Abstract
This study investigates the effects of fixation and passive attention on object recognition task. It is known that attention and fixation play an important role for object recognition, but it is unclear yet that the interaction between fixation and passive attention. Attention can shift to another location independently without eye movement (Posner, 1980). We controlled the observers' fixation and passive attention to test the interaction on the recognition task. In the experiments, observers asked to gaze the one of two boxes indicated by the arrow on the display. In the course of fixation, one box color changed in order to capture passive attention. After the cue lead time, we presented an object in the one of two boxes followed by the mask. When a test stimulus was shown observers were required to report whether the test stimulus was the same object as presented before. There were four experimental conditions: (a) fixation/cue-valid, (b) fixation/cue-invalid, (c) no-fixation/cue-valid, (d) no-fixation/cue-invalid. Under the conditions of no-fixation (c, d) the performances dropped in comparison with the fixation conditions (a, b). However there are two different kinds of mis-judgements at incorrect responses. First, observers responded as “same” when the target and test stimulus were different. It means that the failure of the change detection occurs. Second, observers gave their responses as “different” when the same objects were presented, this suggests that human visual system could not occasionally integrate the representations of two objects.
This work was supported by MEXT. Japan ORC (2005–2009).