Presenter:  Angela Nelson
Presentation type:  Talk
Presentation date/time:  7/26  10:30-10:55
 
A Contextual Diversity Account of Frequency Effects
 
Angela Nelson, Indiana University
Richard Shiffrin, Indiana University
 
Frequency effects in memory and perceptual tasks have been shown to occur for novel items trained to differential degrees (Nelson & Shiffrin, 2006). Because each novel item is randomly assigned to a frequency category, these results are inconsistent with the REM model account of frequency (Shiffrin & Steyvers, 1997), which assumes that higher frequency items are composed of higher frequency features. We present a new model through which the lexical representation of the novel items develops over training. Each item's lexical representation is composed of features that are stored not only from the item itself, but also from the item's contextual surroundings. Since the higher frequency items are seen in a larger variety of contexts than lower frequency items, the higher frequency items develop a more diverse representation in the lexicon. The model is shown to account for the frequency effects found by Nelson and Shiffrin (2006).