A brain in doubt leaves it out: Motion-Induced Blindness

Jyoti Pandit, B.Optom

Paediatric Fellow Optometrist, Dr. Shroff’s Charity Eye Hospital, New Delhi, India

 

The human visual system is an intricate marvel that constantly processes an overwhelming amount of information. Yet, despite its remarkable capabilities, our perception can be subject to intriguing and bewildering phenomena. We are the prisoners of our brain. Sometimes, the brain ignores what the eyes tell it. We only see what it decides to let us see. Researchers now illustrate this with an illusion in which the brain erases some aspects of the visual field. The illusion catches the brain ignoring or discarding information. This may be one of the brain’s useful tricks, a deficiency- or perhaps both. ⁽¹⁾ This phenomenon could happen in everyday life without us noticing it.

Understanding Motion-Induced Blindness:

Motion-induced blindness (MIB) also known as Bonneh’s illusion is a visual phenomenon in which a salient static target spontaneously fluctuates in and out of visual awareness when surrounded by a moving mask pattern. Perhaps the most remarkable feature of MIB is that objects can disappear even when they are moving. MIB is complementary to other perceptual phenomena, such as binocular rivalry in which the perception fluctuates spontaneously in the face of constant physical stimulation. ⁽¹⁾

The Experiment:

A typical MIB display is exceedingly simple (Figure 1): an observer fixates at the Centre of the display, and views two stimuli:

1. A bright yellow disc (the “target”), and
2. A grid of blue crosses (the “mask”) that rotates continuously about the fixation point.

Figure 1. Still-frames of a typical MIB display.
Image courtesy: https://upload.wikimedia.org/wikipedia/commons/0/03/MotionBlindnessf.gif

Observers fixate the white concentric circles in the display centre while attending to the solid yellow target disc in the upper left. When the mask made of crosses smoothly rotates, the target repeatedly disappears, even when attended. ⁽²⁾

Though the target is always present in the display, it disappears from conscious awareness, often for several seconds at a time, over and over, and despite the observer’s full knowledge of the nature of the display. ^(3,4)

Daily Life Example:

Motion-induced blindness can occur in various everyday situations, like walking, driving, sailing, flying, hunting, biking, skiing and so many other activities of daily life, often without us even realising it. It is the effect whereby objects that are stationary simply vanish from our peripheral sight with respect to the things that are moving.

Pilots were taught to alternate their gaze between scanning the horizon and scanning their instrument panel and never to fix their gaze for more than a couple of seconds on any single object. If he fixes his gaze on one object long enough, while he himself is in motion, his peripheral vision goes blind. That is why it is called motion induced blindness. ⁽⁴⁾

It is important to note that in daily life, we might not always consciously perceive these momentary disappearances because our attention quickly shifts to other objects or events. However, by paying closer attention to our visual experiences, we can occasionally catch glimpses of motion-induced blindness in action.

Conclusion:

Motion-induced blindness invites us to question the reliability of our visual perception and illuminates the intricacies of the human visual system. This captivating illusion provides a window to the complex interplay between attention, motion processing, and conscious awareness. By studying motion-induced blindness, scientists continue to uncover the secrets of our perception and pave the way for practical applications and advancements in our understanding of various neurological conditions.

 

References:

1. Donner, T. H., Sagi, D., Bonneh, Y. S., & Heeger, D. J. (2008). Opposite neural signatures of motion-induced blindness in human dorsal and ventral visual cortex. Journal of Neuroscience, 28(41), 10298-10310.
2. Bonneh, Y. S., Cooperman, A., & Sagi, D. (2001). Motion-induced blindness in normal observers. Nature, 411(6839), 798-801.
3. Khayat, N., & Hochstein, S. (2018). Perceiving set mean and range: Automaticity and precision. Journal of Vision, 18(9), 23-23.
4. Bonneh, Y., & Donner, T. (2011). Motion induced blindness. Scholarpedia, 6(6), 3321.