Prediction and judgment as indicators of sensitivity to covariation of continuous variables

The present study used both judgments of strength of relationship and measures of the ability to predict one variable from another to assess subjects’ sensitivity to the covariation of two continuous variables. In addition, one group of subjects judged strength of relationship after merely observing the presentation of 60 pairs of two-digit numbers, and a second group made strength judgments after being actively engaged in predicting one member of a pair when given the other. The prediction and judgment data provide different pictures of subjects’ sensitivity to covariation. The subjects were quite poor at estimating strength of relationship but, by some measures, good at predicting one variable from another. Judgments were not strongly influenced by whether subjects had previously engaged in overt prediction. The implications of these results for the literature on covariation estimation are discussed.     

Working memory(s).

Working memory is variously defined as a set of linked and interacting information processing components that maintain information in a short-term store (or retrieve information into that store) for the purpose of the active manipulation of the stored items. The purpose of the this Special Issue is to present data relevant to the question of the functional organization of working memory. In this Introduction we review the two models of working memory and suggest that some of the similarities may be more apparent than real. We further suggest that the two models describe different systems that are specialized for different kinds of stimuli and for different kinds of information processing.     

Age differences in working memory tasks: The role of secondary memory and the central executive system

Two experiments are reported in which age differences in working memory performance are explored. In the first study, young and older adults held 2, 3, 4, or 5 unrelated words in mind while verifying a single or complex sentence. An age-related decrement was found in subsequent serial recall of the words, and this decrement was larger with longer word lists. Experiment 2 confirmed the interaction between age and list length, using list lengths of 4, 6, and 8 words and a free-recall procedure. There was no interaction between age and divided attention in either experiment. Surprisingly, sentence complexity had a greater detrimental effect on recall in the younger group. The results are discussed in terms of articulatory rehearsal being augmented by using secondary memory in the case of younger subjects.     

Book reviews

Boff, K. R., Kaufman, L., & Thomas, J. P. (Eds.). Handbook of perception and human performance. Volume 11: Cognitive processes and performance. New York: John Wiley and Sons, 1986. ISBN 0-471-82957-9. £81.25.

Lynch, Synapses, circuits and the beginnings of memory. Cambridge, Mass: The MIT Press, 1986. Pp. 122. ISBN 0-262-121 14-X. £22.50.