A shape-based account for holistic face processing.

Abstract

Faces are processed holistically, so selective attention to 1 face part without any influence of the others often fails. In this study, 3 experiments investigated what type of facial information (shape or surface) underlies holistic face processing and whether generalization of holistic processing to nonexperienced faces requires extensive discrimination experience. Results show that facial shape information alone is sufficient to elicit the composite face effect (CFE), 1 of the most convincing demonstrations of holistic processing, whereas facial surface information is unnecessary (Experiment 1). The CFE is eliminated when faces differ only in surface but not shape information, suggesting that variation of facial shape information is necessary to observe holistic face processing (Experiment 2). Removing 3-dimensional (3D) facial shape information also eliminates the CFE, indicating the necessity of 3D shape information for holistic face processing (Experiment 3). Moreover, participants show similar holistic processing for faces with and without extensive discrimination experience (i.e., own- and other-race faces), suggesting that generalization of holistic processing to nonexperienced faces requires facial shape information, but does not necessarily require further individuation experience. These results provide compelling evidence that facial shape information underlies holistic face processing. This shape-based account not only offers a consistent explanation for previous studies of holistic face processing, but also suggests a new ground-in addition to expertise-for the generalization of holistic processing to different types of faces and to nonface objects.

Holistic processing of static and moving faces.

“…Consistent with this dual-route hypothesis, holistic processing of faces can be reduced or eliminated by disrupting object-based grouping of facial parts, despite humans having life-long experience in individuating faces (Curby et al, 2013;Zhao et al, 2016b).…”

“…In accordance with the declaration of 1 Our sample size is primarily based on previous studies in the literature and our own research using the same paradigm (e.g., Zhao et al, 2014;2016a, 2016b. A priori power analysis using G*Power 3 (Faul, Erdfelder, Lang, & Buchner, 2007) indicated that a total number of 48 participants (24 per group) are required to detect an interaction between holistic processing and face type, with a medium effect size ηp 2 = .06 (or f = .25), α = .025, power (1-β) = .90, and correlations among measures ρ = .30 (based on a meta-analysis; .…”

“…However, if holistic face processing is supported by perceptual grouping due to either observers' experience with dynamic faces or face-based grouping cues (e.g., 3D facial shape, Zhao et al, 2016aZhao et al, , 2016b, the presence of rigid facial motion should not disrupt holistic processing. The reason is that rigid facial motion should not eliminate such perceptual grouping.…”

“…Besides the two influential theories mentioned above, recent studies suggest that both object-based (i.e., bottom-up route) and experience-driven (i.e., top-down route) perceptual grouping contribute to holistic processing (Zhao, Bülthoff, & Bülthoff, 2016a, 2016b; see also Curby, Entenman, & Fleming, 2016;Curby, Goldstein, & Blacker, 2013;Zhou, Cheng, Zhang, & Wong, 2012). Consistent with this dual-route hypothesis, holistic processing of faces can be reduced or eliminated by disrupting object-based grouping of facial parts, despite humans having life-long experience in individuating faces (Curby et al, 2013;Zhao et al, 2016b).…”

“…Answers to these questions will not only help reconcile the discrepancies between mixed findings about holistic processing of moving faces, but they will also help address one fundamental question about current theories of holistic processing-whether they can be generalized to moving stimuli or apply only to static faces and objects. Moreover, determining whether holistic and part-based processing are similarly involved between static and rigidly moving faces may also help clarify what is holistic representation of faces (McKone & Yovel, 2009;Piepers & Robbins, 2012;Rossion, 2013) and what type of facial information underlies holistic processing (Rossion, 2013;Zhao et al, 2016b). …”