注视-西蒙效应的空间编码机制

采用注视-西蒙范式探讨了注视方向知觉的空间编码机制。实验一让被试采用双手交叉的反应方式，发现注视-西蒙效应并不随反应手的交叉而反转，说明它涉及抽象的空间方向编码，而非基于以手为参照系的半侧优势效应。实验二采用纯音音调辨别任务，发现了典型的注视-西蒙效应，结合实验一视觉通道的结果，说明注视-西蒙效应并非特异于视觉通道，它可能发生在晚期的反应选择阶段，而非早期的知觉阶段。结果支持注视线索能够自动诱发观察者形成抽象的方向表征的观点。

The Spatial Coding Mechanisms of the Gaze-Direction Simon Effect

As the gaze-direction Simon effect(gaze Simon effect,GSE) shows,although completely irrelevant to the task,the direction of the gaze has an influence on reaction times in a two-choice spatial discrimination task based on the color of eyes.In fact,there were controversies on this topic.Many researchers tried to interpret the processing mechanism of GSE.Zorzi et al.(2003) assumed that a spatial code of perceived gaze direction was fast and automatically extracted in order to influence RT in the color discrimination task.However,numerous studies showed that observing averted gaze could also elicited spontaneous saccades in the direction of the gaze cue.Ricciardelli et al.(2002) claimed that perception of the gaze direction might act as a powerful trigger for involuntary imitation.Moreover,Frischen et al.(2007) held that observing others’ gaze shifts evoked a similar motor program(saccade preparation) in the observer.Such simulated or "mirrored" activation of motor programs by the mere observation of actions could explain the gaze cueing effect.In other words,observing gaze evokes a tendency to execute saccades in the corresponding direction,imitating the observed behavior.Thus,it remains unclear whether an Abstract spatial coding is necessary for GSE.Two experiments were performed to investigate the spatial coding mechanisms of the gaze Simon effect.In the first experiment,twelve subjects were presented with a gaze cue to the central visual field,and were asked to perform a color judgment Simon task with their hands crossed.In the second experiment,another twelve subjects were presented with a gaze cue and a pure tone and were instructed to discriminate the pure tone(high or low).In both experiments,there were three conditions:(1) in the gaze-direction corresponding condition,the gaze direction and the response side corresponded(i.e.,both were left or both were right);(2) in the gaze-direction non-corresponding condition,the gaze direction and the response side did not correspond(i.e.,the gaze direction was to the left and a right response was required);(3) in the gaze-direction neutral condition,the gaze direction was direct to the observer.All subjects were told that the gaze cue was irrelevant to the task and could be ignored.The result showed that there was no reversal of the direction of the GSE in the first experiment,thereby suggesting that the GSE operates at a more Abstract level of representation of the left and right responses,rather than a hemispheric dominance effect on the basis of a hand-centered frame reference.Furthermore,a regular GSE was found in the second experiment.Combined with the results of two experiments,we believed that GSE did not occurs at the earlier perceptual processing stage.Thus,it could be speculated that the GSE occur at the response selection stage.The current results provide direct evidence to support the idea that gaze direction can automatically generate a spatially Abstract code.The GSE did not result from imitating the observed behavior.