Enjoying EarthSky? Subscribe.

102,146 subscribers and counting ...

By in
| Human World on Jun 16, 2011

Two types of perception linked in surprising way

The mind is a great statistician, say psychologists studying two types of perception.

Scientists have found a surprising connection between two types of perception. If you’re looking at a group of objects and getting a general sense of them, it’s difficult for your brain to learn relationships between the objects. This study of statistical summary perception and statistical learning by Nicholas Turk-Browne of Princeton University and his team was accepted for publication in Psychological Science, a journal of the Association for Psychological Science.

Image Credit: VinothChander

Assistant professor Turk-Browne said these two types of perception involve statistics, though their exact relationship to one another is unknown. In statistical summary perception, your brain calculates general properties from a brief glance. He gave an example:

If I’m looking at a roomful of faces, how happy are people on average?

Or, by looking out a window, someone could sense what season it is, based on the general color and presence of leaves on trees.

The other is called statistical learning – finding patterns in the world over time. Turk-Browne said:

After seeing the front of the psychology building at Princeton, [you know that you are] much more likely to see my face than the face of your favorite actor.

Patterns are everywhere, and learning about them helps in acquiring language, predicting the trajectory of a tennis ball or discovering the layout of a building. Turk-Browne said:

Even though these two cognitive processes are different, they’re both inherently statistical.

'Patterns made by palm trees, shadows, and the pavement. Image Credit: cybaea

Turk-Browne and his colleagues devised a study to determine how these two ways of seeing were entangled. They showed people grids that contained lines slanted to varying degrees. Some people were asked to do summary perception – to decide whether the lines were generally leaning to the left or the right. Others were asked to answer a different question or just to look at the lines. At the end of the experiment, people who did summary perception displayed no statistical learning – they were unable to recognize pairs of lines that had been hidden repeatedly in the grids.

This shows that when you’re extracting the general properties of a set of objects, you’re not able to learn about their relationships, Turk-Browne says. Other experiments found that the reverse was also true – when there are relationships to be learned, you’re worse at perceiving general properties.

The overall goal for Turk-Browne and his colleagues is to learn how your brain changes as you interact with the world. He said:

Every moment your eyes are open, your brain is changing in sophisticated ways. What’s cool about this study is that it demonstrates that your mind is a great statistician, and you don’t even realize it.

Experiments like these help psychological scientists understand how the brain perceives the world and give hints about the unconscious calculations the brain is making all of the time.

Bottom line: Nicholas Turk-Browne of Princeton University and his team conducted a study showing an important connection between statistical summary perception and statistical learning. Their paper has been accepted for publication in Psychological Science.

Via Association for Psychological Science

A cluttered mind doesn’t remember