Item repetition in short-term memory: Ranschburg repeated.

In serial recall from short-term memory, repeated items are recalled well when close together (repetition facilitation), but not when far apart (repetition inhibition; the Ranschburg effect). These effects were re-examined with a new scoring scheme that addresses the possibility that repetitions are distinct tokens in memory. Repetition facilitation and repetition inhibition proved robust, and were shown to interact with the temporal grouping of items (Experiment 1), which affected the probability of detecting repetition (Experiments 2A and 2B). It is argued that detection of a repetition is necessary for repetition facilitation, attributable to the tagging of immediate repetition, whereas the failure to detect or remember a repetition results in repetition inhibition, attributable to an automatic suppression of previous responses and a bias against guessing repeated items (Experiment 3). The findings are discussed in relation to models of short-term memory and the phenomenon of repetition blindness.