Facial movement varies by sex and is related to attractiveness Edward R. Morrison a, 4 , Lisa Gralewski b , Neill Campbell b , Ian S. Penton-Voak a a Department of Experimental Psychology, University of Bristol, Bristol BS8 1TU, UK b Department of Computer Science, University of Bristol, Bristol BS8 1TU, UK Initial receipt 9 October 2006; final revision received 5 January 2007 Abstract Facial movement has received little attention in studies of human attractiveness, yet dynamic displays are an important aspect of courtship in many species. This experiment investigated whether facial movement could be used to identify sex, and whether the ease of identification was associated with attractiveness. We removed shape cues to sex by applying movement from individual faces to a standardised facial model. Participants were able to distinguish between male and female animations of this model at levels above chance. Furthermore, there was a positive association between ease of sex identification and attractiveness for female, but not male, faces. Analysis of facial movement suggested several behaviours that are more frequent in women than men (blinking, tilting, nodding, shaking, and amount of movement). Although some of these behaviours may be cues to sex identification, none alone was directly linked to attractiveness. Our findings suggest that feminine motion is attractive in female faces, but sexually recognisable movement has no clear influence on male attractiveness, in agreement with work on static faces employing composite images. D 2007 Elsevier Inc. All rights reserved. Keywords: Facial attractiveness; Dynamic stimuli; Sex differences; Mate choice 1. Introduction Biological approaches to mate choice hold that cues such as symmetry (Møller & Thornhill, 1998) and sexual dimorphism are attractive (Andersson, 1994). In humans, studies of facial attractiveness have argued that averageness and symmetry may signal developmental stability and resistance to disease (Thornhill & Møller, 1997) and heterozygosity (Gangestand & Buss, 1993) and, hence, be considered attractive. Sexual dimorphism is attractive in female faces, perhaps because it signals youth and fertility, which are valuable traits in a potential mate (Perrett et al., 1998). These structural cues may signal useful information to prospective mates (Fink & Penton-Voak, 2002). Sexually dimorphic characteristics in male faces are not unequivo- cally attractive but can be in circumstances when putative heritable bqualityQ is paramount in importance, such as in short-term as opposed to long-term attractiveness (Little, Jones, Penton-Voak, Burt, & Perrett, 2002). Two recent reviews summarise this literature admirably (Gangestad & Scheyd, 2005; Rhodes 2006). Despite the wealth of studies in the area of facial attractiveness, the general reliance on static stimuli in the research to date is a concern. Rubenstein (2005) reported a low correlation between the attractiveness of individual faces presented in static and dynamic conditions (r =.19 and r = .21, p N .18), a finding that suggests that conclusions from experiments with static faces should be treated with caution. A static face is, in many ways, a poor stimulus, since faces are always dynamic in real social interactions. Facial motion is known to convey cues about identity (Bassili, 1978; Bruce & Valentine, 1988; Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999; Pike, Kemp, Towell, & Phillips, 1997; Thornton & Kourtzi, 2002) and emotional expression (Bassili, 1978, 1979). Rubenstein (2005) showed that emotion is an important cue to attractiveness in dynamic faces, suggesting that static images may lack important social cues relevant to attrac- tiveness. Indeed, Riggio, Widaman, Tucker, and Salinas (1991) used ratings of behaviour from video sequences to argue that dynamic information was an important component of overall attractiveness independent of facial (static) beauty from photographs, although the study could not specify what aspects of movement were important in these judgements. 1090-5138/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.evolhumbehav.2007.01.001 4 Corresponding author. Tel.: +44 0117 954 6621. E-mail address: ed.morrison@bris.ac.uk (E.R. Morrison). Evolution and Human Behavior 28 (2007) 186 – 192