تقارن صورت و پنج عامل بزرگ شخصیتی

The present study investigated possible associations between facial symmetry and actual personality as assessed by the ‘big-five’ personality factors: neuroticism (N), extraversion (E), openness (O), agreeableness (A), and conscientiousness (C). Digital photographs were taken of male and female faces, volunteers also completed the NEO-FFI personality inventory. Facial images were analysed for horizontal symmetry by means of digital image processing. Following previous reports we predicted that facial symmetry should be negatively related to neuroticism but positively related to extraversion, openness, agreeableness, and conscientiousness. In general, our data on actual personality confirmed previous reports on perceptions of personality for neuroticism and extraversion. Neuroticism was found to be negatively but not significantly related to facial symmetry whereas extraversion was positively associated. In contrast to previous data, we found significant negative associations between facial symmetry and openness and agreeableness. Conscientiousness was non-significantly related to facial symmetry. The strongest associations with facial symmetry were found for extraversion and openness. Our results suggest that behavioural perceptions of an individual may reflect an individual’s actual personality, and facial symmetry is a correlate of personality. However, because of some inconsistencies between this and previous studies we suggest that (1) the associations between facial symmetry and personality traits require further investigation, and (2) future studies should urge for methodological consistency to make results comparable.

Evolutionary psychologists claim that facial symmetry pertains to health, suggesting that humans have evolved to view certain features as attractive because they were displayed by healthy individuals. The hypothesis that attractiveness assessments are sensitive to facial symmetry has been tested in a number of studies (e.g. Grammer & Thornhill, 1994; see reviews by Thornhill & Gangestad, 1999 and Grammer, Fink, Møller, & Thornhill, 2003) and it has been taken for granted that preferences for symmetrical faces may thus have some adaptive value. However, despite several studies demonstrating the direct effects of symmetry on rated attractiveness, other research suggests that symmetry can be associated with attractiveness for other reasons. For example, Scheib, Gangestad, and Thornhill (1999) found a relationship between women’s attractiveness ratings of faces and symmetry even when symmetry cues were removed by presenting only the left or right half of each face. This suggests that attractive features other than symmetry may be used to assess physical condition. Symmetry may thus simply covary with these other features rather than act as a primary cue to attractiveness. Moreover, Johnstone (1994) has argued that symmetry preferences may reflect a by-product of selection for mate recognition, which is likely to arise in the absence of any link between symmetry and quality. Despite studies that suggest the existence of sensory biases for symmetry, it seems more commonly accepted that preferences for symmetry have evolved because the degree of symmetry in signals indicates the signaler’s quality (Enquist & Arak, 1994). Shackelford and Larsen (1997) assessed the relationships between facial asymmetry, various measures of personality, and daily diary reports of behaviour and observer ratings of personality/attractiveness in two samples of undergraduate students. Despite some differences between samples, the authors reported correlations between facial symmetry and perceived personality factors in that asymmetrical faces were rated as being more neurotic, less agreeable, and less conscientious. Interestingly, they found clear comparisons between self-ratings of personality, and observer ratings of the same individual from photographs. More recently, Noor and Evans (2003) tested whether facial symmetry had a causal effect on the perception of personality (specifically the dimensions of the five-factor model) by using faces that varied in their degree of asymmetry. In their study, digital photographs of female targets were manipulated into two symmetrical (left-left and right-right) images, one asymmetrical version, and the unaltered original. Participants rated these four versions on the five personality domains. The asymmetrical versions were rated as being more neurotic, less agreeable, and less conscientious; however no significant relationships were found for facial symmetry, openness, and extraversion. Like the previously cited reports, this current study aimed to discover possible associations between facial symmetry and personality domains by directly assessing personality characteristics in individuals in whom the degree of asymmetry in their faces was actually determined. Although there is no consensus on a single personality model, it appears that researchers have reached some agreement on the number and nature of personality dimensions (see for example Budaev, 1999). It has been proposed that human personality variation may be summarised by five major dimensions (McCrae & Costa, 1997). These are known as the ‘big-five’ factors: ‘extraversion (E)’, ‘openness (O)’, ‘agreeableness (A)’, ‘neuroticism’ (N), and ‘conscientiousness (C)’ (Digman, 1990 and Wiggins, 1996), which are held to be a complete description of personality (McCrae & Costa, 1997). In light of previous research (Noor and Evans, 2003 and Shackelford and Larsen, 1997) we predicted that facial symmetry should be negatively related to neuroticism but positively related to extraversion, openness, agreeableness, and conscientiousness. If the association between facial symmetry and actual personality dimensions follows the same pattern as it is reported for perceived personality, this would substantiate the notion that facial symmetry may signal (in addition to physical qualities) other behavioural variables relevant in social encounters.