靶子-靶子任务中认知控制对返回抑制的反转

使用冲突色词作为外源性线索,通过3(任务类型)×2(线索有效性)×2(色词一致性)混合设计考察认知控制对返回抑制(IOR)的影响。结果:(1)线索-靶子任务(CT)和靶子-靶子任务(TT)均产生正值IOR,CT的IOR效应量(32ms)显著大于TT(12ms)。(2)线索有效性和任务类型交互作用显著。按键反应组IOR效应量(11.85ms)显著大于颜色反应组(-18.5ms)和词意反应组(-25.65ms)。证实冲突色词在CT任务中做为线索可产生IOR,这种范式上的新尝试同样适用于TT任务。在TT任务中对认知冲突的觉察和控制导致IOR效应反转,支持注意的非盲性机制。研究为主动操纵被试对线索的认知控制程度,考察复杂任务下实施认知控制对注意定向的影响提供了一条可行途径。

Cognitive Control Reverse Inhibition of Return in Target-Target Task

Inhibition of return (IOR) refers to slowed responses to targets presented at the same location as a preceding stimulus. IOR is typically investigated using a cue-target (CT) task, but the measurement of ‘true’ IOR may be confounded by the effect of non-ocular response inhibition. This confound may be eliminated using a target-target (TT) task, in which responses are made to both stimuli (Coward et al., 2004; Poliakoff et al., 2002). On the other hand, a remarkable feature of the human cognitive system is its ability to configure itself for the performance of specific tasks through appropriate adjustments in perceptual selection, response biasing, and the on-line maintenance of contextual information. The processes behind such adaptability, referred to collectively as cognitive control, have been the focus of a growing research program within cognitive psychology(Botvinick et al., 2001). Inconsistent color words, e.g. the word ‘red’ in green color, are ideal materials to induce cognitive control. Thus, in order to investigate the effects of cognitive control to IOR, we employ the inconsistent color words as exogenous cues in the TT task initiatively. 　　In experiment 1, 20 right-handed participants with a age range from 19-22 years were tested in either the CT task or the TT task randomly. The nature and timing of the stimuli were identical in both tasks, with the two tasks differing only in terms of response instructions. Inhibition of return was obtained in both tasks, but the IOR magnitude was significantly greater in CT (32ms) task than in TT (12ms) task. In experiment 2, 20 participants were all instructed to complete the task of judging the second stimulus (S2), the color of targets, but they were divided into three groups to response to the first stimulus (S1) respectively, which were judging the color of cues, the word of cues or pressing space key when discovering the cues. A repeated ANOVA was applied to the data analysis, and we calculated each group’s IOR effect size by a One-Way ANOVA. Interestingly, we found that IOR magnitude in pressing space key group (11.85ms) was markedly higher than judging the color group (-18.5ms) and the word group (-25.65ms). 　　These results imply that inconsistent color words as exogenous cues are able to achieve typical IOR in CT task effectively. To move forward a step, we demonstrate for the first time that it can extend into the TT task. Moreover, IOR magnitude is significantly smaller in TT task compared to CT task, thereby providing new ideas to explore the effects of cognitive control to inhibition of return. Consistent with our hypothesis, detecting and controlling cognitive conflict lead to the reversal of IOR magnitude. Thus, the reversal of IOR observed in TT task can be attributed to cognitive control, which supporting the unblinded mechanisms of attention. We expect that more behavioral and neurophysiological experiments can refer to this new idea, which would make a greater contribution to exploring the common mechanism of attention.