In the SIMPLE model (Scale Invariant Memory and Perceptual Learning), performance on memory tasks is determined by the locations of items in multidimensional space, and better performance is associated with having fewer close neighbors. Unlike most previous simulations with SIMPLE, the ones reported here used measured, rather than assumed, dimensional values. The data to be modeled come from an experiment in which younger and older adults recalled lists of acoustically confusable and non-confusable items. A multidimensional scaling solution based on the memory confusions was obtained. SIMPLE accounted for the overall difference in performance both between the two age groups and, within each age group, the overall difference between acoustically confusable and non-confusable items in terms of the MDS coordinates. Moreover, the model accounted for the serial position functions and error gradients. Finally, the generality of the model's account was examined by fitting data from an already published study. The data and the modeling support the hypothesis that older adults' memory may be worse, in part, because of altered representations due to age-related auditory perceptual deficits.
KeywordsMemory; Memory models; Aging and memory Brown, Neath, and Chater (2002; see also Neath and Brown 2006) proposed a local distinctiveness model of memory called SIMPLE (Scale Invariant Memory and Perceptual Learning) in which memory retrieval, regardless of the paradigm, is viewed as discrimination of items in terms of their location along one or more dimensions. Items with fewer close neighbors on the relevant dimensions will be better remembered than items with more close neighbors. In a typical simulation, the researcher makes an assumption about what the relevant underlying dimensions should be. For many simulations, the choice of dimensions is relatively uncontroversial; for example, for free recall, the primary dimension is typically assumed to be time (Brown et al., 2002) and for absolute identification of tones, it is assumed to be frequency