以重疊物體探討物體為基礎的回向抑制及其產生要件

Object-based Inhibition of Return: Evidence from Overlapping Objects

回向抑制（Inhibition of return, IOR）指的是︰對於出現在剛被提示過的位置或物體上的目標物，反應時間會增加。過去顯示回向抑制也能以物體為基礎的研究皆使用空間上分開的物體作為刺激，因而留下一個重要而未解決的問題：「物體為基礎的回向抑制是否需仰賴物體間不同的二度空間表徵才得以展現？」。我們使用物體提示派典（object cuing paradigm）和可排除空間表徵混淆變項的設計來探討這個問題。兩個三角形重疊於畫面中，其中一個三角形會先亮一下，接著目標物出現在任一三角形的任一端點，觀察者必須判斷目標物是變亮或變暗。實驗結果發現，當線索到目標物的時距夠長以及有注意力攫取物的情況下，以物體為基礎的回向抑制現象得以在二度空間重疊的物體上展現。

Inhibition of return (IOR) refers to the delayed response to a location or an object that has recently been cued. Previous studies showing object-based IOR in either dynamic or static displays have used spatially separate stimuli that unavoidably involved spatial representation. I t thus remains unclear whether the object-based IOR is a special case limited to the condition in which objects are separated in a 2-dimensional space. To rule out confounding with locationbased IOR, we used two overlapping triangles constituting a "Star of David" in this study to examine whether and under what conditions object-based IOR can be observed. An object cuing paradigm was used in which one of the two triangles was brightened as the cued object. The target was a luminance change in one of the three disks connected to the vertexes of the cued or the uncued triangle. The participants judged whether the target brightened or dimmed. Results show that object-based IOR can occur for spatially overlapping object under two necessary conditions: A long enough cue-to-target SOA and the existence of an attractor that is presented after the cue and before the target.