INTRODUCTION

1. Evolved Disease-Avoidance Processes and Implicit Antipathy Toward the ElderlyLesley A. Duncan and Mark SchallerUniversity of British Columbia INTRODUCTION Anomalous facial features can automatically elicit aversive reactions from perceivers. These reactions may be the result, in part, of evolved disease avoidance mechanisms that (a) are sensitive to cues (such as deviations from morphological prototypes) indicating the possible presence of parasites in other people, and (b) automatically activate aversive cognitions when such cues are perceived. In addition, an evolutionary cost/benefit analysis implies that these mechanisms are likely to be functionally flexible: They are especially likely to be triggered when perceivers feel especially vulnerable to infection themselves (Schaller & Duncan, 2007). The present research investigates whether visible signs of aging (e.g. wrinkles) activate these disease-avoidance mechanisms, thus contributing to implicit negative responses to elderly people. We assessed implicit cognitive associations linking elderly people to semantic concepts connoting disease and other unpleasant things. And we tested the extent to which these implicit negative associations are affected by chronic concerns about germ transmission, and by the temporary salience of germs. METHODS Individual Difference Measures: 55 university students completed two questionnaire measures relevant to chronic concerns with germ transmission and contagion: Perceived Vulnerability to Disease and Disgust Sensitivity. Manipulation of Temporary Germ Salience: Participants viewed one of two brief slide show presentations. One slide show depicted the threat posed by germs and infectious diseases. The other depicted disease-irrelevant threats to well-being (e.g., electrocution, and other kinds of accidents). Implicit Association Tasks (IATs): Participants performed two different computer-based reaction-time tasks. One IAT assessed the extent to which old people (in comparison to young people) were implicitly associated with the semantic concept "unpleasant." The other IAT assessed the extent to which old people (vs. young people) were implicitly associated with the more specific semantic concept "disease." Participants were presented serially with target words that were either pleasant or unpleasant (or that either connoted disease or health) and with photographs of either young faces or old faces (Levy & Banaji, 2002). Participants responded to each stimulus word by categorizing it as either "pleasant" or "unpleasant" (or as connoting either "disease" or "health"), and they responded to each photograph as depicting either "young" or "old". On one critical block of trials (Figure 1), the category "old" shared a response key with the category "unpleasant" (or "disease"); on another critical block of trials, "young" shared a response key with "unpleasant" (or "disease“). Overall IAT indices were computed (in the manner prescribed by Greenwald et al., 2003) that compared response times on the two critical blocks of trials. More highly positive values on these IAT indices indicate the activation of implicit cognitive associations in which old people (compared to young people) are more strongly linked with the concepts "unpleasant" and "disease." RESULTS Regression analyses tested the extent to which the individual difference measures and the germ-salience manipulation influenced implicit cognitive associations. No meaningful effects emerged on the IAT task that focused specifically on "disease," but several effects emerged on implicit associations linking old people to more generally "unpleasant" concepts. This implicit antipathy toward old people was stronger among individuals who scored more highly on Perceived Vulnerability to Disease (beta = .31, p = .021), and was also stronger among people with a greater Disgust Sensitivity (beta = .26, p =.051). There also was a trend (p = .098) toward an interaction between Disgust Sensitivity and the experimental manipulation of germ salience. This interaction is depicted in Figure 2. DISCUSSION These results provide preliminary evidence that evolved disease-avoidance processes may contribute to ageist attitudes. Implicit antipathy toward old people was stronger among people who are chronically more worried about contagion. Plus (although the interaction was not quite statistically significant) the results suggested that even people who aren't chronically worried about contagion may also sometimes show greater antipathy toward old people – if the threat of disease is made temporarily salient. It is interesting that that these effects emerged only on the implicit measure of general antipathy, but not the measure that focused specifically on disease-connoting cognition. Why would this be? One possibility is that the observed effects may not implicate a disease-avoidance mechanism after all. But if so, it's not clear why feelings of vulnerability to disease specifically produced the results that were observed. Another possibility is this: A more generally aversive set of cognitions may often be activated by disease-connoting cues because negative cognitions in general (even those that seem irrelevant to the immediate functional context) may still compel the adaptive behavioral response: Avoidance. Figure 1. A Trial in the Old-Unpleasant IAT Task OLD or UNPLEASANT YOUNG or PLEASANT Note: In this trial, “Old” and “Unpleasant” shared the same response key. Figure 2. Interaction between Disgust Sensitivity and Temporary Germ Salience REFERENCES Greenwald, A. G., Nosek, B. A., & Banaji, M. (2003). Understanding and using the implicit association test: I. An improved scoring algorithm. Journal of Personality and Social Psychology, 85, 197–216. Levy, B., & Banaji, M. R. (2002). Implicit ageism. In T. Nelson (Ed.), Ageism: Stereotyping and prejudice against older persons (pp. 49-75). Cambridge: MIT Press. Schaller, M., & Duncan, L. A. (2007).  The behavioral immune system: Its evolution and social psychological implications.  In J. P. Forgas, M. G. Haselton, & W. von Hippel (Eds.), Evolution and the social mind: Evolutionary psychology and social cognition (pp. 293-307).  New York: Psychology Press.