Processing resources and age differences in working memory

This study investigated the performance of young and old subjects on a modified version of the working memory task developed by Baddeley and Hitch (1974). Subjects were required to verify a set of sentences of varying complexity while they repeated aloud zero, two, or four words. The older subjects took longer to verify the sentences, especially when the sentences were grammatically complex, but the effect of concurrent memory load on verification latency was the same in both groups. These results cast doubt on the notion that there is an age-related decline in one general pool of processing resources. They also suggest that older people have greater difficulty with the active processing aspects, rather than with the passive holding aspects, of working memory tasks.     

Effects of aging and task difficulty on divided attention performance

We report two experiments that compare the performance of young and older adults on perceptual-motor tasks involving division of attention. Previous studies have shown older people to be especially penalized by divided attention situations, but the generality of this finding was recently challenged by Somberg and Salthouse (1982). The present study was conducted to investigate the possibility that age differences in dual-task performance are amplified by an increase in the difficulty of the constituent tasks, where difficulty was manipulated by varying the central, cognitive nature of the tasks (Experiment 1) or the degree of choice involved (Experiment 2). With the present tasks, strong evidence was found for an age-related decrement in divided attention performance. Contrary to our original expectations, however, it does not seem that division of attention presents some especial difficulty to older people. Rather, division of attention is one of several equivalent ways to increase overall task complexity. In turn, age differences are exaggerated as tasks are made more complex.     

Age-related differences in three tests of visual imagery.

Adult age differences were explored on 3 short tests of the ability to generate and manipulate mental images. Age-related decrements were found in all 3 tests and were especially marked on the Clock Test. The tests are all reliable, as shown by test-retest reliability coefficients. Correlations also revealed that the Brooks Letter Test and the East-West Test appear to tap one common underlying ability, whereas the Clock Test measured a somewhat different ability. The East-West and Clock tests, in particular, may provide rapid and easily administered assessments of age-related changes in aspects of mental imagery.     

Relations between source amnesia and frontal lobe functioning in older adults

A study is reported in which the relations among normal aging, source amnesia, and frontal lobe functioning were explored. Twenty-four older adults (aged 60-84 years) were tested on their ability to remember where they had acquired new factual information; they were also given the Wisconsin Card Sorting Test (WCST), a test of verbal fluency, and other psychometric tests. The degree of source amnesia in this normal sample correlated with age, verbal fluency, and some measures from the WCST. Source amnesia was not related to Performance IQ, however, or to a measure of fact recall. The implications for the relations among aging, memory, and frontal lobe functions are discussed.     

Contemporary Worldviews: Personal and Policy Implications12

In the past several decades, changes in industrial societies have presented a host of issues, worldwide in scope, around which individual attitudes may form: technological growth, population expansion, environmental quality, global resources, differing societal goals, etc. This study (N= 325) was conducted to identify and assess the major attitude/belief constellations surrounding these issues and to examine their psychological basis and implications for risk perception and societal decision-making procedures. Results supported the hypotheses that assessed contemporary worldviews are related in predictable ways to (a) the pexceived risk associated with selected technologies, (b) preferences for the manner in which societal decisions should be made, and (c) a coherent set of psychological variables. Discussion focuses on policy implications of differing contemporary worldviews and on future directions and applications of this line of research.     

The effects of divided attention on encoding and retrieval processes: The resiliency of retrieval processes

We have recently cast doubt (Craik, Govoni, Naveh-Benjamin, & Anderson, 1996; Naveh-Benjamin, Craik, Guez, & Dori, 1998) on the view that encoding and retrieval processes in human memory are similar. Divided attention at encoding was shown to reduce memory performance significantly, whereas divided attention at retrieval affected memory performance only minimally. In this article we examined this asymmetry further by using more difficult retrieval tasks, which require substantial effort. In one experiment, subjects had to encode and retrieve lists of unfamiliar name-nouns combinations attached to people's photographs, and in the other, subjects had to encode words that were either strong or weak associates of the cues presented with them and then to retrieve those words with either intra- or extra-list cues. The results of both experiments showed that unlike division of attention at encoding, which reduces memory performance markedly, division of attention at retrieval has almost no effect on memory performance, but was accompanied by an increase in secondary-task cost. Such findings again illustrated the resiliency of retrieval processes to manipulations involving the withdrawal of attention. We contend that retrieval processes are obligatory or protected, but that they require attentional resources for their execution.     

Lapses of intention and performance variability reveal age-related increases in fluctuations of executive control

We examine the hypothesis that the efficiency of executive control processes is less stable over time in older than younger adults. An age-related decrease in the efficiency of executive control should result in an increase in performance variability in task conditions requiring the recruitment of executive control processes and not in task conditions requiring minimal involvement of executive control. Performance variability was similar for younger and older adults in task conditions requiring minimal executive control and greater for older than younger adults in task conditions requiring executive control. These and other data are consistent with the proposal that aging is associated with a decrease in the stability of executive control over time.     

Levels of processing: past,present. and future?

In this article I first briefly survey some enduring legacies of the Craik and Lockhart (1972) article on levels of processing (LOP) and address some common criticisms. In the next section I discuss whether memory can be regarded as "pure processing", the role of short-term memory in an LOP framework, measurement of "depth" in LOP, encoding-retrieval interactions, the concept of consolidation, and the reality of "levels" of processing. In the final section I offer some speculations on future directions, discussing the notion of levels of representation and a possible continuing role for LOP in memory research.