Solving the Mysteries of Perception
By LIDA TUNESI
The way our brains use information from our senses to paint a coherent picture of the world is still partly a mystery to scientists.
“When you’re walking around a city, there’s so much sensory information coming into your eyes and ears,” said Professor Tony Ro (The Graduate Center, CUNY). “The question is, what happens to all of that?”
Scientists know that some of this information is processed unconsciously, as Ro and Martijn E. Wokke, a postdoctoral fellow in Ro’s lab, demonstrated in a recent study. This means we can react to information even if we’re not aware we’ve taken it in. Going one step further, the researchers also pinpointed an interaction in the brain that allows this to happen. Their results appear in the Journal of Neuroscience.
The researchers showed volunteers images on a screen and told them to press buttons based on whether the image was tilted to the right or left. Before each image, participants were shown a quick visual cue that indicated how the image would be tilted. As a key to the study, however, the scientists did not tell the participants that these visual cues were, in fact, cues. Only one volunteer figured it out.
Despite not realizing they were getting hints, the volunteers learned from the cues and were able to press the buttons faster as the study went on.
“We found that subjects were not aware of the cues, but the cues were still facilitating these responses,” Ro said. “We found a change in brain activity that was providing a signal that helped guide behavior so responses could be quicker.”
By monitoring the volunteers’ brains with EEG, the researchers discovered an interaction between the prefrontal region and posterior parietal region that is involved in this unconscious processing. According to the paper, the results highlight how important prefrontal processes are in creating our mental, predictive models of our surroundings based on external events.