Abstract
Biases in face processing reflect experiential, attentional, and motivational priorities for recognizing kinds of faces. The own species bias (OSB) emerges in infancy and reflects enhanced recognition of human compared to animal faces (typically non-human primate). However, perceptual expertise for pet faces is more likely than for non-human primate faces, and there is strong motivation to individuate pets. Evaluating the behavioral and neural basis of the OSB with dog/cat faces provides an opportunity to test proposed mechanisms that may drive this bias, particularly in a developmental context. The current study examined brain activation within the core and extended regions underlying face recognition in 24 adolescents (ages 12-17) and 24 emerging adults (ages 18-24). Participants completed a 1-back memory task while viewing animal faces, human faces, and objects, during fMRI. Human and animal face ROIs were identified separately in individual participants throughout the regions of the face processing network. The number of contiguously active voxels (FDR q < .05) and the magnitude of activation for the oppositive face category (i.e., animal face activation in human face ROI) were quantified for each ROI in each hemisphere. We observed an OSB in the size of the ROIs (human > animal), in some, but not all the regions within the face processing network (i.e., bilateral OFA, FFA1, FFA2), for both adolescents and adults. There was no OSB in the pFG size. The magnitude of activation within these ROIs also reflected an OSB with weaker responses to the oppositive face category. Importantly, we observed a positive association between age and ROI size and magnitude of activation, only for human-face ROIs. These results suggest that in the ventrovisual pathway there is posterior-anterior progression of perceptual attunement in the neural representation of human faces that is established in adolescence and becomes increasingly more fine-tuned toward human faces.