Age Differences Of Conflict Adaptation Effects Under Different Tasks

When confronting the conflict environment, people could flexibly adjust their executive control ability to resolve the current conflict effectively. An increasing number of studies show that the degree of cognitive control over information processing may be timely varied on the basis of information from mechanisms dedicated to the online monitoring of performance. The studies of cognitive control are mostly focused on the conflict adaptation effect. This effect is that reaction times (RTs) on congruent trials preceded by congruent trials (cC) are faster than those on congruent trials preceded by incongruent trials (iC). Similarly, RTs on incongruent trials are faster after incongruent trials (iI) than after congruent trials (cl). That is, the detection of conflict on previous trial acts as a signal to increase cognitive control, there improving the performance of the upcoming conflict. The process of conflict adaptation mainly involves the frontal region, which engages conflict detection and control.Previous researches have indicated that aging contributed to some structural and functional brain changes, which shows that age-related inhibitory deficits reduced older adults’capacity to resolve conflicts between competitive information and older adults performed poorer than young adults. The appearance of conflict adaptation reflects not only the ability of conflict monitoring, but also the ability to modulate top-down cognitive control based on conflict situations. This paper are designed to investigate: firstly, whether older people show the significant conflict adaptation; Secondly, the effects that aging has on the conflict adaptation; Lastly, how will the conflict adaptation vary with the cognitive aging by comparing tasks with different difficult levels.This study, beginning with individual’s behavior, uses two experiments controlled strictly. Experiment1uses the classical Flanker task which contains a single cognitive conflict and taking28healthy college students and30healthy older adults to explore whether the conflict adaptation are existed in both of young adults and older adults. Experiment2incorporates Simon and Flanker conflict and has27college students and25older adults been participated. Experiment2aims to discuss whether there are differences of conflict adaptation between young adults and older adults after increasing the difficulty of task and the level of conflict.The results shows:in the classical Flanker task, older adults show the similar ability of conflict adaptation with young adults. In the multiple conflicts task, however, young adults still show strong conflict adaptation effect, the old adults do not significantly show conflict adaptation effect.We conclude following several conclusions based upon the results above:First, aging affects the reaction speed and interference effects of conflict tasks:the old adults response more slowly than young adults in both tasks and have greater interference effects, which suggest that older adults are easier affected by the interference information and unrelated responses than young adults and they have deficits in the ability of inhibitory.Second, the congruence of previous trials affects the reaction speed of current trials: both of the two experiments have shown the conflict adaptation effect, which suggests the previous conflict experience does will facilitate the resolution in the following conflict. People could adjust the cognitive control based on the current conflict levels.Last, aging has an effect on the adjustment of cognitive control after a conflict:in the single conflict Flanker task, the conflict adaptation effect is manifested in young adults group and older adults group and has no differences between them while the conflict adaptation effect exists significantly in the young adults but the older adults in the multiple conflicts integrated task, which suggest that older adults have different performance from young people in conflict adaptation effect under varied difficult tasks. This may indicate that the old adults could recruit equivalent cognitive resources to overcome the deficits of inhibited ability through the compensatory activity in the low difficult tasks. And they can adjust cognitive control of the current trial based on the conflict experience of the preceding trial. However, when the conflict and difficulty increases, older adults could not recruit more cognitive resources required by cognitive control and the ability of conflict adjustment would exceed the maximum potential of the compensatory activity, then the old adults could not show the effective trial-to-trial modulations as well as the young adults.