Serial dependence promotes the stability of perceived emotional expression depending on face similarity

Abstract

Individuals can quickly and effortlessly recognize facial expressions, which is critical for social perception and emotion regulation. This sensitivity to even slight facial changes could result in unstable percepts of an individual's expression over time. The visual system must therefore balance accuracy with maintaining perceptual stability. However, previous research has focused on our sensitivity to changing expressions, and the mechanism behind expression stability remains an open question. Recent results demonstrate that perception of facial identity is systematically biased toward recently seen visual input. This positive perceptual pull, or serial dependence, may help stabilize perceived expression. To test this, observers judged random facial expression morphs ranging from happy to sad to angry. We found a pull in perceived expression toward previously seen expressions, but only when the 1-back and current face had similar identities. Our results are consistent with the existence of the continuity field for expression, a specialized mechanism that promotes the stability of emotion perception, which could help facilitate social interactions and emotion regulation.

Visual serial dependence in an audiovisual stimulus

“…Cicchini et al (2017) showed evidence of positive serial dependence only for participants comparing similar stimuli. Likewise, Liberman et al (2018) confirmed that serial dependence was only present when participants reported facial expressions within the same identity (i.e., same genders). In our Experiments 1 and 2, there was a subtle difference between the pitch of the stimulus vowels and the response vowels, of 2 Hz.…”

“…Vowels were synthesized and morphed along a circular continuum with the sounds /u:/, / :/, and / :/ as anchors ( Figure 1a) using a modified vowel function from the MATLAB audio toolkit (Smith, 2011). The morphed stimulus space was analogous to a morphed continuum of three distinct faces used in previous studies (Liberman et al, 2014;Liberman et al, 2018). Vowels were synthesized with a fundamental frequency of either 122 Hz (Experiments 1 and 2) or 120 Hz (Experiment 3), at a sampling frequency of 44.1 kHz.…”

“…Expectation may facilitate visual processing by allowing us to more readily detect or recognize a stimulus (Summerfield & Egner, 2009). In these serialdependence experiments, participants are presented with the same kind of information throughout the experiment-for example, always judging Gabor orientations Fritsche et al, 2017) or faces (Liberman et al, 2014;Liberman et al, 2018). Participants in such tasks become accustomed to encoding the same stimulus feature and performing the same adjustment task throughout the experiment.…”

Context information supports serial dependence of multiple visual objects across memory episodes

“…This bias was enhanced by spatial and temporal item proximity as well as by attentional selection and was termed 'serial dependence'. It has since been observed for other modalities, including facial identity and expression 4,5 , spatial positions 6,7 , numerosity [8][9][10] or ensemble representations 11 . As serial dependence reduces differences in the appearance of similar consecutive objects, it has been interpreted as promoting perceptual stability and continuity of a visual object over time 3 .…”

Perceptual decisions are biased toward relevant prior choices

“…Rather, they are substantially influenced by other factors, such as context and prior experience (Kersten et al, 2004;Bar, 2004;Panichello et al, 2013;Clark, 2013;de Lange et al, 2018). Notably, our perceptual decisions are biased by preceding perceptual events -a phenomenon, termed 'serialdependence', that has garnered considerable recent interest Liberman et al, 2014;Taubert et al, 2016;Alexi et al, 2018;Liberman and Manassi, 2018).…”