亮度梯度線段之運動錯覺探討：
亮度與對比之注意力攫取

典型的線段運動錯覺是在一條水平線段出現前先在其端點位置出現一個線索，則對其會產生由線索位置往另一端延展出現的運動錯覺。Von Grünau、Saikali及Faubert（1995）曾利用亮度梯度線段檢驗線段運動錯覺的成因，結果發現當注意力不均勻地分布在空間中時會影響對後續呈現刺激的知覺。Von Grünau等人相信亮度梯度線段中亮度較高的一端能有效地攫取注意力並誘發線段運動錯覺。然而，後續的研究者對線段運動錯覺可能受到的干擾因素進行探討時發現：反應按鍵選擇、受試者是否知曉實驗目的等因素都可能會介入影響線段運動錯覺。這些干擾因素在Von Grünau等人的實驗中並未做控制。因此，本研究的目的即在控制這些干擾因素後，重新檢驗亮度及對比特徵影響注意力後對線段運動錯覺產生的影響。結果發現反應按鍵選擇並不會影響線段運動錯覺，而注意力設定則會對線段運動錯覺的運動方向判斷產生影響。此外，本研究進一步直接檢驗亮度梯度線段上的注意力分配情形，結果發現高對比端將主動攫取注意力，合併線段運動錯覺方向由低對比端開始的實驗結果，支持將注意力停留位置視作線段運動終點的終點決定假說。本研究最後提出一個模型用以解釋線段運動錯覺的判斷歷程：刺激導向控制歷程及目標導向控制歷程決定亮度梯度線段出現時的注意力分配情形，而事後重建機制藉考慮時間序列中的相關訊息並為注意力攫取位置做出合理的詮釋，進而做出運動方向判斷。

關鍵字

亮度梯度線段

並列摘要

Line motion illusion refers to the phenomenon that when one end of a static line is precued before its presence, observes will perceive this static line as being drawn from the cued end to the uncued end. There are two attention-based accounts of this phenomenon. One is the attentional facilitation model (Hikosaka, Miyauchi, & Shimojo, 1993a) and the other is the end-point hypothesis (Eagleman & Sejowski, 2003). The attentional facilitation model proposed the motion-detecting mechanism involved in the process of motion perception. When the bar presented following a peripheral cue, the cued location of the bar would be perceived earlier than the remaining part by motion-detecting mechanism. Therefore, the attended location would be perceived as the beginning of the motion. The end-point hypothesis considered that the posteriori reconstruction mechanism might contribute to the processing of perceptual information. When an observer found himself attended at one end of a line, this would be interpreted as the end point of line motion. Von Grünau, Saikali and Faubert (1995) used luminance gradient bar to examine the attentional facilitation model. They found that the perceived motion direction began at the high luminance end. They interpreted that the high luminance end would capture attention automatically, resulting in this end being processed earlier than the remaining part of the bar by the motion-detecting mechanism. Therefore, a luminance gradient bar can produce an illusory line motion effect. However, there are two limitations in Von Grünau et al.'s study. First, they used the two-alternate forced choice task which might force participants to select one motion direction when they didn’t perceive any motion. Second, the attentional set of their participants might affect their performance (Downing & Treisman, 1997; Schmidt, 2000). To overcome these two limitations, a third choice of no motion was provided and the attentional set of the participants was manipulated in the present study. Additionally, this study further examined the attentional allocation produced by the luminance gradient bar directly. The results of Experiment 1 and 2 showed that gradient bars did induce line motion illusion, but the control bar didn’t. In addition, the results indicated that the whether there was an option of no motion has no effects on the perceived direction of motion of luminance gradient line. In Experiment 3, we examined the influence of the attentional setting of participants on the judgment of motion direction. And we found that the attentional setting did affect the perceived direction of motion. In addition, the results of Experiments 1 to 3 revealed that the attended location would be perceived as the end of the motion. Therefore, the end-point hypothesis would be supported but not the attentional facilitation model. In the final experiment, we combined the luminance gradient bar procedure with the dot discrimination task to reveal the attention allocation produced by luminance gradient bars. The results showed that the high contrast end of the line gradient bar could capture attention. This finding supported the conclusions of our previous experiments that the high contrast end could captured attention and be perceived as the end of the illusory line motion. These results suggest that the end point hypothesis could provide better explanation for line motion illusion. We proposed that both bottom-up and top-down processes would affect which location would be attended, and which might be perceived as the end of motion by the posteriori reconstruction mechanism (Eagleman & Sejowski, 2003).

並列關鍵字

Luminance Gradient Bar

參考文獻

Adelson, E. H., & Bergen, J. R. (1985). Spatiotemporal energy models for the perception of motion. Optical Society of America, 2, 284-299.

Albrecht, D. G.., & Hamilton, D. B. (1982). Striate cortex of monkey and cat: Contrast response function. Journal of Neurophysiology, 48, 217-237.

Bavelier, D., Schneider, K. A., & Monacelli, A. (2002). Reflexive gaze orienting induces the line-motion illusion. Vision Research, 42, 2817-2827.

Bundesen, C. (1990). A theory of visual-attention. Psychological Review, 97, 523-547.

Chun, M. M., & Marois, R. (2002). The dark side of visual attention. Current Opinion in Neurobiology, 12, 184-189.

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亮度梯度線段之運動錯覺探討：亮度與對比之注意力攫取

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