Recognition memory and the orienting response: an analysis of the encoding of pictures and words.

Three experiments were designed to investigate the role of the orienting response (OR) in the recognition memory for pictures and words. In the first experiment (n = 60), pictures which were shown to have a high frequency of correct recognition in an independent analysis of recognition memory evoked larger initial ORs than words and low recognition frequency pictures. In experiment 2 (n = 56) subjects participated in the recognition memory task and then they received 12 repetitions of a picture or word stimulus which they either recognized or failed to recognize. The magnitude of the initial electrodermal OR was larger for the not recognized than for the recognized stimuli. This finding, which is a stimulus priming effect, was replicated in experiment 3 (n = 40). In experiments 1 and 2, recovery of the OR following a habituation series was induced by a change to the alternate representational form of the stimulus. Differences between the picture-word and word-picture transitions were not consistent between experiments. Overall, the experiments indicate that OR magnitude is influenced by the availability of the stimulus memory trace, with increased amplitude determined by less accessible memory traces.