The impact of visible dental decay on social judgements: comparison of the effects of location and extent of lesion.
Previous research has established that people can make social judgements about someone else based on the condition of that person's teeth. The characteristics of visible tooth decay, with respect to the effect on such social judgements, have not, however, been subject to extensive investigation. This study sought to determine whether the position of visible decay and/or the extent of the lesion are determining factors in such social judgements of each other. In a between subjects design, 100 young people were randomly divided into 4 groups of 25 and each group shown a differently computer-modified photograph of the same person. Extent and location of the lesion were varied systematically. Participants were asked to rate the person in the photograph with respect to intellectual ability, social competence and psychological adjustment. The scores from those questions were analysed with one way analysis of variance (ANOVA) then Tukey's HSD where ANOVA revealed significant differences. The data confirmed previous studies that have shown that poor dental condition is highly correlated with perceived poor social performance and intellectual ability. Further, the data showed that with respect to the constructs of intellectual ability, extraversion and care for one's personal appearance, a more central position of caries is more predictive of poor social judgements than just the presence of visible decay, or even twice the amount of decay. We discuss the possible evolutionary and ontological reasons for making social judgements that are influenced by a person's dental health as well as considering the implications of our findings for dentists.