ABSTRACT
A full understanding of the visual environment requires the ability to discriminate objects that vary along many dimensions, including size, shape, and brightness. Also required are levels of processing sufficient to resolve the fine details that define individual objects. Additionally, in order to manipulate and move through the environment, one must perceive the visual boundaries between self and surroundings. Throughout life, our competence in understanding and manipulating our environment is at least partly limited by our ability to visually discriminate the objects that surround us.
