Rapid recognition of unseen objects in natural scenes: Does your brain know what you didn't see? W Zhu1, J Drewes2, Y Li1, F Yang, X Du3, K R Gegenfurtner4 |
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1Kunming Institute of Zoology, Yunnan University, China |
| The visual system has a remarkable capability to extract categorical information from complex natural scenes (Thorpe, Fize, & Marlot, 1996). However, it is not clear whether rapid object recognition needs awareness. We recorded event-related potentials (ERPs) during a continuous flashed suppression paradigm (CFS) (Tsuchiya & Koch, 2005), in which the luminance and contrast were controlled to ensured around half of the images were seen by our subjects. In experiment 1, both animal and non-animal images were shown 500ms, and subjects were required to perform target (animal) detection: Did they see animal or non-animal images? ERP results showed animal images induced bigger amplitudes than non-animal images on “seen” condition, but smaller amplitudes than non-animal images on “unseen” condition (F(1,75)=4.78, p=0.032) In experiment 2, non-animal images were replaced with vehicle images, and subjects needed to categorize: Did they see animal or vehicle images? As in experiment 1, animal images induced bigger amplitudes than vehicle images on “seen” condition, but smaller amplitudes than vehicle images on “unseen” condition (F(1,75)=21.7, p<0.001). Our results indicate that even in the “unseen” condition, the brain responds differently on animal and non-animal/vehicle images and the rapid processing of animal images might differ in conscious and unconscious conditions. |
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