The Impact Of Reward And Conflict Expectation On Cognitive Control

People often use cognitive control to complete the task goal when they need to control the irrelevant information and make the right behavioral response.There are a lot of theories about cognitive control.The Dual Mechanisms of Cognitive Control Account proposed by Braver et al in 2007 provides a new perspective,which suggests that cognitive control consists of proactive control and reactive control.These two cognitive control have different characteristics,and there is a tradeoff between these two kinds of control to optimize task performance.Previous studies had shown that reward could modulate human behavior and lead to proactive control.But most of them were about supraliminal reward.The study on subliminal reward were rarely,especially the relationship between subliminal reward and cognitive control.Conflict expectation is also an important factor that affects cognitive control.When there is a high proportion of congruent trial(conflict expectation),participants tend to improve the level of proactive control to deal with the conflict.Stroop task is an important paradigm to study cognitive control,and Stroop effects is often used to reflect the overall level of cognitive control.The size of the Stroop effect is related to proactive control or reactive control,while the conflict adaptation effect is only considered to reflect the reactive control.In the case of strengthening the proactive control,whether the conflict adaptation effect(reactive control)will be changed? The question remains unknown.In addition,previous research often investigate only single factor's influence on cognitive control,the interaction of these factors during conflict processing also unclear.On the basis of previous studies,this study attempts to investigate and answer these questions.In two experiments of this study,participants performed a variant of the Stroop task,receiving performance dependent monetary rewards in some blocks.In experiment 1,we used three kinds of colors and color words as stimulus materials,selected Stroop effect and the conflict adaptation effect as the indicator of cognitive control,with the aim to explore the following two questions:(1)Does the reactive control will be change in the case of improveproactive control ?(2)Does subliminal reward enhance cognitive control and influence Stroop effect? The results revealed that:(1)In the condition of supraliminal and subliminal reward,the conflict adaptation effect(reactive control)of error rate was significantly lower than that of non reward;(2)In the condition of supraliminal reward,the Stroop effect of reaction time and error rate were all significantly lower than that of no reward,and in the condition of subliminal reward,only the Stroop effect of error rate was significantly lower than that of no reward.In experiment 2,we used four kinds of colors and color words as stimulus materials divided them into two subsets,used Stroop effect as the indicator of cognitive control,with the aim to explore the another two questions:(1)The interaction of reward and conflict expectation on cognitive control;(2)Whether the influence of subliminal reward and conflict expectation on cognitive control is different from that of subliminal reward and conflict expectation.The data revealed the Stroop effect to be reduced in high expectancy compared to low-expectancy blocks only under conditions of low,but not high motivation;In addition,we found that high motivation reduced the congruency effect relative to low motivation only when conflict expectancy was low,not when conflict expectancy was high.Combining the results of Experiment 1 and experiment 2,the main conclusions of this study were as follows:(1)In the case of improved proactive control by reward,error rate's conflict adaption effect was reduced,which means reactive control was affected;(2)There was a significant interaction between reward and conflict expectation: Reward(or conflict expectation)cannot further enhance the proactive control under the conditions of high conflict expectation(or reward);(3)The influence of subliminal reward and conflict expectation on cognitive control was as same as the influence of subliminal reward and conflict expectation;(4)On the whole,both subliminal reward and subliminal reward can enhance the individual's cognitive control,but the effect of subliminal reward on cognitive control is not as good as that of subliminal reward.