Interference and priming within and across visual fields in a lexical decision task

A lower-case target word or non-word was laterally presented by itself or simultaneously with an upper-case distractor word in the same or in the opposite visual field. The distractor words were either semantically associated or unrelated to the target. Subjects performed a lexical decision task on the target. Two kinds of selection within and across visual fields were investigated. Selection of an external target relevant for the response (filtering) and selection of an internal target by automatic priming. No lateral asymmetry was found for automatic priming. Filtering was equally efficient within hemispheres, but strongly asymmetrical across hemispheres. Unrelated distractor words presented to the right hemisphere interfered less with target processing in the left hemisphere than vice versa. Thus, all distractor words received equivalent semantic processing; those presented to the right hemisphere, however, were least costly to exclude from task-relevant processing in the left hemisphere.