When you look around the world, lots of different things may capture your attention. The loud backfire of a car nearby may cause you to look in that direction. A bright flash of light from a window can get you to look up. A familiar face in a crowd can lead you to focus on it. An object that suddenly starts moving can grab your attention.
It makes sense that you would pay attention to this kind of information in the world. Loud sounds and bright lights may signal danger or something surprising. You shift your attention to figure out how to deal with this new event.
You are more likely to want to interact with a familiar person than an unfamiliar one, and so your attention is drawn to the familiar people in a crowd of unfamiliar ones.
Something that suddenly starts moving may do something interesting, and so you want to check it out to help you understand what is happening in the world.
A fascinating new paper in the May 2013 issue of Psychological Science by Jiaying Zhao, Naseem Al-Aidroos, and Nicholas Turk-Browne examined how the regularity in a sequence might affect attention. The idea is that when an aspect of the world is predictable in a sea of randomness, then you might want to pay attention to the predictable part of the world (in much the same way that you pay attention to a familiar face in a crowd).
The design of the study is clever, but a little complicated.
In one study, participants focused their attention on a cross at the center of a computer screen. Above, below, left, and right of the cross sequences of shapes were shown. Each shape appeared for three-quarters of a second with a delay between shapes. At three of the locations the sequence of shapes was random. There was no way to predict which shape would next at that location.
At the fourth location, the sequence was predictable. For this group, there were nine shapes overall, and they were divided into three groups of three-shape triplets. The shapes in a triplet always appeared in the same order in that sequence of shapes.
Now, how could you tell whether people are paying more attention to the predictable sequence than to the random sequences?
Every once in a while, the stream of shapes on the screen was interrupted by a test. On the test trials, three of the locations had a letter L that was facing to the left or the right. The fourth location had a sideways letter T that was facing either to the left or the right. Participants had to find the letter T and then press a button to say whether it was facing to the right or to the left.
On these test trials, people were faster to respond when the T appeared in the same location on the screen as the predictable sequence than when it appeared in the location of one of the random sequences. This result suggests that people were shifting their attention toward the predictable sequence, and so when a test trial came, they found the T more easily when it also appeared in the same location as the predictable sequence.
Another study in this sequence demonstrated a similar effect where the marker of the predictable sequence was the color of the shapes rather than their location.
What is going on here?
You are constantly making decisions about where to focus your attention. The world is a busy place, and you have to figure out what information is likely to be most important.
Structure in the world is much more likely to be important than randomness. When things appear randomly, then chances are that is happening because they are unrelated to each other. There is no point in paying attention to the random sequence, because it is not likely to occur again.
But, structured sequences may reflect that there really is something about the way the world works that causes the items to appear in that sequence. So, it is a good idea to pay attention to the predictable sequence.
The fascinating thing about this mechanism is that it works unconsciously. People are not aware that they are learning predictable sequences. They are also not aware that they are shifting their attention toward the predictable sequence. All of this learning happens simply as a result of the way the attention system operates.