The flick of the wrist and the wave of the wand: Low-level mechanisms for inducing change blindness

This dissertation explores a new paradigm for inducing change blindness as an avenue for understanding the stimulus conditions that give rise to change blindness in general. Participants are asked to detect an instantaneous change in orientation of a single item in an array of Gabor patches. While looking for the orientation change, the array moves across the display, abruptly changing its direction of motion at a single point of flexion. Observers show little trouble spotting the rotation if it occurs while the array is moving continuously along a straight path; however, detection is impaired when the rotation occurs simultaneous with an abrupt change in direction of at least 90?. A potential neural mechanism is proposed involving the interference of excitatory signals to motion receptors in visual cortex, and that theory is extended to the creation of new paradigms for suppressing change detection. In one-shot and continuous change detection tasks, transient color-change signals conceal targets that change color and transient motion signals conceal targets that generate motion, but each one is relatively ineffective at hiding the other. Based on these data, this thesis proposes a theory of “change camouflage” as a means of explaining the variety of change blindness phenomena found here and the change blindness literature at large