THE EFFECT OF RATE OF PRESENTATION AND REPETITION ON VERBAL PERSEVERATIONS IN
APHASIA: IMPLICATIONS FOR PRIMING ACCOUNTS
Stephen J. Gotts (1), Antonio Incisa della Rocchetta (2) & Lisa Cipolotti (2)
(1) Dept. of Psychology, Carnegie Mellon University, Pittsburgh, PA.
(2) National Hospital for Neurology and Neurosurgery, London, England.
A verbal recurrent perseveration is the inappropriate repetition of a recent
utterance when a different response is expected (Sandson & Albert, 1984).
Several accounts have suggested that such perseverations result when processing
of the current stimulus is too weak or slow to dominate a recently primed
response (e.g. Cohen & Dehaene, 1998; Martin, et al, 1998; Plaut & Shallice,
1993). We present data from several picture-naming experiments conducted with
an anomic patient (E.B.) which require further specification of current
proposals. Small sets of pictures were repeatedly presented for naming at a
fixed response-stimulus interval (RSI), either fast (1 sec) or slow (10-15
sec). Consistent with existing priming accounts, perseverations were more
likely after one within-block repetition and when the current target name was
of low frequency. However, there was no difference in the number of
perseverations produced under a fast vs. slow RSI, and the rate of decay was
far slower with a slow RSI. We present a simple computational model of these
results which appeals to recent theories of the neural basis of priming
(Desimone, 1996; Wiggs & Martin, 1998) and a similar spacing effect observed
in the presynaptic depression of neurons (Byrne, 1982).
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This page last updated 13 January 1999.