Abstract
The current study evaluated the theory that attention boosts perceived contrast (Carrasco, Ling, & Read, 2004) by employing a novel measure of contrast: gender perception of ambiguous faces. Given that the apparent gender of a face has been shown to be related to contrast (Russell, 2009), we sought to use gender perception as a measure of whether perceived contrast indeed increases with attention. Participants performed a gender judgment task wherein the locus of attention was independently manipulated prior to stimulus presentation. On each trial, after 800 ms of fixation, an exogenous peripheral or neutral cue appeared for 50 ms, followed by a 50 ms presentation of the lower-region of two ambiguous faces. Participants reported which of the two faces appeared to be more female (Experiment 1) or more male (Experiment 2). Results showed that as the brightness contrast of a face increased, participants were less likely to report the face as female (Experiment 1) or more likely to report it as male (Experiment 2). While this contrasts with the demonstration by Russell (2009), a key difference is that we manipulated image contrast, whereas Russell specifically manipulated the contrast of the lips and eyes to the remaining face. Critically, the effect of attention did not consistently follow the effect of physical contrast on face perception, meaning that attention did not increase perceived contrast. Instead, attention increased the tendency to report a face as being more female (Experiment 1) or more male (Experiment 2). Our results support the hypothesis that attention does not boost perceived contrast, but instead causes an increase in the tendency to report stimuli in the attended region as being more salient (Schneider & Komlos, 2008).
Natural Sciences and Engineering Research Council of Canada.