物體特徵在位置負向促發所扮演的角色

Abstract

本研究探討靜態物體的非空間特徵屬性（顏色與本體）在位置負向促發裡扮演的角色。實驗一以少量的刺激重複呈現來增加刺激的激發量，提高干擾刺激的競爭力。結果顯示位置的正向以及負向促發效果。實驗二中，大量刺激作為材料使刺激的激發量低，降低干擾刺激的競爭力。結果顯示有位置正向但沒有負向促發效果。實驗三採用少量不同刺激，但偵測嘗試的刺激顏色與其促發嘗試的刺激顏色無關，結果顯示只有位置負向促發效果。綜合三個實驗結果顯示，本體與空間的處理可以是獨立的，本體的激發量會影響物體整體激發量。只有整體激發量高時，抑制機制才會啟動，並選擇性地作用於與作業相關的位置屬性，而非抑制物體的所有屬性。此外，當顏色與目標及干擾刺激無特定關連性，且偵測嘗試與促發嘗試裡的刺激顏色無對應關係時，只需要位置表徵的重複即可展現位置負向促發效果。物體的非空間特徵屬性在選擇處理的不同階段，影響位置的定位、選擇、及抑制，但不會影響其提取。

Using static displays, we investigated the role of non-spatial features in the location negative priming effect. Participants responded to the location of a pre-defined color while ignoring a distractor on screen. Identity was irrelevant to the task. A small set of stimuli was presented repetitively in Experiment 1 so that the activation of each stimulus identity was high and competition from the distractor was strong. Location positive and negative priming effects were observed. A large set of non-repeated stimuli was used in Experiment 2 to reduce the competition imposed by the distractor. Location negative priming was not found, although positive priming was still observed. Experiment 3 used a small set of repeated stimuli, but the target and the distractor colors were randomly defined in each trial while the stimulus colors in the probe trials were unrelated to those of the prime stimuli. Negative location effects were observed, but identity priming effects were not observed. The results showed that identity and location are processed independently. Strong competition based on the whole object including the task-irrelevant identity feature is important to activate the inhibitory mechanisms. Once instigated, inhibition operated selectively on the goal-relevant feature of location. Color, the task-defining feature for selection, influences how location is processed but is inessential in triggering the retrieval of location information.