Behind the face of holistic perception: Holistic processing of Gestalt stimuli and faces recruit overlapping perceptual mechanisms.

Holistic processing, demonstrated by a failure of selective attention to individual parts within stimuli, is often considered a relatively unique feature of the processing of faces and objects of expertise. However, face-like holistic processing has been recently demonstrated for novel line stimuli with salient Gestalt perceptual grouping cues. Further, disrupting such cues within face stimuli disrupts holistic face perception. There is evidence that holistic processing of these gestalt stimuli and faces does not overlap mechanistically in the same way as does the processing of faces and objects of expertise. However, the relationship between these different manifestations of holistic processing is unclear. We developed a task to probe whether a holistic processing-specific overlap occurs at an earlier, perceptual level between the mechanisms supporting processing of faces and strong gestalt stimuli. Faces and gestalt line stimuli were overlaid, and participants made part judgments about either the faces (Experiment 1) or line stimuli (Experiment 2) in a composite task indexing holistic perception. The data revealed evidence of reciprocal interference between holistic processing of line and face stimuli, with indices of holistic processing of face and line stimuli reduced when the overlaid stimuli were also processed holistically (e.g., intact line/face stimuli) compared with when the overlaid stimuli did not commandeer holistic processing resources (e.g., misaligned line/face stimuli). This pattern is consistent with a mechanistic overlap between the holistic perception of faces and gestalt stimuli. Our results support a dual-stimulus-based and experienced-based-pathway model of holistic processing, with face stimuli using both.