On age differences in processing variability and scanning speed
Article Abstract:
Research indicates that ''internal noise'' may be responsible for the age differences found in performance on many memory and perceptual tasks. The internal noise hypothesis proposes that older adults have a loss of processing resolution whereby target stimuli (the items to be remembered) are not as easily distinguished from background, or nontarget stimuli. When we view a list, for instance, the order of the list is stored in memory. But as we age, according to internal noise hypothesis, it is probable that the positions of individual items on the list will drift, or background items will be recalled instead. The theory also holds that as a function of where the item was originally stored in memory, an item's familiarity decreases the further away it gets from where its original position. In the present investigation, two experiments were performed to examine adult age differences on a recognition memory task for item order. In experiment one, which tested processing variability, subjects saw four letters and they were asked if a subsequent probe letter was in its original position or in another position relative to the other letters. They were tested both immediately and after a 10-second distractor task. Experiment two was virtually the same, except acoustic memory was tested and there was no distractor task. The internal noise hypothesis predicted that there should be distance effects, as described above, in both tasks resulting in more errors in recognition when letters were transposed. The data supported this hypothesis, as older adults exhibited higher levels of processing variability. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journals of Gerontology
Subject: Seniors
ISSN: 0022-1422
Year: 1991
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Adult age differences in the rate of information extraction during visual search
Article Abstract:
Accuracy is related to speed in the visual search and classification of materials, and it is thought to vary as a function of age. In general, accuracy increases with increased reaction time (RT, the time a subject takes to respond to a task), although age may play into this relationship as well. Two groups of subjects were tested in the present study. Group one consisted of 24 adults with an average age of 20 years, and group two consisted of 24 adults with an average age of 66 years. Subjects were shown four letters on a computer screen and were required to identify the target letter (target letters had been identified earlier) and to press the appropriate button corresponding to it. The length of the display, and therefore RT, was controlled by the computer. Age-related slowing was seen with respect to the speed with which subjects were able to extract the target letter and press the appropriate button. As RT was increased, younger subjects benefited more than older subjects did. It was also found, however, that older subjects preferred to be more sure of their answers than younger subjects, resulting in a slower response time. When this was controlled for in the analysis of the data, however, the difference in RTs between younger and older subjects remained significant. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journals of Gerontology
Subject: Seniors
ISSN: 0022-1422
Year: 1991
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Influence of response selection and noise similarity on age differences in the redundancy gain
Article Abstract:
The effects of different response selection loads, two-choice or go/no-go, and different levels of distraction, one or more noise letters, on visual search tasks were tested for younger and older adults. On non-noise (target-only or TO) trials, both groups exhibited a clear redundancy gain, with older adults exhibiting a larger gain. Response selection load and age did not show interaction. On noise load trials, older subjects showed more redundancy gain for target-plus-noise trials than for TO trials. These results suggest that older adults have less weaker processing and selective attention abilities.
Publication Name: Journals of Gerontology
Subject: Seniors
ISSN: 0022-1422
Year: 1993
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