Adults’ high cognitive abilities usually predict intuition accurately, but this mental shortcut takes time to develop. A new study of middle school and high school students reveals that young people rely heavily on slow, deliberate thinking to solve logical puzzles, before correct intuition has fully matured. The study was recently published in the journal Thinking & Reasoning.
Psychologists often divide human thinking into two different categories based on speed and effort. The first type of thinking is fast, automatic, and requires little mental energy. The second type is time consuming, careful, and requires continued attention to detail.
For decades, researchers have believed that successfully solving math and logic puzzles always requires a second, slower type of thinking. In this traditional view, our quick assumptions are often biased and flawed. To reach a mathematically correct conclusion, a person must actively block his immediate instincts and spend time calculating the correct answer.
Recent research on adult reasoning challenges this assumption. Scientists have discovered that many adults can give correct and logical answers almost instantly. You don’t have to stop and think slowly to solve basic probability problems.
This phenomenon is often associated with general intelligence. Adults who score high on cognitive ability tests tend to have accurate first instincts. This match of intelligence and instant accuracy has led researchers to call them “smart intuitives.”
A team of psychology researchers wanted to know exactly when this precise intuition develops. Lead author Laura Charvit and colleagues at the University of Paris-Cité in France designed an experiment to test reasoning abilities across adolescence. They wanted to see if middle school and high school students already exhibited the mature profile seen in adults.
The research team recruited more than 300 students from French secondary schools. Approximately half of the participants were in seventh grade, with an average age of approximately 12 years. The other half were 12th graders nearing the end of their secondary education, with an average age of about 17 years.
To measure how the students thought, the researchers gave them a series of probability puzzles. Puzzles are designed to create contradictions between statistical facts and appealing stereotypes. For example, participants read about a study involving 995 accountants and 5 clowns.
Students were then asked to guess the occupation of a randomly selected person from the study labeled Person L. The prompt described Person L with one word: “Interesting.” Based on the clown stereotype, a quick and appealing answer is to assume that person L is a clown.
However, mathematically, you’re more likely to get a different answer. There are 199 times more accountants than clowns in a group, so even if they have a sense of humor, a random person is far more likely to be an accountant. To arrive at this correct answer, you need to pay attention to baseline statistics rather than descriptive personality traits.
To distinguish between quick intuition and slow deliberation, the researchers used a special test format. In the first part of the exam, students had to answer within 3 seconds. To make deep thinking even more challenging, students had to memorize a grid of symbols before reading the puzzle.
This memory work occupied their active attention, forcing them to rely on pure instinct for their initial reactions. Students answered quickly and remembered the grid, then looked at the puzzle again. During this second stage, they were given unlimited time to think and could change their original answers if they wished.
The researchers also included a control puzzle in which both the personality description and the statistics indicated exactly the same answer. Both age groups performed extremely well on these control puzzles, demonstrating that they were paying attention to the wording rather than just guessing at random. Finally, the students took a standardized test designed to measure general cognitive abilities using complex visual patterns.
Looking at the results, the researchers found clear differences between the age groups. During the quick, instinctual phase of the test, older adolescents gave more mathematically correct answers than younger adolescents. Under conditions of extreme time pressure and distraction, older students were able to make better use of statistical numbers rather than fall into a fixed mindset.
Giving students time to think also produced different results depending on their age. Grade 12 students improved their scores because they were given unlimited time to review the puzzles. The extra time allowed them to realize their mistakes and switch from formulaic to mathematical answers.
Seventh graders did not experience the same benefits. Their scores remained relatively flat between the fast and slow phases of the experiment. Extra time spent thinking about the problem did not lead the young students to a statistically correct answer.
The lack of progress for younger students at later stages is particularly instructive. This suggests that they do not yet have the basic mental strategies necessary to overturn basic stereotypes. Even if they have endless amounts of time to think about numbers, the adolescent brain defaults to preferring explanatory stories.
The researchers also took a closer look at how general cognitive abilities relate to puzzle performance. For older teens, higher cognitive ability scores predicted certain behaviors. Smart 12th graders were most likely to use the extra time to correct their initial incorrect intuition.
Unlike adults, older teenagers’ cognitive ability scores were not strongly associated with having the right early instincts. This means that the immediate problem-solving skills found in adulthood are not fully matured by the time they graduate from high school. Older teenagers still rely heavily on their intelligence to facilitate slow, deliberate correction.
For seventh graders, cognitive ability scores did not predict accurate puzzle performance at all. The smartest adolescents in the young group did not significantly outperform their peers in either the fast or slow stages of the test. In this young age group, the relationship between cognitive ability and accurate reasoning was not statistically significant.
The study authors suggest that these results indicate a gradual optimization of logical rules. When children first learn about fractions and probability, applying these concepts requires intense mental effort. As they progress through middle school and high school, they receive thousands of hours of study practice.
With prolonged exposure, the rules of logic eventually become second nature. By 12th grade, students begin to internalize these concepts and their intuition improves slightly. However, the transition is still underway.
The instantaneous and seamless translation of advanced cognitive abilities into error-free logic seems to be a feature of adulthood rather than adolescence. This study has several limitations that leave room for future exploration.
Researchers initially included a second type of logic puzzle, the famous bat and ball problem. Participants are told that the bat and ball together cost a certain amount of money, and that the bat costs exactly one dollar more than the ball. This puzzle proved to be frustratingly difficult for both age groups, with too few correct answers to analyze properly.
Future experiments will need to include a wider variety of reasoning questions to confirm this educational trend. Researchers may also benefit from testing these specific cognitive thresholds across different cultures and school systems.
The ability to generate quick and rational answers does not develop overnight. This research shows that sound judgment is a skill that is developed slowly over years of education and life experience.
The study, “The Emergence of the Wise Intuitor: How Cognitive Abilities Shape Adolescent Reasoning,” was authored by Laura Charbit, Esther Boissin, Matthieu Raoelison, and Wim De Neys.
