ABSTRACT
A review of some experiments demonstrating sequential effects in serial choice-reaction tasks suggests that there are two distinct ways in which the presentation of one display may facilitate perceptual processing of another: (1) A current display may be compared for physical identity with its predecessor. Detection of identity will then allow a very fast response. (2) When successive signals are not physically identical, but nevertheless belong to a set to which the same response is made, recognition of the first may “prime” complex processes involved in recognition of the second. Transition analyses of visual search tasks show that in such situations, also, facilitation effects observed may be described under one or the other of these two headings. Further work on sequential effects shows that “a two-stage model” of perceptual processing, implying that successive signals are always compared for physical identity (“matching”) as well as being subjected to more complex forms of perceptual processing (“analysis”), may be of general use in interpreting perceptual processing in sequential tasks.
