On “knowing your partner”: Dangerous illusions in the age of AIDS?


  • We are grateful to Bella DePaulo, Bev Fehr, Jeff Fisher, Daniel Gilbert, Mike Gill, and Stephen Misovich for their comments on an earlier version of this article. We also thank Jeff Fisher for allowing us to use the videotape “People like Us” to produce the stimulus materials for Study 2, as well as the many people who helped us in the data reduction and experimental phases of this research. This research was supported by Graduate Research Doctoral Fellowship GER-9253937 from the National Science Foundation to the second author.

regarding this article should be sent to William B. Swann, Jr., Department of Psychology, University of Texas, Austin, Texas, 78712. E-mail: SWANN@.PSY.UTEXAS.EDU.


We identified two characteristics of the impression formation process that may cause people to underestimate the riskiness of potential sexual partners. In Study 1, participants were quite confident that they could determine whether someone was lying to them about risk-related behavior when, in reality, they could not. Particularly troubling was a “truth bias” that resulted in relatively high rates of truth detection, but poor lie detection. In Study 2, increased familiarity with a target person (who actually was HIV+) caused participants to lower their estimates of the target's riskiness, despite the fact that we explicitly warned them that the target might be HIV+. We suggest that such processes may foster the illusion of knowing one's partner when one does not.