I mean: look at an image for a second. Can you only remember 10 things about it?

The paper actually talks about the winners of memory championships (memorizing random strings of numbers or the precise order of a random arrangement of a 52-card deck). The winners tend to have to study the information for an amount of time roughly equivalent to 10 bits per second.

It even talks about the guy who was given a 45 minute helicopter ride over Rome and asked to draw the buildings from memory. He made certain mistakes, showing that he essentially memorized the positions and architectural styles of 1000 buildings chosen out of 1000 possibilities, for an effective bit rate of 4 bits/s.

That experience suggests that we may compress our knowledge by taking shortcuts, some of which are inaccurate. It’s much easier to memorize details in a picture where everything looks normal, than it is to memorize details about a random assortment of shapes and colors.

So even if I can name 10 things about a picture, it might be that those 10 things aren’t sufficiently independent from one another to represent 10 bits of entropy.