Effects of temporal properties of facial expressions on the perceived intensity of emotion

Abstract

A series of multiple facial expressions can be temporally perceived as an averaged facial expression in a process known as ensemble perception. This study examined the effect of temporal parameters on the perceived intensity of facial expression in each emotion, and how the effect varies with autistic traits in typically developing people. In the experiment, we presented facial expressions that switched from emotional to neutral expressions, and vice versa, for 3 s. Participants rated the overall perceived intensity of the facial emotions as a whole rather than rating individual items within the set. For the two tasks, a ratio of duration of emotional faces to duration of neutral faces (emotional ratio) and the timing for transitions were manipulated individually. The results showed that the intensity of facial emotion was perceived more strongly when the presentation ratio increased and when the emotional expression was presented last. The effects were different among the emotions (e.g. relatively weak in the anger expression). Moreover, the perceived intensity of angry expressions decreased with autistic traits. These results suggest that the properties and individual differences in the facial ensemble of each emotion affect emotional perceptions.

Temporal characteristics of facial ensemble in individuals with autism spectrum disorder: examination from arousal and attentional allocation

“…If the three trials failed, we conducted the ensemble task without eye tracking (six participants in the ASD group and three in the TD group). The number of participants without eye tracking was comparable to that of a previous study ( 24 ). Failures were most likely caused by equipping glasses to correct astigmatism.…”

“…The apparatus and stimuli were the same as those described in Harada et al. ( 24 ). An LED monitor and desktop PC were used to conduct the study.…”

“…To investigate this issue, Harada et al. ( 24 ) examined whether autistic traits, measured using the Autism-Spectrum Quotient (AQ: 25 , 26 ), influenced temporal facial ensembles. In this study, the participants viewed facial expressions serially switched between emotional and neutral.…”

“…They found that facial ensembles were influenced by the ratio of emotional expression time to total presentation time. Participants with higher autistic traits tended to score the perceived intensity of angry expressions as low ( 24 ). However, a higher AQ score does not always indicate a clinical diagnosis of ASD ( 27 ).…”

“…The experimental procedure was as described by Harada et al. ( 24 ). In this experiment, facial expressions were presented serially for three seconds and pseudo-randomly switched between emotional and neutral stimuli.…”