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Wed April 11, 2012
Dr. Julio Martinez-Trujillo, McGill University – How the Brain Creates Attention
In today’s Academic Minute, Dr. Julio Martinez-Trujillo of McGill University explains how our brains allow us to focus on more than one thing at a time.
Julio Martinez-Trujillo is an associate professor of psychology at McGill University in Montreal, Canada. His research laboratory is focused on investigating how the brain transforms visual signals into coordinated motor behavior and how this process is influenced by attention. He holds a Ph.D. from the University of Tuebingen, Germany.
Dr. Julio Martinez-Trujillo – How the Brain Creates Attention
Contrary to popular belief, the brain has a limited capacity. It can only process about 1% of the information that the eyes take in. To solve this problem, the brain has evolved the mechanism of attention. Attention is like a filter that allows us to focus on relevant information and discard irrelevant. One question that has puzzled neuroscientists for a long time is how the brain pays attention to multiple objects at the same time.
Do we attend to one thing at a time by rapidly moving a single spotlight of attention back and forth between objects? Do we zoom out the spotlight to include all the relevant objects but also distracters nearby? Or, can we split the spotlight and simultaneously attend to relevant objects while excluding nearby distracters? My team and I set out to solve this controversy.
We recorded the neural activity in two monkeys as they paid attention to two objects on a computer screen. There was also an object in between designed to distract their attention. We found that the monkeys’ brains were able to suppress the distracter and focus on the two targets. This rules out the theory that attention works like a single spotlight zooming around. The speed at which the monkeys perceived a change in the features of the two attended objects, also ruled out the possibility that they were rapidly switching a single spotlight of attention between them. We could only conclude that they split attention into two different spotlights while excluding the distracter.
These results show that the primate brain has evolved to attend to more than one object at a time. We can indeed multi-task! And although finding the limits to splitting attention will require more research, these findings may give us some hints into what causes attentional deficits in some school age children.