Matching- and delayed matching-to-sample performance as measures of visual processing, selective attention, and...

Visual processing time, selective attention to visual cues, and memory for those cues were measured in groups of normal and alcoholic research participants within three different age ranges: young (35-45 yr), middle (46-59 yr) and older (60-70 yr). Performance across groups also was compared to that of alcoholic Korsakoff patients, known to have processing and attentional abnormalities. The matching-to-sample task was employed in which participants are required to match one of two laterally located response choices with a stimulus displayed in the center between them. Duration of the center sample stimulus varied between 20 and 500 msec, and delay between sample offset and response-choice (match) onset varied between 0 and 30 sec. Complexity of the sample stimulus also was varied, containing one or two dimensions (color and/or form). Levels of performance for all groups improved with increased sample stimulus durations, and were negatively related to a stimulus complexity and length of delay. Significant group differences in accuracy were evident with short stimulus exposures; the Korsakoff and older groups made more errors than the younger groups. Similarly, response times were influenced differentially by stimulus duration, stimulus complexity, and the delay between sample and matching stimuli, with young participants (alcoholics and controls) responding fastest. Results emphasize the contribution of processing deficits to other cognitive impairments in aging and alcoholic individuals, as well as the relative independence of aging and alcoholism.