Abstract
Object animacy is an important organizing principle of the ventral temporal cortex (VTC) object representations, but the exact features driving this organization are still being investigated. Previous studies have shown that visual features such as overall body shape do not fully explain animacy information in VTC (Proklova et al, 2016, Bracci et al, 2016). However, inanimate objects such as toys or robots have recently been shown to be represented similarly to animals in VTC (Bracci et al., 2019; Contini et al., 2019), suggesting that this region might be sensitive to some diagnostic features that these objects share with animals, rather than animacy per se. One possible feature that has not been controlled for in previous studies is the presence of the face. Animate-like objects such as toys and robots often share this feature with animals, which could explain why they are represented similarly to animals in the VTC.
In this study, we directly examined the role of faces in the animate/inanimate distinction in VTC representations using fMRI. To do this, we created a stimulus set in which animacy and face presence were orthogonalized. This stimulus set included images of faceless animals, animals with faces, and inanimate objects, organized into triplets based on an overall shape similarity. We performed representational similarity analysis (RSA) comparing the representational content of VTC with several models (animacy, face presence, visual similarity.) As expected, we observed significant correlation between neural dissimilarity in the VTC and the animacy model. Interestingly, this correlation was lower but still significant even after all animals with faces were removed from the analysis, showing that even animals without a distinct face were represented differently from inanimate objects in the VTC. Our results suggest that faces are important but not necessary feature for animate/inanimate distinction in the VTC.