False positives in recognition memory produced by cohort activation

Cohort theory in spoken-word recognition assumes that a cohort of word candidates consistent with incoming sensory information is activated implicitly as a spoken sound stimulus unfolds over time. Five experiments examined implications of this internal-generation-of-words mechanism. In Experiments 1 and 2, a “base” word was disqualified (the sensory information was no longer consistent with the word) either early or late in the presentation of a spoken stimulus. On a later recognition-memory test, significantly more false-positive errors occurred to base words following presentations of study items that had late, compared to early, disqualification points. Experiments 3–5 tested whether this phenomenon could be accounted for in terms of overlapping features between non-word stimuli and their base words or in terms of a post-identification processing mechanism. Experiment 3 replicated Experiments 1 and 2, and demonstrated that differences in early and late disqualification points for non-word targets, unlike word targets, were not related to false-positive recognition memory errors. The study inter-item interval in Experiment 4 was reduced to 1 s to minimize the role of post-identification processing activities, and the results for both word and non-word targets were consistent with Experiment 3. A word-association task in Experiment 5 revealed that the late non-word derivations used in this research were on the average more effective stimuli than the early non-word derivations in eliciting their base words. However, even when comparisons were restricted to item sets with early and late non-words that were equally effective in eliciting base words, false-positive recognition memory errors to target words were higher following prior presentations of their late derived non-words than following prior presentations of their early derived non-words.