Effects of aging and IQ on item and associative memory

  • Ratcliff R
  • Thapar A
  • McKoon G
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The effects of aging and IQ on performance were examined in 4 memory tasks: item recognition, associative recognition, cued recall, and free recall. For item and associative recognition, accuracy and the response time (RT) distributions for correct and error responses were explained by Ratcliff's (1978) diffusion model at the level of individual participants. The values of the components of processing identified by the model for the recognition tasks, as well as accuracy for cued and free recall, were compared across levels of IQ (ranging from 85 to 140) and age (college age, 60 –74 years old, and 75–90 years old). IQ had large effects on drift rate in recognition and recall performance, except for the oldest participants with some measures near floor. Drift rates in the recognition tasks, accuracy in recall, and IQ all correlated strongly. However, there was a small decline in drift rates for item recognition and a large decline for associative recognition and cued recall accuracy (70%). In contrast, there were large effects of age on boundary separation and nondecision time (which correlated across tasks) but small effects of IQ. The implications of these results for single-and dual-process models of item recognition are discussed, and it is concluded that models that deal with both RTs and accuracy are subject to many more constraints than are models that deal with only one of these measures. Overall, the results of the study show a complicated but interpretable pattern of interactions that present important targets for modeling. In memory research, there is general agreement on a distinction between item and associative information. In tasks that tap item information, participants are asked to decide whether a test item was presented earlier in an experiment. In tasks that tap associative information, participants are asked to decide whether two items of a pair were presented earlier in the same pair or in a different pair. This distinction has a long history in experimental psychology. Murdock (1974), for instance, made the distinction a centerpiece of his approach to memory, and he reviewed much of the earlier work separating these two forms of memory. More recently, a number of studies have provided compelling evidence for the distinction

Author-supplied keywords

  • Diffusion model
  • IQ and age
  • Item and associative recognition
  • Memory
  • Reaction time

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  • Roger Ratcliff

  • Anjali Thapar

  • Gail McKoon

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