Abstract
We have the ability to extract mean emotion from multiple faces. However, the boundaries of multiple facial expression processing are largely unknown. In this study, we tested the processing capacity of mean emotion representation by using the simultaneous-sequential paradigm. In Experiment 1, each set consisted of 16 faces conveying a variable amount of happy and angry expressions and was presented for 500ms. Participants were asked to judge on a continuous scale the perceived average emotion intensity from each set. In the simultaneous condition, the 16 faces were presented concurrently; in the sequential condition, two sets containing each 8 faces were presented successively. We found that average emotion judgments varied parametrically with changes in the happy vs. angry faces ratio. In addition, performance in the sequential was better than in the simultaneous condition, revealing a limited-capacity processing. Experiment 2 was the same as Experiment 1, except that different stimulus displays were used. Either happy and neutral, or angry and neutral expressions made up the face sets. The results confirmed that the average emotion judgments were sensitive to the emotional content of the face sets. However, the averaging process turned out to be qualitatively different between these two opposite emotions. Whereas it was clearly capacity-limited for happy faces (as found in Experiment 1), there was no significant difference between the sequential and simultaneous conditions for angry faces, suggesting unlimited capacities. Interestingly, post-experiment ratings showed that neutral faces were perceived as slightly negative. Altogether, these findings suggest that averaging multiple facial expressions is best conceived as a capacity-limited perceptual process. However, an asymmetry between positive and negative facial expressions can be observed, with the latter emotion facilitating the rapid averaging process, presumably given its enhanced motivational significance for the organism and/or the reduced inter-stimulus variability along the valence dimension.
Meeting abstract presented at VSS 2017