Emotional judgments of scenes are influenced by unintentional averaging

Abstract

Background: The visual system uses ensemble perception to summarize visual input across a variety of domains. This heuristic operates at multiple levels of vision, compressing information as basic as oriented lines or as complex as emotional faces. Given its pervasiveness, the ensemble unsurprisingly can influence how an individual item is perceived, and vice versa.

Methods: In the current experiments, we tested whether the perceived emotional valence of a single scene could be influenced by surrounding, simultaneously presented scenes. Observers first rated the emotional valence of a series of individual scenes. They then saw ensembles of the original images, presented in sets of four, and were cued to rate, for a second time, one of four.

Results: Results confirmed that the perceived emotional valence of the cued image was pulled toward the mean emotion of the surrounding ensemble on the majority of trials, even though the ensemble was task-irrelevant. Control experiments and analyses confirmed that the pull was driven by high-level, ensemble information.

Conclusion: We conclude that high-level ensemble information can influence how we perceive individual items in a crowd, even when working memory demands are low and the ensemble information is not directly task-relevant.

Keywords: Ensemble perception; Scenes; Valence.

Fig. 1

Example trials from Part I (left) and II (right). Participants rated the emotional valence of a single image in Part I and then a cued image from a set of four in Part II

Fig. 2

Percent of trials in which emotional bias was in the expected direction. Bias in the expected direction was calculated by determining the percent of cued image ratings that shifted toward the mean of the distractor image ratings. ‘No Bias’ line determined by Monte Carlo simulations. Error bars represent one standard error of the mean

Fig. 3

Example trial from Part II. Participants saw an upright image that was cued after 1 second along with inverted distractor images

Fig. 4

Example trial from Part II. Participants saw four scrambled images, one of which was unscrambled and cued after 1 second

Fig. 5

Correlation between the average ratings of the original images (x-axis) and the average ratings of the scrambled images (y-axis)