Fondazione Santa Lucia IRCCS, Roma, Italy.
Neuropsychologia. 2010 Mar;48(4):1011-5. doi: 10.1016/j.neuropsychologia.2009.11.025. Epub 2009 Dec 2.
The "Simon effect" is the performance advantage for spatially corresponding target-response ensembles that is observed when coding of target position is irrelevant for the selection of motor responses. The "attentional-shift" account of the Simon effect holds that it arises from the congruency between response location and the direction of the last shift of attention toward the target. The "referential-coding" account traces the origin of the Simon effect back to the congruency between the response location and the position of the target with respect to a spatial reference frame. We were able to contrast these two hypotheses using full-field horizontal optokinetic stimulation (OKS). It was shown that OKS moving in one horizontal direction drives covert orienting of attention toward the side of arrival of OKS, i.e. the "In-coming" side, which is opposed to the direction of OKS motion toward the "Out-going" side (Teramoto et al., 2004; Watanabe, 2001). We therefore asked healthy participants to discriminate between slow and fast velocities of leftward or rightward OKS. "Fast" and "slow" responses were associated to response buttons positioned in the left or right side of space. The "attentional-shift" account of the Simon effect predicts that response compatibility should be related to the direction of the attentional shift induced by OKS, i.e. in the direction opposite to OKS motion. By contrast, the "referential-coding" hypothesis predicts that response compatibility should be related to the direction of OKS displacement with respect to its starting position. We observed faster RTs when the response button was on the "In-coming" side of space, opposite to the direction of OKS motion. This result supports priority of attentional over referential-coding factors in the genesis of the Simon effect.
“Simon 效应”是指在目标位置的编码与运动反应的选择无关时，空间对应的目标-反应组合的表现优势。“注意力转移”解释 Simon 效应认为，它源于反应位置与注意力最后一次转移到目标的方向之间的一致性。“参照编码”解释将 Simon 效应的起源追溯到反应位置与目标相对于空间参照系的位置之间的一致性。我们能够使用全视野水平视动刺激 (OKS) 来对比这两种假设。结果表明，一种水平方向的 OKS 运动驱使注意力朝着 OKS 到达的一侧，即“传入”侧，进行隐蔽的定向，这与 OKS 朝着“传出”侧运动的方向相反（Teramoto 等人，2004 年；Watanabe，2001 年）。因此，我们要求健康参与者区分左右 OKS 的慢和快速度。“快”和“慢”反应与空间左或右侧的反应按钮相关联。“注意力转移”解释 Simon 效应的预测是，反应兼容性应该与 OKS 引起的注意力转移的方向有关，即与 OKS 运动的方向相反。相比之下，“参照编码”假说预测反应兼容性应该与 OKS 相对于其起始位置的位移方向有关。当反应按钮位于与 OKS 运动方向相反的“传入”侧空间时，我们观察到更快的 RT。这一结果支持了在 Simon 效应的起源中，注意力优先于参照编码因素的观点。
