探討知覺負荷量對於干擾圖臉處理的影響

The Effect of Perceptual Load on the Processing of a Distracting Schematic Face

人臉是一種特別的視覺刺激，在視覺處理上會優先被處理，此論點已獲得許多研究證實，人臉作為一個干擾刺激時，會被自動地處理，影響目標作業的反應選擇。然而，Bindemann、Burton及Jenkins（2005）卻發現，當目標刺激為人臉時，干擾人臉不會被處理，且不會影響目標作業的判斷。基於以上結果的不一致性，本研究欲釐清：當參與者在搜尋目標人臉時，是否仍會受到旁側突顯干擾人臉的影響（由相容效果來反映），且如此的影響是否受到目標作業的知覺負荷量調節。參與者被要求在環形排列的刺激中，尋找目標人臉，判斷其情緒性（實驗一、二及四）或身份（實驗三），同時忽略旁側的突顯干擾圖臉。藉由操弄目標與干擾圖臉的反應相容性，來測試干擾圖臉是否有被處理。實驗結果發現，當非目標刺激為五個相同的圓盤（實驗一與二）與中性圖臉（實驗一與三）時，可以觀察到相容效果（亦即在目標與干擾刺激相同時，正確率較不相同時來的高，或反應時間較快）；而在非目標刺激為彼此相異的正立（實驗二、三或四）或倒立（實驗四）圖臉時，相容效果則消失。這些結果可以被知覺負荷量理論解釋，同時也可以利用注意力視窗假說來解釋，干擾人臉是否會被處理，影響目標作業的判斷，取決於當時目標作業的知覺負荷量。

Faces are special as they can be processed with higher priority compared to the non-face objects. Even when faces are presented as distractors, they are automatically processed to influence response selection. However, an earlier study (Bindemann, Burton, & Jenkins, 2005) showed that a distracting face was not processed to influence response selection when a face categorization task was performed. To solve this contradiction, this study investigated whether a salient distracting face is processed when participants were required to search for a face among five non-targets and judge its emotionality (Experiments 1, 2, and 4) or identity (Experiment 3). Response compatibility between target and distractor faces was manipulated to examine whether the distractor is processed. Results showed that when non-targets were five identical yellow circles (Experiments 1 and 2) and neutral faces (Experiments 1 and 3), the compatibility effect was observed (higher accuracy or faster response time in the compatible condition than in the incompatible condition); in contrast, when the non-target faces were upright (Experiments 2, 3, and 4) and inverted heterogeneous faces (Experiment 4), the compatibility effect was eliminated. These results suggested that perceptual load can modulate the processing of a distracting face. In a low-load condition, the distracting face is processed, while in a high-load condition the distracting face is not processed to influence response selection. The results are consistent with the proposals from both perceptual load theory and the attentional window perspective.