Mind Hacks

Hack #40. Blind to Change

We don’t memorize every detail of a visual scene. Instead, we use the world as its own best representation—continually revisiting any bits we want to think about. This saves the brain time and resources, but can make us blind to changes.

Both our vision [[Hack #14]] and attention [[Hack #34]] have far coarser resolutions than we’d have thought. What’s more, there are gaps in our vision across time [[Hack #17]] and in space [[Hack #16]], but our brains compensate for these gaps and knit together a rather seamless impression of the world.

And this gapless impression is utterly convincing. Most of the time we don’t even realize that there are holes in the information we’re getting. And so we believe we experience more of the world than we actually do. There are two possibilities as to what’s going on here. The first is that we build a model inside our heads of the world we can see. You can test to see whether this is the case.

Imagine you are looking at a picture. There’s a flicker as the picture disappears and appears again. What’s different? If we made and kept a full internal representation of the visual world inside our heads, it would be easy to spot the difference. In theory—before memory decay set in—it should be as easy as comparing two pictures (before and after) side by side on a page. But it isn’t.

So that puts paid to the first possibility. The other is that you don’t build a full internal model of what you’re seeing at all—you just think you do. The ...