522Many studies have used visual adaptation to investigate whether recent visual experience influences face perception (e.g., Calder, Jenkins, Cassel, & Clifford, 2008;DeBruine, Jones, Unger, Little, & Feinberg, 2007;Little, DeBruine, & Jones, 2005;Rhodes, Jeffery, Watson, Clifford, & Nakayama, 2003;Webster, Kaping, Mizokami, & Duhamel, 2004;Webster & MacLin, 1999). For example, adaptation to faces with expanded feature spacing causes the feature spacing of unmanipulated faces to appear contracted, whereas adaptation to faces with contracted feature spacing causes the feature spacing of unmanipulated faces to appear expanded (Webster & MacLin, 1999). Other studies have shown that adaptation to faces with either expanded or contracted feature spacing causes the adapted feature spacing to appear more normal and more attractive (Rhodes et al., 2003). This effect of adaptation on attractiveness judgments is thought to reflect the correlation between perceived normality and attractiveness (DeBruine et al., 2007;Rhodes et al., 2003).The effects of visual adaptation on face perception occur when the same individuals (see, e.g., Yamashita, Hardy, De Valois, & Webster, 2005) and when different individuals (see, e.g., Rhodes et al., 2003;Yamashita et al., 2005) are shown at adaptation and test. Furthermore, aftereffects for normality and attractiveness judgments of faces occur when the faces shown during the adaptation and test phases differ in size (e.g., Bestelmeyer et al., 2008;Little et al., 2005) or in orientation (e.g., Jeffery, Rhodes, & Busey, 2006;Rhodes et al., 2003), suggesting that face aftereffects reflect adaptation of neurons that code high-level aspects of faces, rather than low-level (e.g.
University of Stirling, Stirling, ScotlandWe investigated the effects of adaptation to mouth shapes associated with different spoken sounds (sustained / / or / /) on visual perception of lip speech. Participants were significantly more likely to label ambiguous faces on an / /-to-/ / continuum as saying / / following adaptation to / / mouth shapes than they were in a preadaptation test. By contrast, participants were significantly less likely to label the ambiguous faces as saying / / following adaptation to / / mouth shapes than they were in a preadaptation test. The magnitude of these aftereffects was equivalent when the same individual was shown in the adaptation and test phases of the experiment and when different individuals were presented in the adaptation and test phases. These findings present novel evidence that adaptation to natural variations in facial appearance influences face perception, and they extend previous research on face aftereffects to visual perception of lip speech.