Abstract
In object recognition, some cognitive processes, such as detection, discrimination, identification and categorization are involved. We have no adequate knowledge about what kind of properties in stimuli are involved in these processes and how these processes are associated with each other. By focusing on the processes of discrimination and identification, the present study aimed to exhibit the difference between these processes. Two experiments were conducted, one about the discrimination task, and the other about the identification task. In the discrimination task, two stimuli of line-drawings objects were briefly presented (200ms) at the center of the screen and observers were asked to judge whether the objects are the same or not. The procedure of the identification task was almost the same except that the target was assigned by a word before two stimuli were presented and observers were asked to choose one of them as the target. Eight objects were selected from Snodgrass and Vanderwart (1980) as stimuli. The background of stimuli was masked by black-and-white random-noise. The stimuli (black line-drawing objects) were also masked probabilistically by random-noise. We analyzed the accuracy and RT on the discrimination and identification tasks and examined the correlation between these values and intrinsic information of line-drawing objects in order to investigate which information is involved in the discrimination and identification processes. The results of both task showed that there is no clear relationship between accuracy and local information in stimuli. However, the difference in holistic complexity has some influences on the discrimination of line-drawing object. On the other hand, identification was related to the contour's factor of object (such as feature points and complexity of object component). Therefore, we assume that the discrimination process involves the comparison of holistic shapes and the identification process involves using strong features of the object as cues.