Mind Hacks

Hack #34. Detail and the Limits of Attention

Focusing on detail is limited by both the construction of the eye and the attention systems of the brain.

What’s the finest detail you can see? If you’re looking at a computer screen from about 3 meters away, 2 pixels have to be separated by about a millimeter or more for them not to blur into one. That’s the highest your eye’s resolution goes.

But making out detail in real life isn’t just a matter of discerning the difference between 1 and 2 pixels. It’s a matter of being able to focus on fine-grain detail among enormously crowded patterns, and that’s more to do with the limits of the brain’s visual processing than what the eye can do. What you’re able to see and what you’re able to look at aren’t the same.

In Action

Figure 3-1 shows two sets of bars. One set of bars is within the resolution of attention, allowing you to make out details. The other obscures your ability to differentiate particularly well by crowding. ¹

Figure 3-1. One set of bars is within the resolution of attention (right), the other is too detailed (left) ¹

Hold this book up and fix your gaze on the cross in the middle of Figure 3-1. To notice the difference, you have to be able to move your focus around without moving your eyes—it does come naturally, but it can feel odd doing it deliberately for the first time. Be sure not to shift your eyes at all, and notice that you ...