The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us by Christopher Chabris, Daniel Simons Page A

the ones we have missed. Consequently,all the evidence we have is for good perception of our world. It takes an experience like missing the chest-thumping gorilla, which is hard to explain away (and which we have little incentive to explain away), to show us how much of the world around us we must be missing.
    If the mechanisms of attention are opaque to us, how can we eliminate inattentional blindness so that we can be sure to spot the gorilla? The answer isn’t simple. In order to eliminate inattentional blindness, we would effectively have to eliminate focused attention. We would have to watch the gorilla video without bothering to focus on counting passes or even to focus on what we found interesting in the display. We would have to watch the display without expectations and without goals. But for the human mind, expectations and goals are inextricably intertwined with the most basic processes of perception and are not readily extinguished. Expectations are based on our prior experiences of the world, and perception builds on that experience. Our experience and expectations help us to make sense of what we see, and without them, the visual world would just be an unstructured array of light, a “blooming, buzzing confusion” in the classic words of William James. 49
    For the human brain, attention is essentially a zero-sum game: If we pay more attention to one place, object, or event, we necessarily pay less attention to others. Inattentional blindness is thus a necessary, if unfortunate, by-product of the normal operation of attention and perception. If we are right that inattentional blindness results from inherent limits on the capacity of visual attention, it might be impossible to reduce or eliminate it in general. In essence, trying to eliminate inattentional blindness would be equivalent to asking people to try flying by flapping their arms really rapidly. The structure of the human body doesn’t permit us to fly, just as the structure of the mind doesn’t permit us to consciously perceive everything around us.
    The issue of how best to allocate our limited attention relates to a larger principle of attention. For the most part, inattentional blindness isn’t a problem. In fact, it is a consequence of the way attention works; it is the cost of our exceptional—and exceptionally useful—ability to focus our minds. Focused attention allows us to avoid distraction and use our limited resources more effectively; we don’t want to be distractedby everything else around us. Most drivers follow the rules of the road, most doctors don’t leave guidewires in patients, most fishing vessels aren’t floating right above submarines, most planes aren’t guided in to land right on top of other planes, most cops don’t viciously beat suspects, and most world-class violinists don’t play in the subway. And gorillas rarely saunter through basketball games. Unexpected events are unexpected for a good reason: They are rare. More important, in most cases, failing to spot the unexpected has little consequence.

Attention Writ Large

    The illusion of attention affects us all in both mundane and potentially life-threatening ways—it truly is an everyday illusion. It contributes to everything from traffic accidents and airplane cockpit displays to cell phones, medicine, and even subway busking. As the gorilla experiment has become more widely known, it has been used to explain countless failures of awareness, from the concrete to the abstract, in diverse domains. It’s not just limited to visual attention, but applies equally well to all of our senses and even to broader patterns in the world around us. The gorilla experiment is powerful because it forces people to confront the illusion of attention. It provides an effective metaphor precisely because the illusion of attention has such broad reach. Here are some examples: 50

A trainer uses it to show people how they can miss safety infractions that are right in front of