Memory of Ensemble Representation Was Independent of Attention

Abstract

The hierarchical view of working memory suggested that object ensemble could also be stored into working memory by treating ensemble properties as single “unit.” However, it remains unclear whether ensemble representation in working memory is vulnerable to attention demanding. The present study designed a dual-task paradigm constituting of a memory retaining task and an attention-demanding arrow flanker task. Participants were firstly presented an array (4 or 9) of facial images with neutral expressions and then shown a left- or right-orientated arrow surrounded by four congruent or incongruent oriented arrows or short lines. Participants judged the orientation of the target arrow and then indicated whether a probe facial image was present or absent in the preceding facial array. The probe face consisted of four conditions: (1) a morphed average face of prior face set, (2) a morphed average face of another face set, (3) an exemplar face of prior set, and (4) an exemplar face of another face set. Results confirmed that participants implicitly coded the average facial image of preceding set and retained in working memory. More importantly, the memory representation of ensemble property (e.g., average facial identity) was independent of flanker type. In sum, this study provided further evidence of the hierarchical view of working memory and suggested that attention was not a pre-requisite for the retaining of ensemble properties in working memory.

Individual Faces Were Not Discarded During Extracting Mean Emotion Representations

“…Based on these previous findings, it seems that the ensemble coding of facial identity information could be unique. However, Leib et al (2014) found that the precision of mean identity representations improved as the set size increased, which is inconsistent with the findings reported by Neumann et al (2017) and Peng et al (2019) . We propose that the different results might be due to stimulus variance in a set.…”

“…We propose that the different results might be due to stimulus variance in a set. Neumann et al (2017) and Peng et al (2019) used more than 40 faces with different identities as the experimental material, while Leib et al (2014) employed morphing stimuli created from three faces, and the present study used morphing stimuli created from two faces. Therefore, the number of faces used in the different studies may have caused different stimulus variances in a set.…”

“…Thus, the ensemble coding of facial emotion and identity information might involve different processes. Peng et al (2019) demonstrated that when the number of faces in a set was increased from four to eight, the precision of both the mean and individual identity representations declined. Based on these previous findings, it seems that the ensemble coding of facial identity information could be unique.…”

“…To adjust the attentional resources allocated to individual items, some studies varied the set size and found that the precision of the mean representation was affected by the set size ( Leib et al, 2014 ; Peng et al, 2019 ). This finding suggests that the extraction of a mean representation might depend on the processing of individual items.…”

Implicit processing during inattentional blindness: A systematic review and meta-analysis

“…This is the case even if explicit ensemble representations do not demand (explicit or implicit) representation of individual features (Ward et al, 2016). The numerous observations of ensemble representations formed in the absence of attention (e.g., Corbett & Oriet, 2011;Peng et al, 2019;Whitney & Yamanashi Leib, 2018) provide empirical support to this suggestion.…”