Orienting or intention? Unconscious processing of human gaze
Yi-Chia Chen & Su-Ling Yeh
National Taiwan University
Human gaze indicates the direction of next action, which is so important that even a chimpanzee can detect it (Tomonaga & Imura, 2010). We examine whether human gaze can be processed unconsciously when the face presented to one eye is made completely invisible for some time due to dynamic masks that was presented to the other eye (The continuous flash suppression paradigm). In Experiment 1, gaze and head orientation were the same, and we presented a schematic face in one of the six versions of facial expression (happy, fearful, neutral expression) x head orientation (direct, averted). Participants were asked to detect the face and the time to release from suppression was used as an index of processing time. Faster detection time was found for faces with direct orientation than with averted one regardless of expressions. Experiment 2 kept the head orientation constant (in front) but manipulated gaze direction to eliminate the low-level feature effect such as symmetrical vs. asymmetrical configuration in direct vs. averted head orientation respectively. The same results were found. Experiment 3 tested two hypotheses. First, the averted gaze induces attentional orienting, which causes one’s attention to shift away from the target and thus impairs its detection. Second, direct gaze carries “intention to you” information and facilitates processing because it is self-relevant. Upright, inverted, and eye-only conditions were manipulated. Results showed no difference between these conditions, supporting the attentional orienting account. In sum, gaze direction can be processed unconsciously through attentional orienting induced by averted gaze.
This research is supported by National Science Council of Taiwan (NSC 99-2815-C-002-108-H, NSC 96-2413-H-002-009-MY3, and NSC 98-2410-H-002-023-MY3).