Holistic processing for bodies and body parts: New evidence from stereoscopic depth manipulations

Abstract

Although holistic processing has been documented extensively for upright faces, it is unclear whether it occurs for other visual categories with more extensive substructure, such as body postures. Like faces, body postures have high social relevance, but they differ in having fine-grain organization not only of basic parts (e.g., arm) but also subparts (e.g., elbow, wrist, hand). To compare holistic processing for whole bodies and body parts, we employed a novel stereoscopic depth manipulation that creates either the percept of a whole body occluded by a set of bars, or of segments of a body floating in front of a background. Despite sharing low-level visual properties, only the stimulus perceived as being behind bars should be holistically Bfilled in^via amodal completion. In two experiments, we tested for better identification of individual body parts within the context of a body versus in isolation. Consistent with previous findings, recognition of body parts was better in the context of a whole body when the body was amodally completed behind occluders. However, when the same bodies were perceived as floating in strips, performance was significantly worse, and not significantly different, from that for amodally completed parts, supporting holistic processing of body postures. Intriguingly, performance was worst for parts in the frontal depth condition, suggesting that these effects may extend from gross body organization to a more local level. These results provide suggestive evidence that holistic representations may not be Ball-or-none,^but rather also operate on body regions of more limited spatial extent.

Early Brain Damage Affects Body Schema and Person Perception Abilities in Children and Adolescents with Spastic Diplegia

“…In particular, face and body stimuli are processed using configural and holistic processing, as revealed, respectively, by the inversion [59, 112] and the composite illusion [78, 79] effects. Although the presence of composite illusion for body stimuli is still controversial [65–67, 76, 113], our results support the reliability of both effects in body perception. Notably, we found these effects in a pediatric population, suggesting an early refinement of perceptual processes for bodies [114] as it has been found in infancy for faces [115–117].…”

“…While configural processing consists in the detection of first-order and second-order relations among features, holistic processing refers to the perception of a social stimulus as a whole and not as a combination of single features [68]. Indeed, it represents a more refined perceptual ability tailored to specific social stimuli such as bodies and faces, facilitating identity and emotion recognition [75, 76]. Holistic processing is revealed by the composite illusion effect [66, 77, 78]; two identical top halves of bodies or faces combined with two different bottom halves are perceived as being different when they are aligned (with respect to vertical axis), but not when they are misaligned [79].…”

Body inversion effect in monkeys

“…Unlike most other, nonsocial visual objects, inverted body postures tend to be much more difficult to discriminate or identify than upright ones. This body inversion effect suggests that our visual processing of bodies depends on the overall spatial relationships among body parts (configuration) rather than individual body parts [ 7 , 11 ]. Previous studies have compared humans’ body inversion effect with the face inversion effect [ 10 , 12 ], tried to clarify the critical requisite for the effect [ 13 – 16 ], and examined neural substrates [ 17 – 19 ].…”

Holistic processing of body stimuli: Evidence of body composite illusion in adults and children.

“…This methodological choice ensured us that the results were not affected by an own-race bias widely documented for facial stimuli (Wong et al, 2020), but prevented us from investigating the presence of this effect for bodily stimuli, which is worth to be explored by future research. Recent studies have provided evidence of holistic processing for body stimuli by adopting a novel paradigm involving a stereoscopic depth manipulation (Harris et al, 2016; Reed et al, 2015). Even if this technique may open new scenarios for studying visual body perception, our results suggest that a classical composite illusion paradigm can reliably probe holistic body processing across age as it does for faces (Bruce et al, 2010; Richler et al, 2012).…”

“…Thus, in a same-different judgment task, the weaker the performance for stimuli presented aligned compared with nonaligned ones, the stronger the composite illusion and the reliance on holistic processing. Whereas holistic processing has been widely documented for faces (for a review and meta-analysis: Richler & Gauthier, 2014), literature on the body composite illusion is more controversial, with studies suggesting similarities in perceptual strategies for faces and bodies (Harris et al, 2016; Reed et al, 2015; Willems et al, 2014) and others reporting no evidence of holistic processing for body stimuli (Soria Bauser et al, 2011, 2015). This inconsistent evidence calls for further investigation on the use of holistic processing for body stimuli.…”