The recollection component of recognition memory as a function of response confidence: an event-related brain potential study

The recollection component of recognition memory as a function of response confidence: an event-related brain potential study

The aim of the current series of experiments was to further explore the boundary conditions of the recognition memory old/new effect in the context of the recognition/associative recall task (Rugg, Schloerscheidt, Doyle, Cox, & Patching, 1996). The study by Rugg et al. was replicated and extended by manipulating both the semantic relatedness between study items and the timing of recall. Eventrelated potentials (ERPs) were recorded from 17 scalp electrode sites during performance of a recognition/associative recall task. Forty participants were visually presented with four blocks of 50 word pairs which were either unrelated (Experiments 1 and 2) or weakly semantically related (Experiments 3 and 4). Participants were instructed to form an association between the members of each word pair. At test, the first members of each pair were visually presented intermixed with a similar number of unstudied items. Participants were required to discriminate (i.e., recognise) previously studied items (old) from new items. Participants were also required to recall the study associate for words judged old, and to provide confidence levels for each recognition decision on a 3-point scale. Recall was either immediate (Experiments 1 and 3) or delayed (Experiments 2 and 4). Relative to ERPs to new items, the ERPs elicited by words correctly recognised and for which the associate was correctly recalled exhibited a positive-going shift between 500-800 ms poststimulus onset. The effect was maximal at posterior temporal-parietal electrode sites (the parietal old/new effect). Although the effect was not lateralised to the left hemisphere, this result may be due to the variability in encoding strategies employed by the participants. Behavioural data consistently indicated that response confidence is confounded with response category. The ERP results also revealed that the old/new effect is not evident following the experimental control of response confidence, and that immediate recall is associated with a negative-going shift at posterior electrode sites between 800-1100 ms poststimulus onset. Manipulating the semantic relatedness between the word pairs did not influence the distribution of the old/new effect. The results are discussed in terms of the view that the parietal old/new effect reflects neural activity associated with the recollection of specific previous experiences, and may reflect retrieval processes supported by the medial temporal lobe memory system (Moscovitch, 1992, 1994; Squire, 1992; Squire, Knowlton, & Musen, 1993). It is suggested that future research extend the current findings by examining the influence of response confidence in alternative recognition memory paradigms.