Covert orienting within peripersonal and extrapersonal space: young adults.

Covert orienting within peripersonal (near) and extrapersonal (far) space was investigated in a large sample of young adults. The participants made speeded responses to targets in a simple, go/no-go detection task. Stimuli, equated for eccentricity and size, were presented at two distinct distances from the observer, representing peripersonal space and extrapersonal space. Within each distance condition cues and targets were presented at the four corners of an imaginary square allowing assessment of the influence of attention upon targets presented in the upper and lower as well as left and right visual fields. In the neutral condition lower field targets had a small advantage over upper field targets. This effect was also observed under cued conditions. When presented in peripersonal space, near targets benefited more from valid cuing than did targets in the other conditions. This pattern is discussed in terms of Previc's [Behav. Brain Sci. 13 (1990) 519] model of visual field specialization.