Intelligence Linked to Whole-Brain Connectivity, New Study Reveals
A new study conducted by neuroscientists at the University of Würzburg (Germany) highlights how communication pathways across the brain can predict intelligence. Unlike previous studies, this research focuses on understanding how the brain’s connectivity relates to intelligence rather than merely predicting test scores. The findings offer a groundbreaking perspective on how intelligence is a global property of the entire brain rather than specific regions alone.
The Study: Methods and Approach
As ScienceDaily reports, the study was led by Jonas Thiele and Dr. Kirsten Hilger, head of the “Networks of Behavior and Cognition” research group at the Department of Psychology I at Julius-Maximilians-Universität Würzburg (JMU). Their research was recently published in the scientific journal PNAS Nexus under the title: “Choosing explanation over performance: Insights from machine learning-based prediction of human intelligence from brain connectivity.”
The research team utilized data from the Human Connectome Project, a large-scale data-sharing initiative based in the United States. This project provided detailed data from over 800 participants, whose brain activity was measured using fMRI (functional magnetic resonance imaging) both at rest and while performing various cognitive tasks.
The study investigated brain connectivity, examining how strongly different brain regions communicate with each other. Using machine learning algorithms, the team made predictions about individual intelligence scores based on these observed connections.
Why Is This Approach Different?
While previous studies have successfully used brain connectivity to predict intelligence scores, these predictions never matched the precision of a standard intelligence test. Instead of focusing on prediction accuracy alone, this research aimed to enhance the conceptual understanding of brain processes behind intelligence. Dr. Kirsten Hilger emphasized the importance of interpretability, urging future studies to follow this direction to better decode human cognition.
Types of Intelligence Explored
The researchers distinguished between three types of intelligence in their analysis:
- Fluid Intelligence: The ability to solve new problems, process information, and recognize patterns without relying on prior knowledge. Example: Solving a puzzle you’ve never seen before.
- Crystallized Intelligence: The accumulation of knowledge, skills, and experience acquired over a lifetime. Example: Understanding historical facts or using vocabulary learned through education.
- General Intelligence: A combination of fluid and crystallized intelligence, representing overall cognitive ability.
The study revealed that general intelligence was the most predictable, followed by crystallized and fluid intelligence.
Key Innovations of the Study
This study introduces several innovations that distinguish it from previous research on intelligence:
- Focus on Conceptual Understanding: Unlike earlier studies, which prioritized prediction accuracy, this study emphasizes interpreting the brain’s connectivity patterns to understand intelligence.
- Machine Learning Application: The team used machine learning to analyze massive data sets and uncover patterns that might otherwise remain undetected.
- Whole-Brain Analysis: While most established theories focus on specific brain areas (e.g., the prefrontal cortex), this study reveals that intelligence emerges from connections across the entire brain.
- Testing Random Connections: By comparing both theoretically important and randomly selected brain connections, the researchers demonstrated that the sheer number and distribution of connections matter more than their exact location.
- Complementary Connections: The study found that adding connections beyond the traditionally studied regions improves predictive performance, suggesting a broader neural basis for intelligence.
Key Findings: Intelligence Is a Global Property of the Brain
The research yielded several crucial conclusions about the relationship between brain connectivity and intelligence:
- Whole-Brain Connectivity Predicts Intelligence:
- Intelligence relies on connections distributed throughout the brain, not just a few key regions. Example: Like a well-functioning computer network, the brain’s overall connectivity is more important than individual “nodes” (regions).
- Number of Connections Matters:
- The more connections present across the brain, the better the predictive performance for intelligence scores. Example: Think of intelligence as a city’s transportation system—the more roads connecting neighborhoods, the smoother the flow of people (or, in this case, information).
- Random Connections Still Contribute:
- Surprisingly, even randomly selected brain connections predicted intelligence, underscoring the global nature of intelligence.
- General Intelligence Is Most Predictable:
- Combining fluid and crystallized intelligence (general intelligence) produced the best results, highlighting its comprehensive nature.
- Established Theories Are Incomplete:
- While traditional neurocognitive models perform well, the study revealed that adding complementary connections further improves predictions. Intelligence involves far more areas than previously assumed, like discovering additional branches on an already complex tree.
Cognitive Abilities and Brain Connectivity
The study’s findings highlight how brain connectivity underpins key cognitive abilities. For instance:
- Fluid Intelligence allows us to adapt to new challenges, such as solving unfamiliar problems or learning new skills quickly.
- Crystallized Intelligence supports language comprehension, long-term memory, and decision-making, which depend on accumulated knowledge.
The whole-brain connectivity approach suggests that intelligence is a result of efficient communication pathways that span multiple brain regions, enabling faster and more effective processing of information.
The Importance of Cognitive Training
The findings emphasize that intelligence depends on overall brain connectivity, which cognitive training can help strengthen. Cognitive training includes targeted exercises designed to improve specific mental processes like memory, reasoning, and problem-solving.
How Cognitive Training Enhances Brain Connectivity:
- Neuroplasticity: The brain’s ability to adapt and form new connections improves with regular mental stimulation. For example, solving logic puzzles or learning a new language enhances fluid intelligence.
- Improved Communication Pathways: Cognitive exercises like memory games, reasoning tasks, or mindfulness techniques can help strengthen communication between brain regions.
- Crystallized Knowledge Growth: Activities like reading, attending lectures, or acquiring new skills expand crystallized intelligence and create stronger neural connections over time.
- Consistency matters: Just as physical exercise builds muscles, consistent cognitive training can help to gradually improve the overall efficiency of the brain.
- Long-term benefits: It has been proven that cognitive training can help slow cognitive decline and improve mental performance at any age.
If you want to measure your fluid intelligence, the IQbe CogniFit Intelligence Test offers a reliable way to assess your IQ score through scientifically validated tasks. By encouraging cognitive training programs, individuals can actively work toward improving their brain’s connectivity, enhancing their problem-solving abilities and long-term cognitive health.
Significance for Science, Medicine, and Society
The findings of this study have profound implications across various fields:
- Science: Provides a deeper understanding of how brain connectivity contributes to intelligence, advancing neuroscience research.
- Medicine: Insights into brain-wide connectivity may help identify and address cognitive impairments in neurological disorders such as Alzheimer’s disease, where communication pathways are disrupted.
- Education: A better understanding of general intelligence could inform teaching methods that optimize cognitive development by strengthening brain connectivity through targeted learning strategies.
- Society: Encourages a shift from viewing intelligence as the function of isolated brain areas to a more holistic perspective, promoting cognitive training programs that enhance whole-brain communication.
Conclusion
The groundbreaking study led by researchers from the University of Würzburg challenges traditional views of intelligence by demonstrating that it is a global property of the entire brain. Through the innovative use of machine learning and fMRI data, the team has shown that brain-wide connectivity—not just isolated regions—predicts intelligence.
This research not only enhances our understanding of the brain but also opens new pathways for studying and improving cognitive abilities in science, medicine, and education. As Dr. Kirsten Hilger notes, focusing on the interpretability of results is the key to uncovering the intricate neural code behind human intelligence. Future studies will no doubt build on these insights to further unravel the mysteries of our most complex organ: the brain.
