Individual differences in ensemble perception reveal multiple, independent levels of ensemble representation.

Abstract

Ensemble perception, including the ability to "see the average" from a group of items, operates in numerous feature domains (size, orientation, speed, facial expression, etc.). Although the ubiquity of ensemble representations is well established, the large-scale cognitive architecture of this process remains poorly defined. We address this using an individual differences approach. In a series of experiments, observers saw groups of objects and reported either a single item from the group or the average of the entire group. High-level ensemble representations (e.g., average facial expression) showed complete independence from low-level ensemble representations (e.g., average orientation). In contrast, low-level ensemble representations (e.g., orientation and color) were correlated with each other, but not with high-level ensemble representations (e.g., facial expression and person identity). These results suggest that there is not a single domain-general ensemble mechanism, and that the relationship among various ensemble representations depends on how proximal they are in representational space.

Spatial limitations in averaging social cues

“…That is, there may be a specific mechanism for pooling gaze direction which pools outputs from these face specific regions. This would be consistent with research23 where the authors compared correlations between participants’ mean error for face averaging tasks with more basic tasks such as orientation and colour averaging. They found that participants’ error for the two face tasks was correlated although neither task was correlated with the low level tasks.…”

Differential hemispheric and visual stream contributions to ensemble coding of crowd emotion

“…Much behavioral evidence has been accumulated supporting this notion 6,7,11–15,21,99–103, but see 104 , although only a few recent fMRI studies have compared the neural representations of ensemble coding and individual processing 105–107 . Cant and Xu 105,106 showed that PPA and LO were preferentially engaged in texture perception and object processing, respectively; and Huis in’t Veld and de Gelder 107 showed the greater anticipatory and action preparation activity in the areas including IPL, SPL, SFG, and premotor cortex for interactive body movement of a group of panicked people, compared to an unrelated movement of individuals.…”

Ensemble coding of crowd emotion: Differential hemispheric and visual stream contributions

“…Different patterns of hemispheric lateralization for the crowd emotion vs. individual emotion processing suggest that they may rely on qualitatively distinct systems. Much behavioral evidence has been accumulated supporting this notion (e.g., Alvarez & Oliva, 2008;Ariely, 2001;Cant, Sun, & Xu, 2015;Chong et al, 2008;Chong & Evans, 2011;Chong & Treisman, 2005;Choo & Franconeri, 2010;Corbett & Oriet, 2011;Haberman, Brady, & Alvarez, 2015;Haberman & Whitney, 2010;Im & Halberda, 2013;Leib et al, 2012;Parkes et al, 2001, but see Myczek & Simons, 2008, although only a few recent fMRI studies have compared the neural representations of ensemble coding and individual processing (e.g., , 2017Huis in't Veld & de Gelder, 2015). Xu (2015, 2017) showed that PPA and LO were preferentially engaged in texture perception and object processing, respectively; and Huis in't Veld and de Gelder (2015) showed the greater anticipatory and action preparation activity in the areas including IPL, SPL, SFG, and premotor cortex for interactive body movement of a group of panicked people, compared to an unrelated movement of individuals.…”