Loosening the constraints on illusory conjunctions: assessing the roles of exposure duration and attention.

Illusory conjunctions are the incorrect combination of correctly perceived features, such as color and shape. They have been found to occur using a brief exposure (under 200 ms) and a dual task designed to divert attention. The present study investigated the roles of exposure duration and attention in obtaining illusory conjunctions. Several mathematical models of the feature integration task were also assessed. Experiment 1 tested participants' accuracy at combining features using a long exposure and an attention-diverting taks. Experiment 2 compared performance with and without the attention-diverting task. The final experiment compared performance using a brief (0.15 s) and a long (1.5 s) exposure duration without an attention-diverting task. Neither attention nor exposure duration had a significant effect on feature integration.