# Motion-Induced Blindness ## Motion-Induced Blindness This paper was originally intended to discuss a phenomenon called Adaptation-Induced Blindness, a phenomenon wherein the human visual system adapts to changing patterns of contrasting colors which can prevent the perception of a static version of the pattern that follows (Stier, 2011), however research on the subject is rather sparse. Instead, this paper will focus on another related phenomenon that is more heavily researched – Motion-Induced Blindness (MIB). MIB is a phenomenon in which stationary dots on a screen will disappear while a field of moving dots is being displayed and when gaze is maintained on a central location. Research on this topic is more readily available; nevertheless there is no consensus about the specific mechanisms responsible for this phenomenon (Wallis & Arnold, 2009). ## History This phenomenon was originally discovered by Grindley and Townsend in the 1967 but did not get examined closely until it was found again with recent computer graphics (Bonneh & Donner, 2011). The targets are the stationary dots that disappear whereas the mask is the moving pattern in the background. ## Conditions This illusion occurs under specific conditions that may be generalizable to natural settings (Bonneh, Cooperman, & Sagi, 2001). According to Bonneh and Donner (2011), MIB occurs when the target is small, located further from the point of fixation (the effect is particularly strong when the target is in the upper quadrant of the visual field), when the target is stationary or slowly moving, and that the target disappears more readily when it is in strong contrast to the background. They also explain that MIB changes its phenomenological characteristics in response to whether or not the targets form a group – disappearing together if so and disappearing alternately if not. Phenomenology such as this demonstrates the Gestalt principles of perceptual organization. The in-depth explanation by Bonneh and Donner (2011) lists one final and interesting condition that can impact the strength of the MIB effect: the mask itself can be randomly moving dots in either 2D or 3D patterns, rotating surfaces, or drifting patterns as well as flickering stimuli near the target. ## Neurological Basis Understanding of MIB at a neurological level is still incomplete, however it has made steady progress over the last decade. There has been much debate surrounding what neural mechanisms might play a role in the phenomenon, particularly due to the behavioral data providing insights into possible underlying neural mechanisms. Recent research by Scholvinck and Rees (2009) has revealed that MIB may very well occur due to processes in both low-level visual areas and higher-level visual cortical areas. That is to say, MIB may be a product of both neurons that process contours and surfaces as well as neurons involved in attention processes. While their use of fMRI did not allow for enough spatial resolution to distinguish between certain low-level visual processes, they were able to infer that MIB is due to activity in V1 and V2 as well as V5/MT. Additionally, although they were unable to find conclusive evidence for higher-level cortical involvement, they did propose a mechanism by which high-level cortical pr ocesses could feedback into low-level visual areas and thereby modulate the activity in V1/V2. Finally, Scholvinck and Rees (2009) propose that their study may provide evidence for “an additional [neural] mechanism that is specific to this state of target invisibility” which is particularly interesting. ## Discussion If a specific neural mechanism underlying the MIB invisibility phenomenon exists, then it would be safe to infer that there is some evolutionary advantage that caused the development of this mechanism. Perhaps MIB is the result of neural mechanisms that have evolved to allow phylogenetic ancestors that spent much time in stationary hunting positions to focus on patterns of movement without being distracted by other stationary visual stimuli in proximity to the center of the visual field. Another possibility is that MIB is an adaptation for visually complex flocking or schooling organisms in the air or water to focus on the patterns below or passing by and ignore immediate neighbors. This might help explain the utility of the alternations in target invisibility as well as the upper visual field preference for MIB occurrence – perhaps lower flying birds or swimming fish adapted by finding more signs of food and therefore having a better chance of surviving in nature. ## References Bonneh, Y., Cooperman, A., & Sagi, D. (2001). Motion-induced blindness in normal observers. Nature. 411:798-801. Bonneh, Y. and Donner, T. (2011). Motion induced blindness. Scholarpedia. 6(6):3321. doi:10.4249/scholarpedia.3321 Scholvinck, M. and Rees, G. (2009). Neural correlates of Motion-induced Blindness in the human brain. Journal of Cognitive Neuroscience. 22(6):1235-1245. Stier, C. (2011, November 4). Friday illusion: Pattern causes temporary blindness [Web log message]. Retrieved from http://www.newscientist.com/blogs/nstv/2011/11/friday-illusion-flashing-os-blind-letter-reappearance.html?DCMP=OTC-rss&nsref=online-news Wallis, T. and Arnold, D. (2009). Motion-induced blindness and Motion Streak Suppression. Current Biology. 19:325-329.