Richer concepts are better remembered: number of features effects in free recall

*Research article by Ian S. Hargreaves, Penny M. Pexman, Jeremy C. Johnson and Lenka Zdrazilova Department of Psychology, Language Processing Lab, University of Calgary, Calgary, AB, Canada

Abstract

Many models of memory build in a term for encoding variability, the observation that there can be variability in the richness or extensiveness of processing at encoding, and that this variability has consequences for retrieval. In four experiments, we tested the expectation that encoding variability could be driven by the properties of the to-be-remembered item. Specifically, that concepts associated with more semantic features would be better remembered than concepts associated with fewer semantic features. Using feature listing norms we selected sets of items for which people tend to list higher numbers of features (high NoF) and items for which people tend to list lower numbers of features (low NoF). Results showed more accurate free recall for high NoF concepts than for low NoF concepts in expected memory tasks (Experiments 1–3) and also in an unexpected memory task (Experiment 4). This effect was not the result of associative chaining between study items (Experiment 3), and can be attributed to the amount of item-specific processing that occurs at study (Experiment 4). These results provide evidence that stimulus-specific differences in processing at encoding have consequences for explicit memory retrieval.

Keywords: semantic richness, free recall, memory

Executive Summary

Words vary on a large number of lexical dimensions that characterize factors such as their frequency of usage, or that refer to structural characteristics such as shape (orthography) and sound (phonology). Words, rather helpfully, also vary in meaning, and this variability can be captured by numerous semantic dimensions that influence the speed with which words can be recognized or categorized (Pexman et al., 2008). A vast word recognition literature has sought to characterize how orthographic, phonologic, and semantic dimensions interactively contribute to our ability to read. Consistently, researchers have shown that the variability of a given word along any or all of these dimensions is an important determinant in how that word is processed, manifesting in differences in reading times and accuracy (Yap and Balota, 2009). Words are also convenient stimuli for experiments, and are often utilized in memory research as they offer a well-defined minimal unit that can easily serve in recognition and free recall memory paradigms. This raises an interesting question: we know that there are many characteristics of individual words that shape how those words are processed, but do these item-specific differences influence subsequent memory when words are used as stimuli?

*To read the full article please search for Dr JJ's publication online