About this Research Topic
Aftereffects are the psychophysists microelectrode (Frisby, 1979) and can allow for an exploration of the neural representation of particular stimuli (Li, Tzen, Yadgarova, & Zaidi, 2008) including faces. Two distinct forms of aftereffect have been identified in face perception: the face-distortion aftereffect (FDAE) and the face-identity aftereffect (FIAE). In both cases, prolonged exposure to the adaptor face causes a test face to take on the “opposite” characteristics (e.g., a normal face will appear compressed following adaptation to an expanded face, Webster & MacLin, 1999).
Leopold, O’Toole, Vetter, & Blanz (2001) demonstrated that identification of a particular face was facilitated by adaptation to an anti-face (opposite in terms of Euclidean geometry). Theoretically, it has been proposed that adaptation shifts the perceived face norm toward the adaptor face (Anderson & Wilson, 2005), making the opposite face easier to identify (Rhodes, Robbins, Jaquet, McKone, Jeffery, & Clifford, 2005). Aftereffects do not readily transfer across faces of different gender (Little, DeBruine, Jones, & Waitt, 2008), race (Jaquet, Rhodes, & Hayward, 2007), or orientation (Rhodes, Jeffery, Watson, Jaquet, Winkler, & Clifford, 2004), indicating populations of neurons representing certain classes of faces (Rhodes, et al., 2004). Aftereffects do, however, transfer across viewpoints (Jiang, Blanz, & O’Toole, 2006) and image size (Zhao & Chubb, 2001), but to a significantly lesser degree than within-view and within-size adaptation for unfamiliar faces. The transfer across viewpoints is more robust for familiar faces (Hole, 2010) and there is cross-modality transference for familiar faces (e.g., adaptation to voices caused aftereffects in faces, Hills, Elward, & Lewis, 2010). Evidently, adaptation effects are greater when there is greater perceptual similarity between the adaptor and the test stimulus.
Face aftereffects have also been shown to depend on exposure and test timings. The magnitude of the FIAE is greater when the duration of the adaptor is long and the duration of the test stimulus is short (Rhodes, Jeffery, Clifford, & Leopold, 2007). For unfamiliar faces, the FIAE is short-lived, lasting about five seconds. However, for familiar faces, aftereffects are long-lasting, lasting about 80 minutes (Carbon & Leder, 2005) or more (Hills & Lewis, in preparation). For long-term effects, participants received visual input, including faces, between adaptation and the test. Nevertheless, these aftereffects persisted, suggesting some sort of learning or neural change had occurred. Indeed, this highlights important and underexplored aspects of face aftereffects: the effect of familiarity and the neural and brain correlates of adaptation and aftereffects, although Jacques, d’Arripe, & Rossion (2007) have demonstrated that repeated presentations of a face reduced the magnitude of the ERP N170 (see also, Caharel, d’Arripe, Ramon, Jacques, & Rossion, 2008).
This Research Topic, thus, has a broad scope for exploring the FIAE using behavioural, electrophysiological, neuroimaging, and eye-tracking research. It is expected that all papers address how faces are represented in the brain and what aftereffects tell us about this representation. Articles are encouraged that particularly explore the differences in aftereffects between familiar and unfamiliar faces. Research reports, reviews, theoretical expositions, and methodological papers are welcome.
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