Strategic Communications and Marketing News Bureau

Theory: Flexibility is at the heart of human intelligence

CHAMPAIGN, Ill. — Centuries of study have yielded many theories about how the brain gives rise to human intelligence. Some neuroscientists think intelligence springs from a single region or neural network. Others argue that metabolism or the efficiency with which brain cells make use of essential resources are key.

A new theory, published in the journal Trends in Cognitive Sciences, makes the case that the brain’s dynamic properties – how it is wired but also how that wiring shifts in response to changing intellectual demands – are the best predictors of intelligence in the human brain.

“When we say that someone is smart, we understand intuitively what that means,” said University of Illinois psychology professor Aron Barbey, the author of the new paper. “Usually, we’re referring to how good they are at making decisions and solving particular types of problems. But recently in neuroscience, there’s been a focus on understanding in biological terms how general intelligence arises.” That requires studying the structural and functional characteristics of the brain.

Scientists have long understood that the brain is modular, with different regions supporting specific abilities, Barbey said.

“For example, brain regions within the occipital lobe at the back of the brain are known to processes visual information,” he said. But interpreting what one sees requires the integration of information from other brain modules.

 “To identify an object, we also must classify it. That doesn’t depend only on vision. It also requires conceptual knowledge and other aspects of information processing, which are supported by other brain regions,” he said.

Scientists have struggled to understand how the brain organizes itself and have tried to identify a structure or region that performs that function.

“The prefrontal cortex, a structure at the front of the brain, for example, has expanded dramatically over the course of human evolution,” Barbey said. Because this brain region is known to support several higher-order functions such as planning and organizing one’s behavior, scientists have suggested that the prefrontal cortex drives general intelligence.

“But really, the entire brain – its global architecture and the interactions among lower- and higher-level mechanisms – is required for general intelligence,” Barbey said.

Brain modules provide the basic building blocks from which larger, “intrinsic connectivity networks” are constructed, Barbey said. Each network includes multiple brain structures that are activated together when a person engages a particular cognitive skill.

“For example, the frontoparietal network is activated when attention is focused on external cues, the salience network is engaged when attention is directed to relevant events, and the default mode network is recruited when attention is focused internally,” he said.

Neuroscience research on general intelligence has studied two primary facets of intelligence, Barbey said.  

“There are the pathways that encode prior knowledge and experience, which we call ‘crystallized intelligence.’ And there are adaptive reasoning and problem-solving skills that are quite flexible, called ‘fluid intelligence,’” he said.

Crystallized intelligence involves robust connections, the result of months or years of neural traffic on well-worn pathways. Fluid intelligence involves weaker, more transient pathways and connections that are formed when the brain tackles unique or unusual problems.

“Rather than forming permanent connections, we are constantly updating our prior knowledge, and this involves forming new connections,” Barbey said. The more readily the brain forms and reforms its connectivity in response to changing needs, the better it works, he said.

Although researchers have known that flexibility is an important characteristic of human brain function, only recently has the idea emerged that flexibility provides the basis for human intelligence, he said.

“General intelligence requires both the ability to flexibly reach nearby, easy-to-access states – to support crystallized intelligence – but also the ability to adapt and reach difficult-to-access states – to support fluid intelligence,” Barbey said. “What my colleagues and I have come to realize is that general intelligence does not originate from a single brain region or network. Emerging neuroscience evidence instead suggests that intelligence reflects the ability to flexibly transition between network states.”

Barbey directs the Decision Neuroscience Laboratory at the Beckman Institute for Advanced Science and Technology and is affiliated with the Carl R. Woese Institute for Genomic Biology, both at the U. of I.

Editor’s notes:
To reach Aron Barbey, call 217-244-2551; email barbey@illinois.edu.
The paper “Network neuroscience theory of human intelligence” is available from the U. of I. News Bureau.
DOI: 10.1016/j.tics.2017.10.001

Read Next

Life sciences Portrait of the research team posing together.

Minecraft players can now explore whole cells and their contents

CHAMPAIGN, Ill. — Scientists have translated nanoscale experimental and computational data into precise 3D representations of bacteria, yeast and human epithelial, breast and breast cancer cells in Minecraft, a video game that allows players to explore, build and manipulate structures in three dimensions. The innovation will allow researchers and students of all ages to navigate […]

Arts Photo of seven dancers onstage wearing blue tops and orange or yellow flowing skirts. The backdrop is a Persian design.

February Dance includes works experimenting with live music, technology and a ‘sneaker ballet’

CHAMPAIGN, Ill. — The dance department at the University of Illinois Urbana-Champaign will present February Dance 2025: Fast Forward this week at Krannert Center for the Performing Arts. February Dance will be one of the first performances in the newly renovated Colwell Playhouse Theatre since its reopening. The performances are Jan. 30-Feb. 1. Dance professor […]

Honors portraits of four Illinois researchers

Four Illinois researchers receive Presidential Early Career Award

CHAMPAIGN, Ill. — Four researchers at the University of Illinois Urbana-Champaign were named recipients of the Presidential Early Career Award for Scientists and Engineers, the highest honor bestowed by the U.S. government on young professionals at the outset of their independent research careers. The winners this year are health and kinesiology professor Marni Boppart, physics professor Barry Bradlyn, chemical and biomolecular engineering professor Ying […]

Strategic Communications and Marketing News Bureau

507 E. Green St
MC-426
Champaign, IL 61820

Email: stratcom@illinois.edu

Phone (217) 333-5010