Mattler Uwe
Department of Neurology II, Center for Advanced Imaging, Otto-von-Guericke Universität, Magdeburg, Germany.
Q J Exp Psychol (Hove). 2006 Oct;59(10):1745-63. doi: 10.1080/17470210500344494.
When participants must respond to a relevant central target and ignore irrelevant flanking stimuli the flanking stimuli produce a compatibility effect, with increased response speed and accuracy on compatible as compared to incompatible trials. This flanker effect is larger when compatible trials are more frequent than incompatible trials (the ratio effect). A potential explanation of this ratio effect is that the occurrence of frequent incompatible trials causes the focus of spatial attention to be set narrower than when there are frequent compatible trials. The present investigation tests this hypothesis by comparing the flanker effect with near and far flankers. The hypothesis predicts that the flanker distance should modulate the ratio effect more when incompatible trials are frequent than when compatible trials are frequent. The results, however, show the opposite pattern: Distance effects are larger in conditions with frequent compatible trials. Moreover, the effect of distance but not the ratio effect was eliminated when flanker distance remained fixed across blocks of trials, and also when participants had to attend to flanker stimuli in a go-no-go task. These results suggest that the ratio effect does not result from an adjustment of the focus of spatial attention.
当参与者必须对相关的中央目标做出反应并忽略无关的侧翼刺激时，侧翼刺激会产生一种兼容性效应，与不兼容试验相比，兼容试验的反应速度和准确性会提高。当兼容试验比不兼容试验更频繁时（比率效应），这种侧翼效应会更大。对这种比率效应的一种潜在解释是，频繁出现的不兼容试验会使空间注意力的焦点设置得比频繁出现兼容试验时更窄。本研究通过比较近侧翼和远侧翼的侧翼效应来检验这一假设。该假设预测，当不兼容试验频繁时，侧翼距离对比率效应的调节作用应比兼容试验频繁时更大。然而，结果显示出相反的模式：在兼容试验频繁的条件下，距离效应更大。此外，当侧翼距离在各试验块中保持固定时，以及当参与者在一个“是-否”任务中必须关注侧翼刺激时，距离效应而非比率效应被消除。这些结果表明，比率效应并非源于空间注意力焦点的调整。
