Abstract
In motion-induced blindness (MIB), a static target superimposed on a global moving pattern frequently disappears and reappears into consciousness. We previously reported an intriguing illusory temporal reversal whereby a sudden onset stimulus (e.g., a flash) presented during MIB triggers an early reappearance of the target, yet is systematically perceived as occurring after the target reappearance. This illusion implies that the unconscious target representation can be quickly reactivated, with faster conscious access compared to novel stimuli. What is the nature of this unconscious representation: is it a memory of the stimulus that just disappeared, or is it a faithful representation of the input â€"only unconscious? In the former case but not the latter, the unconscious representation might be expected to decay over time, together with its temporal advantage for conscious access. Here we addressed this question by examining the relationship across observers between the duration of MIB and the percentage of illusory temporal reversals. In the pretest session of regular MIB (200 trials), participants (n = 28) reported the perceptual disappearance and reappearance of a ring target, from which we computed the first (Q25), second (Q50), and third quartiles (Q75) of each participant’s MIB duration distribution. In each trial of the test session, after the reported onset of MIB, a dot probe was flashed at the location of the ring at the exact time delay corresponding to either the Q25, Q50, or Q75 value; participants judged the perceived temporal order of the dot and ring. For all 3 conditions, the percentage of illusory reversals was negatively correlated across participants with the corresponding quartile value (p=.01, p=.0001, and p=.02, for Q25, Q50 and Q75, respectively). Therefore, our data suggest that unconscious representations are like a memory that decays over time during MIB and thus decreases its temporal advantage for regaining conscious access.
Meeting abstract presented at VSS 2014