Ensemble perception of facial attractiveness

Abstract

Ensemble perception, the extraction of a statistical summary of multiple instances of a feature, enables efficient processing of information. Here we investigated whether ensemble representations can be formed for facial attractiveness, a socially important complex feature. After verifying that our face stimuli produced by geometric morphing represented a valid continuum of attractiveness (Experiment 1), we asked participants to compare the average attractiveness of four faces with a single probe face. Whether the four faces were homogeneous or heterogeneous resulted in highly similar performance levels, suggesting the visual system could extract an ensemble representation of the attractiveness of a heterogeneous group of faces. Statistical simulations with human-level bias and noise indicated participants did not rely on subsampling one random face or the most/least attractive face from the array (Experiment 2). Ensemble perception of facial attractiveness was not affected by variance in the stimulus array (Experiment 3), did not depend on memory of individual faces in the array (Experiment 4), and could be extended to larger arrays with faces asymmetrically distributed around the set mean (Experiment 5). Our findings give further evidence to the prevalence of perception of statistical regularities in vision.

Limited evidence of hierarchical encoding in the cheerleader effect

“…Similarly, Luo and Zhou 44 also identified limitations to the hierarchical encoding account of the cheerleader effect, while investigating ensemble coding in judgments of facial attractiveness. Notably, that observers showed a tendency to extract ensemble representations that were slightly less attractive than average attractiveness of each group 44 . Specifically referring to the cheerleader effect, Luo and Zhou 44 reasoned that if the ensemble representation was perceived to be highly attractive, observers should systematically overestimate, not underestimate, the average attractiveness of the group.…”

“…Therefore, even though the current study is the first to directly investigate the underlying cause of the cheerleader effect, the limitations of the hierarchical encoding mechanism have been alluded to previously 16,44 . Our findings provide the strongest evidence to date that hierarchical encoding appears to only make a minimal contribution to the cheerleader effect, if any at all.…”

“…The ensemble coding of expression occurs rapidly, as observers can accurately identify the average expression shown by a group of 16 faces that has been presented for just 50 ms 35,36,42 . In addition to rapidly extracting the average emotion 35,36,41 and identity 37-39 from groups of faces, observers can accurately summarise other characteristics of faces, including average ethnicity and dominance 43 , gender 36 , and attractiveness 44 . Although ensemble coding allows observers to rapidly extract the 'gist' of complex visual scenes 21,22,26 , this process influences the accuracy with which the characteristics of individual items from the group are remembered 23,24,45 .…”

Contrast Effect of Facial Attractiveness in Groups

“…The evaluation of the central face was assimilated in the attractiveness of the surrounding faces, and the face in the middle was rated less attractive (Geiselman et al, 1984). This is in line with observers' bias toward the average attractiveness of the group by implicitly extracting information on it, when the target face is surrounded by a group of faces with heterogeneous degrees of attractiveness (Luo and Zhou, 2018). Rodway et al (2013) found both greater assimilation and greater contrast, with attractive faces perceived less attractive regardless of the attractiveness of the surrounding faces, and unattractive faces perceived more attractive only when flanked by other unattractive faces.…”

Ensemble statistics of faces

“…It should be noted that we are not claiming ensemble coding cannot occur when there is no variance in the scene. For example, Luo and Zhou (2018) recently showed variability is not required for ensemble perception of facial attractiveness to arise.…”