注意力焦點的大小及其在視覺空間中之移動

The Size of Attentional Focus and Attentional Movement in the Visual Space

我們利用中央導引的方式於三個實驗中變化目標刺激的大小及導引線索與目標的刺激間距以檢驗注意力焦點的大小與其移動速度之間的關係。實驗一的結果顯示注意力移動的快慢並不受其移動距離的影響，意謂著注意力是以等時的方式移動。這項發現在實驗二中再度得到支持；此外並且發現注意力焦點的大小似乎會影響注意力移動的速度──注意力的焦點愈大，其在視覺空間中移動的速度愈快。這些發現似乎建議注意力的焦點首先放大至含括目標即將出現的位置，然後於目標出現時再根據刺激的大小縮小至一適當的範圍。此一對伸縮鏡頭模式（Eriksen & Yeh, 1985）略作修正的看法在實驗三中得到支持──結果顯示當注意力最初處於廣為分佈的狀態時，目標刺激愈小，注意力所需要調整的時間就愈長，反之亦然。中央及週邊導引為不同機制所致的可能性亦在文中加以討論。

In three experiments we examined the relationship between the size of attentional focus and the speed of its movement by varying the size of a target stimulus and and by varying the interstimulus interval between an orienting cue and the target in a central-cuing paradigm. The result of Experiment l showed that the speed of attentional movement was unaffected by the distance it had to traverse, suggesting that attentional movement is time-invariant with respect to its traveling distance. This finding was replicated in Experiment 2; moreover, it was found that the size of attentional focus appears to affect the speed of attentional movement in that the larger the attentional focus is, the faster it would move in the visual space. These findings seem to suggest that the focus of attention was first expanded to enclose the location for a forthcoming target and was then contracted to an extent calibrated in accordance with the size of the target. Such a modified view of the zoom-lens model (Eriksen & Yeh, 1985) received some support in Experiment 3, the result of which showed that when attention was initially broadly distributed, the smaller the target was, the longer it took for attention to be properly calibrated, and vice versa. The possibility that different mechanisms may underlie central versus peripheral cuing was also discussed.