexual infidelity compared to 18 other demographic and attitudinal factors. Only two factors erased the gender difference: sexual orientation and participation in "open" relationships. Compared to unfaithful women, unfaithful men were more likely to be motivated to cheat by desires for sexual variety and less by desires for emotional intimacy.
Is Extreme Thinness an Especially Strong Signal of Infectious Disease?
Previous person perception research suggests that certain types of deviations from species–typical morphological norms may heuristically signal infectious disease (Schaller & Duncan, 2007). Extremely obese individuals, for instance, are implicitly associated with disease–connoting cognitions (Park, Schaller & Crandall, 2007). The present studies tested whether extreme thinness also functions as such a cue. Using a computer–based reaction–time methodology, an initial study (N=56) revealed that extremely thin people (compared to normal–weight people) are implicitly associated with semantic concepts connoting unpleasantness in general and disease in particular (p's < .000). A second study (N =52) tested the automaticity and the relative strength of both obesity and extreme thinness as disease cues. Participants were given explicit information about the disease–status of two target individuals: one appeared normal but was described as suffering from an infectious disease, while the other was of grossly deviant weight (either obese or extremely thin, depending on experimental condition) but was explicitly described as healthy. A reaction time task then assessed which target individual (the truly diseased person or the obese/thin person) was more strongly associated with disease. Results revealed an implicit association of extreme thinness with disease, indicating that thinness trumped rational knowledge as a disease–connoting cue (p = .001). No such effect was observed in the obesity condition. These results reveal that extreme thinness is a heuristic cue signaling disease. Furthermore, they suggest that, perhaps because extreme thinness is an especially honest signal of disease, it is also an especially strong one.
Jealousy, Friendship and the Banker's Paradox
According to the Banker's paradox model, friendships are deep–engagement relationships that were critical for navigating and surviving in our ancestral past. The threat of another person encroaching on this relationship signifies the potential for investment received from a friend to be diverted elsewhere, leading to feelings of being replaced. Participants were asked to write about a time when they were jealous of a relationship their same–sex best friend had with another same same–sex person as well as when their best friend had a romantic partner. Participants reported feeling replaced by the third party significantly more when the interloper was of the same–sex as the participant than when the interloper was their friend's romantic partner. Conversely, participants reported feeling that their friend spent less time (loss of time) with them when the interloper was a romantic partner than when the interloper was a same–sex individual. In addition, the relationship between loss of time and jealousy was fully mediated by feeling replaced by the interloper. This was the case for both same sex interloper and when the interloper was the best friend's romantic partner (although to a lesser degree). These data suggest that in deep engagement relationships, events that indicate one is being replaced are the specific trigger for the emotional response of jealousy.