Book smarts and life smarts are driven by the exact same intelligence, study finds

For decades, intelligence tests have measured general knowledge by asking questions based on traditional academic subjects. A recent study reveals that information learned through personal life experiences and information learned in a classroom are actually driven by exactly the same underlying mental ability. The research, published in the journal Intelligence, suggests that human knowledge is a deeply unified trait, regardless of the setting in which it is acquired.

Human intelligence is traditionally divided into two broad conceptual categories by psychologists. Fluid intelligence represents the active ability to solve novel problems, adapt to unfamiliar situations, and recognize underlying patterns without relying on prior experience. Crystallized intelligence, on the other hand, refers to the massive accumulation of facts, vocabulary, and practical skills gathered over a person’s lifetime. As people age, their fluid intelligence tends to slowly decline, while their crystallized intelligence continues to grow as they experience more of the world.

Psychologists typically measure this accumulated knowledge through standardized intelligence tests. These assessments historically focus heavily on standard school curriculum subjects, such as world history, mathematics, and classic literature. Many researchers view this as a highly practical way to build a test, because educational curriculums provide a reliable, standardized framework of what people are generally expected to know.

Elisa Altgassen, a psychology researcher at Ulm University in Germany, led the new study alongside Johanna Hartung of the University of Bonn. The researchers suspected that the traditional reliance on academic subjects leaves out a massive portion of the human experience. When tests only measure what people learn in a classroom, they run the risk of underestimating the true breadth of human intellect.

Because people continue learning long after they graduate from formal education, traditional tests might fail to capture the vast amount of information adults pick up through hobbies, career paths, and leisure travel. Adults frequently acquire information in informal, unstructured ways rather than sitting at a desk and listening to a teacher.

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In the world of cognitive psychology, researchers frequently debate how different types of knowledge are stored in the brain. Semantic memory is the functional system responsible for storing general, context-free facts, such as knowing that Paris is the capital of France. Episodic memory relates to specific personal experiences, such as remembering a specific vacation taken to Paris.

Historically, psychologists have wondered if facts learned through personal, real-world experiences are fundamentally different from facts memorized from a chalkboard. Altgassen and her team wanted to figure out if everyday learning could be separated from formal education on a measurable psychological level. They also set out to investigate if natural curiosity drives people to seek out specific life experiences that build worldly knowledge.

To explore these ideas, the researchers designed an experiment featuring 348 adults between the ages of 30 and 40. They deliberately chose this specific age bracket to ensure all participants had enjoyed enough time to gather a wide variety of adult life experiences, while preventing advanced cognitive aging from skewing the final test results. The research team also ensured the participant pool represented a balanced mix of educational backgrounds, matching demographic quotas from the German Federal Statistical Office.

Each person completed a comprehensive online survey. This survey included a standard test of school-based knowledge, featuring 60 questions covering topics typically taught up to the tenth grade in standard educational systems.

The research team also developed a completely new set of 66 questions designed to test knowledge acquired outside of formal education. This second test covered conceptual domains like agriculture, modern technology, and the arts.

Participants then answered a series of yes-or-no biographical questions. Each of these biographical questions was explicitly paired with a specific item on the everyday knowledge test.

For example, a knowledge test question asking for the name of the central processing unit in a computer was paired with a biographical question asking if the participant had ever physically taken apart a desktop computer. Another question asking about a famous architectural landmark in Barcelona was paired with a question about whether the participant had ever visited that specific city.

Finally, the participants filled out psychological questionnaires designed to measure their overall openness to new experiences and their typical levels of intellectual engagement. Intellectual engagement is a personality trait that dictates how much a person enjoys thinking deeply and continuously seeking out new information.

When the researchers analyzed the test results, they found that the scores for school-based knowledge and everyday life knowledge matched up perfectly on a statistical level. The underlying mathematical relationship between the two types of knowledge was incredibly strong, indicating no true separation between them.

This demonstrates that people who perform well on tests of classroom subjects are equally likely to possess a wide array of random facts picked up in their daily lives. The two categories of knowledge do not function as separate mental engines within the brain.

Instead, they reflect a single, unified capacity to gather and recall information. The researchers concluded that the ability to learn is consistent across contexts, whether an individual is sitting in a lecture hall or watching an informative video online.

The study also revealed that a person’s general intellectual curiosity predicted their performance on both kinds of tests equally well. Highly curious individuals tend to absorb more information across the board, demonstrating a consistent drive to figure out how the world works. The researchers originally expected curiosity to play a bigger role in informal learning, working under the assumption that academic environments force all students to digest specific information regardless of their personal interest levels. Instead, the data showed that a natural desire for knowledge yields higher factual retention in both structured and unstructured environments.

However, when examining the data at the individual question level, personal experiences made a tremendous difference. Psychologists study test results by looking at an individual’s general cognitive ability alongside the unique statistical variance tied to specific questions on a test. This unique variance helps researchers isolate exactly why a person might know the answer to one highly specific question but not another of equal difficulty.

If a participant had actually disassembled a computer, they were much more likely to answer the computer hardware question correctly, even after the researchers statistically adjusted for the participant’s overall intelligence level. The statistical ties between specific life events and their corresponding knowledge test items were very strong.

A person’s unique background is directly associated with higher factual retention in specific areas. This suggests that while general intelligence is a unified ability, the specific facts a person holds are heavily shaped by the actual activities they have participated in. Exposure to targeted experiences is linked to a distinct advantage on intelligence test questions related to those experiences.

The study authors noted several limitations to their work. Chiefly, it is inherently difficult to pinpoint exactly where an individual learned any specific fact.

A participant might have learned about a famous painting in a middle school art class, or they might have seen it featured in a television show last week. This blending of educational pathways means the distinction between formal and informal learning is always an approximation and rarely absolute.

The researchers also pointed out that they only surveyed adults in a narrow age bracket in Germany. Different populations might exhibit different learning patterns, heavily dependent on the educational infrastructure and cultural norms of their respective countries. Additionally, it is entirely possible that a lack of knowledge actively motivates people to seek out new experiences, which would complicate the directional relationship between life events and learning.

Moving forward, the research team hopes scientists will track individuals over decades to see exactly when specific life events translate into retained knowledge. The team hopes to eventually refine these kinds of psychological assessments to create fairer intelligence tests that better account for the wildly diverse ways people learn about the world.

The study, “From school lessons to life lessons: School knowledge, life knowledge and their relation to biographical experiences,” was authored by Elisa Altgassen, Johanna Hartung, Diana Steger, Ulrich Schroeders, and Oliver Wilhelm.