Differences in eye movements between same and other race face recognition

Differences in eye movements between same and other race face recognition. Eve K. Klama (eklama.enq@googlemail.com) Department of Psychology, University of Exeter United Kingdom Fraser Milton (f.n.milton@exeter.ac.uk) Department of Psychology, University of Exeter United Kingdom Abstract Eye movements of twelve Caucasian participants were measured whilst they performed a recognition test of same (Caucasian) and other race (Indian) faces. We observed a standard other-race effect, with more items recognised correctly, fewer false alarms, and reduced reaction time to same-race than other-race faces. Additionally, a differential pattern of eye movements between races emerged. During the study phase, same- race faces were fixated more than other-race faces, whilst other-race faces resulted in a greater proportion of fixations to internal face features than same-race faces. At test, whilst no differences between races emerged in the number of fixations or in the proportion of fixations made to internal features, a significantly greater level of fixations were made to the left hemispace for other-race faces for both previously studied and lure faces. These differences in the pattern of fixation plausibly reflect the greater effort in the processing of other-race than same-race faces. Keywords: other-race effect, eye-tracking, face recognition, same-race faces. Introduction The other-race effect refers to the phenomenon that individuals are less proficient at recognising faces from a different race to their own. This is typically characterised by a ‘mirror effect’, whereby same-race faces attract a higher proportion of hits and a lower proportion of false alarms compared with other-race faces (Meissner & Brigham, 2001). As well as its theoretical importance, the other-race effect has considerable practical significance. In particular, it is well established that minority races in a community are more likely to be wrongfully convicted of a crime on the basis of erroneous eyewitness testimony (Meissner & Brigham, 2001). For instance, Scheck, Neufeld, & Dwyer (2000) found that most cases of mistaken eyewitness identification in the United States were of Caucasian victims misidentifying non-Caucasian suspects. One explanation for the other-race effect is that individuals process other-race faces in a qualitatively different way to same-race faces. In particular, same-race faces are believed to rely on configural processes to a greater extent than other-race faces. Support for this comes from the composite face effect (e.g., Michel, Rossion, Han, Chung, & Caldara, 2006) in which recognition of the upper half of a face was more disrupted by the bottom half of a different face for same-race than other-race faces. Furthermore, there is greater benefit for same-race than other-race faces from the whole face context when processing individual facial features (the whole/part effect, e.g., Tanaka, Kiefer, & Bukarch, 2004). Additionally, there is evidence that the face inversion effect is more pronounced for same-race than other-race faces (Rhodes et al., 1989; but see Valentine & Bruce, 1986). The greater exposure that people typically have to same-race faces (e.g., Chiroro & Valentine, 1995) may be one reason for the increased use of configural processes (Gauthier & Tarr, 2002). Similarly, perceptual learning (e.g., Gibson & Walk, 1956; McLaren & Mackintosh, 2000) may lead to same-race faces being less tightly clustered in multidimensional space than other-race faces, resulting in easier discrimination of same-race faces (as in “face-space” models, e.g., Byatt & Rhodes, 2004). Eye movements provide an index to the allocation of visual attention towards facial features (Findlay & Gilchrist, 2003). As such, the pattern of eye movements can provide direct insight into cross-race processing differences. To date, however, eye tracking has seldom been used to explore the other-race effect. One exception is a study by Goldinger, He, & Papesh (2009) which examined eye movements to various features together with pupil dilation (an index of mental processing load in visual attention) for Caucasian and Asian faces, recruiting participants from both these races. Both Caucasian and Asian participants fixated more to same-race than other-race faces, and more to the eyes and hair for same-race faces and more to the nose and mouth for other-race faces. Pupil dilation was greatest for other-race faces, indicating the recruitment of greater resources. A separate study conducted by Blais, Jack, Scheepers, Fiset, & Caldara (2008) found a slightly different pattern of results, with Caucasians focussing on the eyes and East Asians focusing on the nose and mouth, regardless of the race of the faces viewed. As Goldinger et al. (2009) note, this discrepancy may be partially due to the fact that in their study they used faces with neutral emotions, whilst the faces presented in Blais et al. (2008) varied in expression. Our study directly examined differences in the processing of internal features, relative to external features, for same- race compared to other-race faces. We also asked whether there would be cross-race differences in fixation