Do Intelligent People Think Faster?
Scientists at the Berlin Institute of Health at Charité (BIH) and the Department of Neurology and Experimental Neurology of Charité—Universitätsmedizin Berlin, together with a colleague from Barcelona, have made a startling discovery about decision-making speed. The researchers found that participants with higher intelligence scores were only quicker when tackling simple tasks, while they took longer to solve difficult problems than subjects with lower IQ scores.
Personalized brain simulations
The research was based on personalized brain simulations of the 650 participants of the Human Connectome Project, a U.S. initiative that has been studying neural connections in the human brain since September 2010. To simulate the mechanisms of the human brain, the team used digital data from brain scans like magnetic resonance imaging (MRI) as well as mathematical models based on theoretical knowledge about biological processes.
For the present study, the scientists refined this general model using data from individual people, thus creating personalized brain models. They knew how participants fared on extensive cognitive tests and what their IQ scores were.
Excitation-inhibition balance in neurons
“It’s the right excitation-inhibition balance of neurons that influences decision-making and more or less enables a person to solve problems,” explains Prof. Petra Ritter, head of the Brain Simulation Section at the BIH.
In the model, a so-called winner-take-all competition occurs between different neural groups involved in a decision, with the neural groups for which there is stronger evidence prevailing. Yet in the case of complex decisions, such evidence is often not clear enough for quick decision-making, literally forcing the neural groups to jump to conclusions.
Reduced functional connectivity
The models revealed how reduced temporal coordination results in the information required for decision-making neither being available when needed nor stored in working memory. Resting-state functional MRI scans showed that slower solvers had higher average functional connectivity, or temporal synchrony, between their brain regions.
In personalized brain simulations of the 650 participants, the researchers could determine that brains with reduced functional connectivity literally “jump to conclusions” when making decisions, rather than waiting until upstream brain regions could complete the processing steps needed to solve the problem.
Gathering evidence takes time—and leads to correct decisions
“Synchronization, i.e., the formation of functional networks in the brain, alters the properties of working memory and thus the ability to ‘endure’ prolonged periods without a decision,” explains Michael Schirner, lead author of the study and a scientist in Ritter’s lab.
“In more challenging tasks, you have to store previous progress in working memory while you explore other solution paths and then integrate these into each other. This gathering of evidence for a particular solution may sometimes take longer, but it also leads to better results.
Medical applications of the findings
Ritter is pleased that the results observed in the computer-based “brain avatars” match the results seen in “real” healthy subjects. Her main interest is in helping patients affected by neurodegenerative diseases like dementia and Parkinson’s disease.
“The simulation technology used in this study has made significant strides, and can be used to improve personalized in silico planning of surgical and drug interventions as well as therapeutic brain stimulation.
“For example, a physician can already use a computer simulation to assess which intervention or drug might work best for a particular patient and would have the fewest side effects.”
Summary of Findings
The researchers at the BIH and Charité—Universitätsmedizin Berlin, together with a colleague from Barcelona, discovered that participants with higher intelligence scores were only quicker when tackling simple tasks, while they took longer to solve difficult problems than subjects with lower IQ scores. The research was based on personalized brain simulations of the 650 participants of the Human Connectome Project, and they found brains with reduced functional connectivity literally “jump to conclusions” when making decisions, rather than waiting until upstream brain regions could complete the processing steps needed to solve the problem. Resting-state functional MRI scans showed that slower solvers had higher average functional connectivity, or temporal synchrony, between their brain regions.
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