We're using computers for so long now that I guess that many of you think that our brains are working like clusters of computers. Like them, we can do several things 'simultaneously' with our 'processors.' But each of these processors, in our brain or in a cluster of computers, is supposed to act sequentially. Not so fast! According to a new study from Cornell University, this is not true, and our mental processing is continuous. By tracking mouse movements of students working with their computers, the researchers found that our learning process was similar to other biological organisms: we're not learning through a series of 0's and 1's. Instead, our brain is cascading through shades of grey. Read more.
According to this study, learning -- at least language comprehension -- is a continuous process.
"For decades, the cognitive and neural sciences have treated mental processes as though they involved passing discrete packets of information in a strictly feed-forward fashion from one cognitive module to the next or in a string of individuated binary symbols -- like a digital computer," said Michael Spivey, a psycholinguist and associate professor of psychology at Cornell.
His experiments are somewhat fascinating -- even if limited.
In his study, 42 students listened to instructions to click on pictures of different objects on a computer screen. When the students heard a word, such as "candle," and were presented with two pictures whose names did not sound alike, such as a candle and a jacket, the trajectories of their mouse movements were quite straight and directly to the candle.
The picture below shows Michael Spivey with one of his students looking at two objects on her screen.
[He asked her] to listen for a word and then to click on its picture. By studying the curvature of the trajectory of the mouse, he can analyze language comprehension processes (Credit: Kevin Stearns, Cornell University).
I read the newspapers avidly. It is my one form of continuous fiction.
—Aneurin Bevan (1897–1960)
But when the students heard "candle" and were presented with two pictures with similarly sounding names, such as candle and candy, they were slower to click on the correct object, and their mouse trajectories were much more curved. Spivey said that the listeners started processing what they heard even before the entire word was spoken.
Spivey concludes that our brains can handle ambiguities.
"When there was ambiguity, the participants briefly didn't know which picture was correct and so for several dozen milliseconds, they were in multiple states at once. They didn't move all the way to one picture and then correct their movement if they realized they were wrong, but instead they traveled through an intermediate gray area," explained Spivey.
For more information, the research work has been published online by the Proceedings of the National Academy of Sciences under the name "Continuous attraction toward phonological competitors." Here is a link to the abstract.
Certain models of spoken-language processing, like those for many other perceptual and cognitive processes, posit continuous uptake of sensory input and dynamic competition between simultaneously active representations. Here, we provide compelling evidence for this continuity assumption by using a continuous response, hand movements, to track the temporal dynamics of lexical activations during real-time spoken-word recognition in a visual context. By recording the streaming x, y coordinates of continuous goal-directed hand movement in a spoken-language task, online accrual of acoustic-phonetic input and competition between partially active lexical representations are revealed in the shape of the movement trajectories. This hand-movement paradigm allows one to project the internal processing of spoken-word recognition onto a two-dimensional layout of continuous motor output, providing a concrete visualization of the attractor dynamics involved in language processing.
The access to the full article will cost you $10.
Now, I have a question for you. Even if this new study is right, what will it change for us? Will you wake up differently tomorrow morning? I don't think so.
The gap between ideals and actualities, between dreams and achievements, the gap that can spur strong men to increased exertions, but can break the spirit of others—this gap is the most conspicuous, continuous land mark in American history. It is conspicuous and continuous not because Americans achieve little, but because they dream grandly. The gap is a standing reproach to Americans; but it marks them off as a special and singularly admirable community among the world’s peoples.
—George F. Will (b. 1941)
Sources: Susan S. Lang, Cornell News Service, June 27, 2005; and various web sites
Related stories can be found in the following categories.
Computers
Medicine
Psychology
Science.