This work aims to elucidate the mechanisms that allow us to recover the three-dimensional (3D) structure of the world, and in particular, how the position of light affects our ability to estimate the 3D shape of shaded objects. To estimate the 3D shape of an object from its 2D retinal image, observers use various depth cues. Shading is one such cue which informs us of the local surface orientation of objects by exploiting the fact that surfaces facing the light-source are brighter than those facing away. Observers assume, by default, that the light is coming from an above left direction. My research uses a range of methods such as human psychophysics, functional brain imaging, and brain stimulation, in different populations, such as ageing, young children and patients with focal brain lesions, to understand how the brain generates a representation of the light source assumed direction and to what extent this assumption reflects the contribution of innate or acquired factors.

We investigate the cognitive strategies, and neural mechanisms, that allow us to explore the environment efficiently. In the past we have examined directly the neural signals associated with endogenous shifts of spatial attention using fMRI (Sapir, d’Avossa, McAvoy, Shulman, & Corbetta, 2005), and more recently have investigated the effects of endogenous and exogenous spatial cues on detection of stimuli in the environment (Burnett, d'Avossa, & Sapir, 2013; Burnett, d'Avossa, Close, & Sapir, 2016; Burnett, d’Avossa, & Sapir, 2018).