Abstract
While it is quite evident that we are not aware of all cortical activity, evidence is still sparse concerning what unconscious information is usable for task performance. The famous case of Blindsight underscores the importance of this issue - in brains with specific damage. We present three cases of the use of information of which (healthy) participants are not consciously aware.
1. Following brief presentation of four pacman-like forms, which describe a rectangle, a triangle (by three pacmen), or no form at all (e.g. with jumbled or outward-facing pacmen), subjects often report that they have not detected the illusory contour form, (when one was present), but they are nevertheless well above chance at guessing its shape.
2. Searching for a pair of identical patterns in an array of otherwise heterogeneous patterns, (with target present in 50% of trials), eye movement patterns reflect early concentration on the target (when present), well before participants are aware of its presence.
3. In a novel search task, performance is enhanced by use of utrocular (eye-of-origin) information, which participants are wholly unaware of.
These examples demonstrate not only that information of which we are unaware is usable for task performance, it also points to the high-level nature of such unconscious information. As in Reverse Hierarchy Theory, these phenomena point to a site-independent neural correlate of conscious perception.
Israel Science Foundation (ISF).