Visual selection and response selection without effector selection in tasks with circular arrays.

Charles Eriksen and colleagues conducted influential visual-search experiments with circular arrays for which the responses were either vocal naming or unimanual left-right switch movements. These methods have the advantages of the stimuli being equidistant from a centered fixation point and allowing study of visual selection and response selection when effector selection is not required, as in the more typical case in which responses are key presses of distinct fingers. Other researchers have used similar spatial arrangements, but with aimed movements of the limb or of a mouse-controlled cursor to study effects of stimulus identification, visual search, spatial stimulus-response compatibility, response-effect compatibility, and practice/transfer in isolation and jointly. We systematically review studies in these areas that include visual selection and response selection and execution, and examine implications of their results for the role of effector selection. Also, we illustrate that as one moves from simpler to more complex tasks, the results are consistent with a basic information-processing framework in which stimulus identification and selection of a target response location are distinct from selecting, planning, and moving an effector to the targeted location.