動態深度效果的反轉：細節均質性與熟悉度因素影響

Reversion of the Kinetic Depth Effect: Interaction between Homogeneity and Familiarity

觀者將二維剪影或網格影像看成三維物體旋轉的現象被稱為動態深度效果（KDE, Wallach & O'Connell, 1953）。由於 KDE 影像缺乏深度線索，因此觀者無法掌握圖形的旋轉方向，甚至會感覺到圖形在旋轉過程中發生 反轉。Klopfer（1991）以人臉面具作為 KDE 影像的素材，發現面具在旋轉過程中有極高的反轉次數，並以 Gregory （1980）提出的熟悉度因素進行解釋，主張觀者對圖形的熟悉度與反轉次數呈正相關，然而熟悉度因素卻無法解釋 面具以外的 KDE 影像。本研究旨在驗證是否有造成 KDE 影像反轉的基礎因素，能夠廣泛解釋人臉與非人臉圖形， 而非將人臉當成理論的特例。本研究假設 KDE 影像的 2 種深度表象會在旋轉過程中切換，而圖形的細節均質性則 會影響深度表象的切換頻率，造成圖形更傾向於發生反轉或穩定旋轉。本研究以電腦繪圖的奈克方塊與人臉面具作 為材料，透過 2 個實驗來驗證圖形細節均質性是否能夠解釋 KDE 影像的反轉頻率，並排除熟悉度因素的影響。實 驗結果發現：圖形細節均質性會影響圖形的深度表象切換，進一步造成反轉頻率的差異。當圖形的細節分佈不均， 反轉頻率就較高；當圖形的細節分佈均質，則要考量對立兩面的表象競爭。此外，以人臉面具作為實驗材料時，實 驗結果並無法排除熟悉度因素的影響，當圖形越接近日常所見的人臉外觀，反轉頻率就越高。考量上述因素的共同 作用，可能更適合說明旋轉面具錯覺的成因。

The kinetic depth effect (KDE) (Wallach & O'Connell, 1953) is a phenomenon in which an observer can perceive 3D rotation from continuously presented 2D projection images. Each frame of a projected 2D image does not contain enough depth cues, so the direction of rotation is unstable in the KDE, and the object is perceived as spontaneously reversing (oscillating). Blackburn (2011) reviewed numerous studies and proposed that adding a temporal or spatial dimension may disambiguate the KDE. Klopfer (1991) used masks of the human face as stimuli in his experiment and found that the masks appeared to oscillate rather than rotate. This phenomenon may be attributed to the familiarity factor, in that observers are more familiar with convex faces than with concave faces. However, the familiarity factor could not explain the perceived reversal of non-face KDE stimuli. This study aimed to identify the general factors that can explain the reversal of rotating masks and non-face stimuli. We hypothesized that KDE stimuli reverse during the alternation of two depth appearances, and that nonhomogeneous features alternate more than homogeneous features. The rotating mask illusion may be attributed to its nonhomogeneity. In this study, Necker cubes and masks were used as stimuli in two experiments to discern whether the relationship between the homogeneity factor and the familiarity factor influences the number of KDE stimuli perceived to reverse. The results of the two experiments support the hypothesis that both the homogeneity factor and familiarity factor influence the perceived reversal of KDE stimuli.