有很多研究都認為注意力機轉存在於兩個獨立的抑制系統中，一是對干擾物本體 的壓抑，一是對干擾物所在位置的抑制，並認為老年人注意力衰退，是因為對干擾物本體的 壓制能力受損的緣故。本論文以兩個實驗來說明過去的實驗結果所看到的干擾物本體壓抑效 果，是因為沒有去除位置抑制作用，干擾物重複出現在相同位置，所引發的位置抑制的假象 。在去除位置重複的因素以後，注意力對干擾物本體的真正作用是一個正向的促發作用。實 驗一以老年人和年輕人為受試者，兩者在干擾物本體單獨重複時，都出現正向的促發作用； 只有在位置與本體都重複時，才出現一般研究所報告的年輕人為負向抑制，而老年人沒有效 應的現象。實驗二改變目標物與干擾物的呈現位置距離、並以年輕人為受試者，實驗結果清 楚地看到當沒有將位置與本體分離時，其效果量是單獨的位置抑制與本體促進兩者的加成。 在最小刺激距離時，由於本體促進效果最大，與位置抑制的加成後，就不再有負向的促發效 果，使得年輕人也產生和一般所誤認的本體壓抑效果受損的假象。這些結果與過去有關負向 抑制效果的理論預測有很大的不同，論文最後並就相關理論作討論。

　　　　　It has been argued that during selection of target objects, both irrelevant distractor identities and their locations are inhibited. While checking into previous studies, we found there was a confounding of item repetition and location repetition, most studies repeated the distractor item on the same location as at the probe display. Such operations might underestimate the possibility that irrelevant distractor items are facilitated, but not inhibited due to merging the effects of the location inhibition and the identity facilitation. Two Experiments examined whether the priming effects of distractor identities are positive or negative by using unrepeated stimulus and putting the distractor on a different location, instead of the same location, from the prime display to the probe display. Results of experiment 1 showed the positive priming of identity and the negative priming of location for both young and old subjects, but only young subjects showed significant negative priming effect when both location and identity were repeated. In the experiment 2, the distance between target and distractor were manipulated for the purpose of getting different amount of identity facilitation and location inhibition. When the target and the distractor were at a shorter distance on double repetition condition (repeated both location and identity of distractors), even young subjects did not show significant negative priming effect. These two studies suggested the positive priming of distractor identity, and the negative priming of distractor location. The results of these two experiments were discussed in terms of the recent theoretical hypothesis of negative priming.