Adaptation to different mouth shapes influences visual perception of ambiguous lip speech

Abstract

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.

Adaptation to Antifaces and the Perception of Correct Famous Identity in an Average Face

“…Experiment 2 then demonstrates equivalency in results based on web-based and laboratory-based adaptation studies of this kind. We note that while individuals may intuitively feel that data collected in the absence of an experimenter may produce more variable results, there is growing evidence that adaptation effects seen under laboratory conditions are also seen in web-based studies (Jones et al, 2008, 2010). Our experiment here demonstrates that the same effect is seen in experiments 1 and 2 despite difference in recruitment, presence of experimenter, and variation in equipment.…”

Face Distortion Aftereffects Evoked by Featureless First-Order Stimulus Configurations

“…For example, an undistorted face seems expanded after viewing a face with features compressed toward the midline. Besides distortion, FAEs have been observed for a number of natural facial properties including identity (Leopold et al, 2001), gender (Webster et al, 2004), age (Schweinberger et al, 2010), ethnicity (Webster et al, 2004) as well as more dynamic facial features such as emotional expression (Webster et al, 2004; Fox and Barton, 2007), eye-gaze direction (Jenkins et al, 2006; Seyama and Nagayama, 2006), and lip angle (Jones et al, 2010). …”

Selectivity of Face Distortion Aftereffects for Differences in Expression or Gender

“…Consistent with this, other studies have found analogous asymmetric effects of expression or identity changes on face recognition and discrimination tasks (Schweinberger and Soukup, 1998; Schweinberger et al, 1999; Atkinson et al, 2005). (Conversely, there are also examples where changeable aspects of the face such as mouth shape can show aftereffects that show little dependence on identity (Jones et al, 2010). …”