There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
The dominant accounts of many visual illusions are based on experience-driven development
of sensitivity to certain visual cues. According to such accounts, learned associations
between observed two-dimensional cues (say, converging lines) and the real three-dimensional
structures they represent (a surface receding in depth) render us susceptible to misperceiving
some images that are cleverly contrived to contain those two-dimensional cues. While
this explanation appears reasonable, it lacks direct experimental validation. To contrast
it with an account that dispenses with the need for visual experience, it is necessary
to determine whether susceptibility to the illusion is present immediately after birth;
however, eliciting reliable responses from newborns is fraught with operational difficulties,
and studies with older infants are incapable of resolving this issue. Our work with
children who gain sight after extended early-onset blindness, as part of Project Prakash,
provides a potential way forward. We report here that the newly sighted children,
ranging in age from 8 through 16 years, exhibit susceptibility to two well-known geometrical
visual illusions, Ponzo [1] and Müller-Lyer [2], immediately after the onset of sight.
This finding has implications not only for the likely explanations of these illusions,
but more generally, for the nature-nurture argument as it relates to some key aspects
of visual processing.