Tapan Gandhi

Sinha Lab, MIT

Face Perception: Nature or Nurture?

 

Understanding brain function is widely acknowledged to be one of the great scientific frontiers of the 21st century. The impact of this undertaking will be far reaching, encompassing basic science, engineering and clinical practice. My work thus far has examined brain function in healthy adults and also its development and disorders. In this talk, I will focus on studies of development that have not only yielded novel insights about brain plasticity, but are also enlighten the nature-nurture debate of face perception. The human visual system is remarkably adept at localizing faces in complex natural scenes. It is unclear whether this skill has innate roots or is acquired through visual experience. Operational challenges involved in working with newborn infants make this a difficult issue to address definitively. Here we explore this question in the context of late sight onset. Project Prakash has provided us with a unique opportunity to work with individuals deprived of pattern vision since birth. We tested face-learning skills of few newly sighted children, ranging in age from 8 to 23 years. We found that the newly sighted children showed poor face learning skill immediately after sight onset, favoring an empirical, rather than nativist, account of skill acquisition. Furthermore, longitudinal assessment of performance showed that the brain retains an impressive degree of plasticity even after being deprived of vision for several years. These results suggest that plasticity for face learning is also preserved even late in childhood. Furthermore, the pattern of performance observed across different stimulus conditions has implications for understanding the mechanisms that subserve face perception soon after sight onset.