What Do You See? Emotion May Help the Visual System Jump the Gun to Predict What the Brain Will See
Lee, Jenny Lauren, Science News
You are hiking in the mountains when, out of the corner of your eye, you see something suspiciously snakelike. You freeze and look more carefully, this time identifying the source of your terror: a stick.
Yet you could have sworn it was a snake.
The brain may play tricks, but in this case it was actually doing you a favor. The context--a mountain trail--was right for a snake. So your brain was primed to see one. And the stick was sufficiently snakelike to make your brain jump to a visual conclusion.
But it turns out emotions are involved here, too. A fear of snakes means that given an overwhelming number of items to look at--rocks, shrubs, a hiking buddy--"snake" would take precedence.
Studies show that the brain guesses the identity of objects before it has finished processing all' the sensory information collected by the eyes. And now there is evidence that how you feel may play a part in this guessing game. A number of recent studies show that these two phenomena--the formation of an expectation about what one will see based on context and the visual precedence that emotions give to certain objects--may be related. In fact, they may be inseparable.
New evidence suggests that the brain uses "affect" (pronounced AFF-ect)--a concept researchers use to talk about emotion in a cleaner, more clearly defined way--not only to tell whether an object is important enough to merit further attention, but also to see that object in the first place.
"The idea here is not that if we both see someone smile we would interpret it differently," says Lisa Feldman Barrett of Boston College. "It's that you might see the smile and I might completely miss it." Barrett and Moshe Bar of Harvard Medical School and Massachusetts General Hospital in Boston outline this rather unexpected idea in the May 12 Philosophical Transactions of the Royal Society B: Biological Sciences.
Work connecting emotion to visual processing could have an impact on how scientists understand mental disorders and even personality differences, Barrett says. Some researchers say, for example, that autistic children might literally be failing to see critical social cues. The research might also have implications for understanding traits such as extroversion and introversion: Studies suggest extroverts may view the world through rose-colored glasses, seeing the good more than the bad.
Scientists have long been interested in what role emotions play in recognizing objects, a process of perception that involves both collecting visual information about the world and higher-order workings of the brain.
It takes a few hundred milliseconds for the brain to come to a final decision about what the eyes see. But some basic information about an object--its shape and position in front of the viewer--are sent to the brain at warp speed. The general shape of a gun, for example, is similar to that of a hair dryer or power drill. Only with the additional processing time will the brain be able to confirm which of the three it is looking at. In the meantime, the get-it-quick part of the brain's visual-processing system can send enough information for the brain to take a good, if not always correct, guess at what it's seeing. This guessing process, called visual prediction, is attracting attention from scientists interested in understanding if and how emotion influences visual perception.
In the traditional view, perception, judgment and emotions are considered separate processes, with emotions coming last in the procession. One perceives. One judges, using reason, what best to do with the information collected. And one keeps one's emotions, as much as possible, out of the picture.
But in the early 1980s, some researchers began to think that affect plays an earlier role in object recognition. Researchers were struck by experiments in which people seemed to feel an emotion without being able to identify the object that had elicited it. …