Ambiguity and Reentrant Processing in Object Detection

Many scientists continue to conceive of object detection as occurring in stages that map onto levels in the visual hierarchy. This article reviews experiments suggesting that multiple interpretations and their semantics are activated at high levels before conscious object detection. That more than one interpretation is activated before object detection implies that ambiguity (and not just uncertainty) exists before conscious object detection. This is so even when displays seem unambiguous after detection. Converging evidence from a variety of methods indicates that inhibitory competition resolves the unconscious ambiguity. Experiments in my laboratory suggest that reentrant processes—both cortico-cortical and cortico-subcortical—determine conscious perception. I conclude that object detection entails global dynamic interactive Bayesian processes. Stage terminology is outdated.