Carmody D P, Nodine C F, Locher P J
Percept Mot Skills. 1977 Dec;45(3 Pt 2):1267-73. doi: 10.2466/pms.1977.45.3f.1267.
Two experimental approaches examined observers' ability to characterize shape symmetry based upon the information obtained within a single fixation. Exp. I tested observers' ability to discriminate among three levels of symmetry on the basis of a 25-msec. presentation. Results indicated that identification accuracy was higher for symmetrical and asymmetrical shapes than for mixed shapes, which contained both symmetrical and asymmetrical components. Exp. II tested observers' ability to detect a given level of symmetry by means of a signal-detection approach. Symmetrical shapes were detected better than asymmetrical shapes. Detectability of mixed shapes was lower than that for both symmetrical and asymmetrical shapes. The results of Exps. I and II demonstrate that observers can characterize shape symmetry on the basis of information available within a single fixation. The data are supportive of the hypothesis that a global response to the over-all configuration of the shape serves to facilitate form perception.
两种实验方法考察了观察者根据单次注视所获得的信息来表征形状对称性的能力。实验一测试了观察者基于25毫秒呈现来区分三种对称水平的能力。结果表明，对称和不对称形状的识别准确率高于包含对称和不对称成分的混合形状。实验二通过信号检测方法测试了观察者检测给定对称水平的能力。对称形状比不对称形状更容易被检测到。混合形状的可检测性低于对称和不对称形状。实验一和实验二的结果表明，观察者可以根据单次注视中可用的信息来表征形状对称性。这些数据支持了这样一种假设，即对形状整体构型的全局反应有助于促进形状感知。
