Memory span and short-term memory capacity: A developmental study

A memory span task involving series conditions comprised of several different types of material was administered to children from three grade levels (7–12 years of age). As expected, age differences were strongly affected by type of material, with two conditions (consonant letters, words) intended to restrict opportunities for chunking yielding age differences that were negligible, and one condition (consonant-vowel letters) constructed to maximize sequential probability yielding age differences that were large. This finding renders less plausible the popular notion that capacity increases with age, and suggests that age differences in memory span reflect chunking processes. Additional findings, which indicate that age differences in memory span are affected by method of presentation and stage of practice, suggest that these variables should be considered in studies aimed at estimating children's memory capacity.     

Conditions affecting retention test performance: A developmental study

Developmental studies of retention have yielded remarkably diverse results: however, it is widely assumed that retention ability increases with age. This study examined this assumption by investigating some of the conditions that might affect retention test performance in third graders and tenth graders. The most important results were the absence of age differences in proportionalized short-term retention, despite substantial differences in the number of items learned, and significant age differences in long-term retention only between groups that had received a different number of learning trials. These and other results suggest that age differences in retention test performance occur only when age is confounded with degree of learning. In short, there do not appear to be any age differences in retention per se.     

An investigation of the role of scale values in the DS/AHP method of multi‐criteria decision making

DS/AHP is a method of multi‐criteria decision making based on the Dempster–Shafer theory of evidence and the analytic hierarchy process. Central to the utilization of DS/AHP is the composing of preference judgements on identified groups of decision alternatives (DA) across a number of criteria against all the DA present in the problem in question. This paper exposits a series of results whose objectives are to aid in the development of an effective set of preference scale values for use within DS/AHP. These results relate directly to the concomitant level of ignorance (uncertainty) with the judgements made on a single criterion. Two particular directions of investigation are undertaken, firstly in determining the necessary number of scale values available and secondly finding the necessary differences between scale values, dependent on whether an arithmetic or geometric progression is the basis for the scale values. Through an example, the implications and utilization of these results within DS/AHP are illustrated. Copyright © 2003 John Wiley & Sons, Ltd.