知觉经验对面孔整体加工的影响

基于经验的整体加工理论认为, 随着知觉经验的增多, 人们加工面孔的专家化能力逐渐增强。其中一种表现形式为, 在知觉面孔时更倾向于整体加工。该理论已经得到了一些实验证据的支持, 但未能解释另外一些研究的发现, 即对他族人群没有长期知觉经验的被试在加工他族面孔时也有强烈的整体加工。本研究旨在考察知觉经验对面孔整体加工的影响, 包括两个实验。实验1a通过组合面孔范式测量了中国被试在辨别本族面孔、他族面孔和种族融合面孔时的组合面孔效应(即面孔整体加工强度)。结果发现, 被试在知觉种族融合面孔时没有表现出组合面孔效应, 在知觉本族面孔和他族面孔时都表现出强烈的组合面孔效应。实验1b以灰阶图重复了实验1a。结果发现, 被试在知觉种族融合面孔时仍然没有表现出组合面孔效应, 在知觉本族面孔和他族面孔时表现出强烈的组合面孔效应。实验2通过操纵种族融合面孔的有或无, 测量5 s的知觉经验对融合面孔的组合效应的影响。结果发现, 在经过短时的知觉经验后, 被试在知觉融合面孔时也表现出强烈的组合面孔效应。上述实验结果表明, 中国被试在加工本族面孔、他族面孔和种族融合面孔时所诱发组合面孔效应有显著的、量的差别, 且这种整体加工的差异不会受到面孔肤色信息的影响。在经过短时的知觉经验后, 中国被试在加工种族融合面孔时表现出强烈的整体加工。该研究的发现提示, 不论是短时知觉经验还是长期知觉经验, 知觉经验的增加是面孔整体加工的一个关键要素。

Face holistic processing is modulated by perceptual experience

It is well known that same-race faces are better discriminated and recognized than other-race faces, a phenomenon confirmed experimentally and termed in the literature for face perception as the “own-race advantage”. Why do people have the bias in face processing? Some researchers claimed that the own-race advantage in discrimination is associated with interracial contact. The more visual experience with own race faces, the better discrimination within own-race faces. How visual experience affects the processing of same-race and other-race faces has yet to be determined. An influential hypothesis “experience-based holistic processing view” states that it would result from a reduced holistic processing with which we have less experience. To examine the effect of perceptual experience on holistic processing, with composite face paradigm and perceptual adaptation paradigm we investigated the composite-face effect of own-race faces, other-race faces and morphed faces during the perceptual discrimination. In the preliminary experiment, 20 Asian participants were presented with 704 color Asian-Caucasian morphed face stimuli for a race categorization task. These stimuli were generated with morphing software (MorphTM), allowing the creation of 11 blended face stimuli (from 0:100 to 100:0 for Asian:Caucasian proportions, respectively) for each of 64 Asian-Caucasian continua. In each continuum, the face that was equally often categorized as Asian and as Caucasian was identified as the ambiguous-race face. Result showed that the 52 Asian-Caucasian ambiguous faces were extracted and used as face stimuli in experiment 1a, experiment 1b and experiment 2. In Experiment 1a, we examined the holistic processing of own-race faces and other-race faces by using the composite paradigm in a two-alternative forced-choice delayed matching task. The results of Exp1a showed that own-race faces and other-race faces are processed holistically. However, morphed faces are not processed holistically. With gray pictures as stimuli, Exp1b replicated the same results as experiment 1a. In Experiment 2, we examined that the holistic processing of morphed faces can be induced by perceptual adaptation (5 seconds). Results showed that the morphed faces were processed holistically after short-term perceptual adaptation. Collectively, these findings indicate that face holistic processing is modulated by perceptual experience, even the short-term perceptual adaptation may affect participants’ face holistic processing as one of the most important factors.