Summary: A new study investigates what happens when we multitask and why it’s not such a good idea to drive and use a phone at the same time.
Source: Linköping University.
When we are busy with something that requires the use of sight, the brain reduces hearing to make it easy for us. This is the conclusion of a study conducted by researchers from Linköping University in collaboration with others. The results give researchers a deeper understanding of what happens in the brain when we concentrate on something.
“The brain is really clever, and helps us to concentrate on what we need to do. At the same time, it screens out distractions that are extraneous to the task. But the brain can’t cope with too many tasks: only one sense at a time can perform at its peak. This is why it’s not a good idea to talk on the phone while driving,” says Jerker Rönnberg of Linköping University, professor of psychology with a focus on disability research.
He and his colleagues have investigated what happens in our brains when we are occupied by a visual task. One example is a student is taking an exam, while another is a person driving a car. The researchers also wanted to see how concentration changes when the background noise increases.
Thirty-two students from Linköping University took part in the study, which has been published in the journal Frontiers in Human Neuroscience. The students were given a visual task to work on, some of them in calm surroundings and others with distracting background noise. Images of their brains were taken with an fMRI camera while they worked. The researchers also tested the function of the students’ short-term memory using a memory test with letters.
The results show that brain activity in the auditory cortex continues without any problems, as long as we are subjected to sound alone. But when the brain instead is given a visual task, such as a written exam, the response of the nerves in the auditory cortex decreases, and hearing becomes impaired. As the difficulty of the task increases, the nerves’ response to sound decreases even further. A high cognitive load in the form of a visual task thus impairs the brain’s response to sound not only in the cortex, but also in the parts of the brain that deal with emotions. This is information that is not involved with solving the task.
“This is basic research into how the brain works, and the results suggest many possible paths for further work. The knowledge gained may be important in the future design of hearing aids. Another possibility is that our research will form the basis for work looking into how impaired hearing influences the way in which we solve visual tasks,” says Jerker Rönnberg.
Others who have participated in the work are Patrik Sörqvist, at the University of Gävle, and Örjan Dahlström and Thomas Karlsson from Linköping University.
Funding: The project has been funded by Riksbankens jubileumsfond (the Bank of Sweden Tercentenary Foundation) and the Swedish Research Council.
Source: Anna Nilsen – Linköping University
Image Source: NeuroscienceNews.com images are adapted from the Linköping University press release.
Original Research: Full open access research for “Concentration: The Neural Underpinnings of How Cognitive Load Shields Against Distraction” by Patrik Sörqvist, Örjan Dahlström, Thomas Karlsson and Jerker Rönnberg in Frontiers in Human Neuroscience. Published online May 18 2016 doi:10.3389/fnhum.2016.00221
Concentration: The Neural Underpinnings of How Cognitive Load Shields Against Distraction
Whether cognitive load—and other aspects of task difficulty—increases or decreases distractibility is subject of much debate in contemporary psychology. One camp argues that cognitive load usurps executive resources, which otherwise could be used for attentional control, and therefore cognitive load increases distraction. The other camp argues that cognitive load demands high levels of concentration (focal-task engagement), which suppresses peripheral processing and therefore decreases distraction. In this article, we employed an functional magnetic resonance imaging (fMRI) protocol to explore whether higher cognitive load in a visually-presented task suppresses task-irrelevant auditory processing in cortical and subcortical areas. The results show that selectively attending to an auditory stimulus facilitates its neural processing in the auditory cortex, and switching the locus-of-attention to the visual modality decreases the neural response in the auditory cortex. When the cognitive load of the task presented in the visual modality increases, the neural response to the auditory stimulus is further suppressed, along with increased activity in networks related to effortful attention. Taken together, the results suggest that higher cognitive load decreases peripheral processing of task-irrelevant information—which decreases distractibility—as a side effect of the increased activity in a focused-attention network.
“Concentration: The Neural Underpinnings of How Cognitive Load Shields Against Distraction” by Zoya J.R. Bastany, Shahbaz Askari, Guy A. Dumont, Erwin-Josef Speckmann, and Ali Gorji in Neuroscience. Published online July 7 2016 doi:10.3389/fnhum.2016.00221