Effects of Discrimination Difficulty on the Identification of Different Types of Visual Forms

The effects of different levels of discrimination difficulty on form perception were measured for two types of shapes; namely, 6 by 6 constrained metric polygons and histoforms. Five levels of discrimination difficulty were provided by use of different degrees of similarity between target and choice figures; 120 Ss (12 in each of 10 experimental conditions) responded in a paper-and-pencil figure-cancellation task. Separate analyses of errors and response times indicated that the polygons were identified more quickly but less accurately than the histoforms. Overall performance was better with polygons than with histoforms.