Post-error behavioral adjustments under reactive control among older adults.

This study analyzed the effects of aging on post-error behavioral adjustments from the perspective of cognitive control. A modified error awareness task was administered to young (n = 50) and older (n = 50) adults. In this task, two buttons were placed on the left and right sides in front of the participants, who were instructed to use the right button to perform a go/no-go task, and were notified if they made an error. There were three experimental conditions (A, B, and C): participants had to push the right button once in Condition A and twice in Condition B and C when a go-stimulus was presented. Conversely, participants were asked to withhold their response when a no-go stimulus was presented. Response inhibition differed depending on the experimental condition. The participants were asked to push the left button as quickly as possible when an error occurred. The results showed relatively longer reaction times to sudden errors among older adults compared with young adults. Furthermore, the difference in the error responses (i.e., accidentally pushing the right button once or twice when a no-go stimulus was presented) strongly influenced older adults' response time after an error. These results suggest that the shift from proactive to reactive control may significantly influence post-error behavioral adjustments in older adults.

[Do practices of learning activities improve the cognitive functioning of healthy elderly adults? From the viewpoint of a transfer effect].

The present study examined influences of reading aloud and performing simple calculation on the cognitive functioning of healthy elderly adults, based on the findings that these tasks activated the prefrontal lobe. The elderly adults' memory and inhibitory functions were assesed by Short-Term memory, CST, Stroop, and SRC tasks, before and after intervention for 18 months. The study found that the learning group had significant improvement from the pre- to the post-test for the short-term memory, STM, CST, and Stroop tasks. On the other hand, there was significant decline over the 18 months in the control group which was given only the assessment tasks. These results are discussed in terms of the effectiveness of cognitive training.

Motor inhibition in aging: impacts of response type and auditory stimulus.

The authors examined the effects of response types and the presentation of auditory stimulus on motor inhibition. Continuous responding tasks were conducted with 27 younger adults and 39 older adults. The results indicated the following: (a) response type significantly affected error rates in older adults, (b) the presentation of an auditory stimulus facilitated responses and decreased reaction times in both younger and older adults, (c) the presentation of an auditory stimulus also increased error rates in older adults, and (d) the effect of response type on error rate remained in experiments conducted under different conditions in older adults. This suggests that in older adults, movement and the associated nervous excitation have significant effects on motor inhibition.

Inhibition of return using location discrimination in two age groups.

The present study investigated "inhibition of return" which refers to increased response latency when the target in a location discrimination task appears in the same location on consecutive trials. Research to date has suggested that this effect is little changed across age. However, this study, which compared 12 older adults in good health (M=73.0, SD=5.3) with younger adults using the target-target paradigm to examine inhibition of return, suggests there is a strong and continuous effect in older adults in comparison to younger adults. Results indicate the possibility that the inhibitory function may become stronger at an older age.

Inhibitory function in the stimulus-response compatibility task.

Changes of a location-based inhibitory function were investigated by performing a Stimulus-Response Compatibility task under two conditions. This task allows study of the efficiency of the inhibitory function by analyzing differences in error rates and in response time under various conditions of stimulus and response compatibility. In Exp. 1, with 28 college students, the effect of a dual task on the Stimulus-Response Compatibility effect was examined. In a dual-task, a predetermined stimulus such as a color is identified and the number of times a color is displayed is counted. In this experiment, under a dual task using visual stimuli, a decline in error responses and reduction of the Stimulus-Response Compatibility effect were observed. In Exp. 2, 29 college students participated in an identical experiment with the exception that an auditory stimulus was presented as the dual task. Similar to Exp. 1, there was a significant reduction in the number of error responses in the dual-task condition. Conversely, there was no significant change in Stimulus-Response Compatibility effect as estimated by response time. These results suggest that the two visual pathways as proposed by Goodale (1995) and the evocation of intentional attention may affect the Stimulus-Response Compatibility effect.

Inhibition of return using discrimination of location.

The present study investigated "inhibition of return" which refers to increased response latency when the target in a location discrimination task appears in the same location on consecutive trials. Location discrimination tasks were performed by 28 university students (19-21 years of age) in two experiments. In Exp. 1 the task was to press a left or right button in response to a stimulus displayed on a computer screen. The first condition manipulated stimulus-response compatibility which resulted in changing the inhibition of return. Inhibition of return was stronger when the condition was stimulus-response incompatibility. This result shows that inhibition of return functions strongly under incompatible conditions. A second condition required performance of dual tasks in Exp. 2. Again, changes in inhibition of return were seen. These results show that inhibition of return functions strongly under both dual task and incompatible conditions. Inhibition of return was interpreted as functioning strongly when the task was more difficult.