Iconic Memory

Investigations of the processing of brief visual displays, and the explanation of such processing in terms of iconic memory, are reviewed. It is concluded that the concept of a pre-categorical sensory memory for visual material remains tenable. The ability to report material from brief visual displays is seen as depending upon parallel (and perhaps unlimited) transfer from iconic memory to a post-categorical memory mode, followed by a limited (and perhaps serial) transfer to an output stage. Decisions about, or responses to, items can only be made when they are in the output stage. Because transfer out of the post-categorical mode can be performed on the basis of pre-categorical stimulus features, pre-categorical information about items in the postcategorical mode must be accessible. One way in which this would be possible is if the transfer of an item into the post-categorical mode takes the form of the creation, to represent the item, of a temporary file of information including both pre-categorical and post-categorical features of the item. Any such feature can be used as the basis for selecting the item for transfer from the post-categorical mode to the output stage, for subsequent decision or report.