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.     

A reanalysis of the influence of a "friendly visitor" program

A paper in the American Journal of Community Psychology (AJCP), by Reinke, Holmes, and myself, reported the results of a study of the influence of a friendly visitor program on the cognitive functioning and morale of elderly individuals. The program was reported to have had a significant multivariate effect on a combination of cognitive and morale measures and significant univariate effects on memory, self-perceived health, and activity director's ratings. Being intrigued by the memory finding, I conducted a follow-up study to further investigate the effect of a visitation program on cognitive functioning. In this second study the dependent measures included all of the cognitive variables included in the original study as well as some additional memory variables. The visitation program in the follow-up study had no effect on any of these measures. As a result of my failure to obtain a significant memory effect such as that reported in Reinke et al. (1981), I reanalyzed the data from the original study. In my reanalysis, the only significant effect was a borderline univariate effect for self-perceived health; the multivariate effect did not approach significance. On the basis of my inability to produce the results reported in Reinke et al. when I reanalyzed the original data, I must conclude that the friendly visitor program did not have the effects attributed to it in the original report.     

The precaution adoption process

This article presents a critique of current models of preventive behavior. It discusses a variety of factors that are usually overlooked-including the appearance of costs and benefits over time, the role of cues to action, the problem of competing life demands, and the ways that actual decision behavior differs from the rational ideal implicit in expectancy-value and utility theories. Such considerations suggest that the adoption of new precautions should be viewed as a dynamic process with many determinants. The framework of a model that is able to accommodate these additional factors is described. This alternative model portrays the precaution adoption process as an orderly sequence of qualitatively different cognitive stages. Data illustrating a few of the suggestions made in the article are presented, and implications for prevention programs are discussed.     

Does nondirectional signalization of target distance contribute to navigation in the Morris water maze?

The possibility that rats can navigate in the Morris water maze by reducing the difference between the memorized platform scene and the current sensory input was tested in nine blind rats. A computerized videosystem monitored the rats' movements in the pool and converted the rat-target distance into tones the frequency of which increased in 64 equal steps from 120 Hz at 128 cm to 7680 Hz at 0 cm. During 15 days of training to find a fixed platform position from different starting points (12 trials per day) average escape latencies decreased from 39.0 to 25.4 s. The performance significantly deteriorated when the acoustic distance signalization was omitted and/or when the target position was changed form trial to trial. It is concluded that blind rats solved the task by simultaneously employing search strategy based on position responses, mapping using acoustic background beacons, and distance reduction navigation. It is argued that the various strategies are additive and that their relative significance depends of the conditions of the experiment.     

Pure agraphia and Gerstmann's syndrome as a visuospatial-language dissociation: an experimental case study

A right-handed man suffered a left parieto-occipital cerebral infarction, causing agraphia with Gerstmann's syndrome but without major aphasia, alexia, or apraxia. Oral spelling was superior to written spelling. Experiments were performed involving (1) analysis of errors in writing, (2) tasks of visual imagery, and (3) identifying letters drawn without leaving a visual trace. The results suggest that the agraphia and Gerstmann's syndrome are due to a dissociation of language skills and visuospatial skills caused by a dominant parieto-occipital lesion.