Why You Dial A Phone The Way You Do: Your Brain Makes Information Chunks

Ever notice how you dial a phone? The first time you dial a number, you do it one number at a time, pausing to make sure that each sequential movement is entered correctly. Eventually, the series of finger movements becomes more rapid, and occurs in bursts. First three for the area code, next three, and finally, the last four numbers. Scientists at the University of California, Santa Barbara were intrigued by this 'parsing' of information, and their new study shows details of how this occurs in our brains.

"You can think about a chunk as a rhythm," said Nicholas Wymbs, a postdoctoral researcher in UC Santa Barbara's Department of Psychological and Brain Sciences, and the lead author of a new study on motor chunking in the journal Neuron, published by Cell Press. "We highlight the two-part process that seems to occur when we are chunking. This is demonstrated by the rhythm we use when typing the phone number: rapid bursts of finger movements that are interspersed by pauses."

The brain does this, according to Wymbs, because it is an efficient way to sequence long sequences of movement. Once the brain becomes familiar with the series of movements, it tries to figure out the most efficient way to carry them out, with as little effort as possible. By breaking up the sequence into fluid chunks, the brain is attempting to maximize efficiency.

Any repetitive task such as dialing, texting, typing, and playing a musical piece evokes this kind of response.

"Initially, when you're doing one of these 12-element sequences, you want to pause," said Wymbs. "That would evoke more of the parsing mechanism. But then, over time, as you learn a sequence so that it becomes more automatic, and the concatenation process takes over and it wants to put all of these individual elements into a single fluid behavior."

By observing the study's participants, the researchers found that when first learning a series of movements, the putamen region of the brain is dominant. The putamen is critical to movement. After a while, however, the cortical regions of the left hemisphere became more active in the process, indicating a shift in the way our brain is interpreting the information.