The ability to connect new information and solve entirely new problems are mutually reinforced as children grow. Researchers who followed elementary school students for three years found that improved learning relevance predicted subsequent improvements in reasoning ability, and vice versa. These results were published in the journal intelligenceindicating that these two basic cognitive abilities do not function strictly in isolation but develop in tandem.
Associative learning is a mental process of forming connections between different pieces of information. Remembering people’s names by associating them with faces, and matching vocabulary to their basic definitions, rely on this process. Experiencing these connections allows people to organize scattered input into useful, structured knowledge. In the classroom, associative learning forms the basis for basic memorization, sequential recognition, and early concept formation.
Fluid intelligence requires a distinctly different set of mental tools. This refers to a person’s ability to think abstractly, adapt to unfamiliar situations, and solve new problems. Fluid intelligence requires the brain to analyze new patterns in real time, rather than relying heavily on prior knowledge or facts memorized from textbooks. Both mental processes mature significantly during late childhood, setting the stage for lifelong academic achievement.
Previous psychological theories debated how exactly these two attributes interact throughout a child’s life. Some early models proposed that fluid intelligence serves as an innate baseline tool that individuals apply to learn new associations. In this perspective, high innate reasoning abilities enable students to detect patterns and gather knowledge at an accelerated pace. These theorists argued that fluid intelligence serves as the primary investment engine that drives educational success.
Other theorists suggested quite the opposite direction of growth. They proposed that overall problem-solving ability is slowly built through a continuous process of learning combinations and patterns. Under this framework, children who have active and effortful learning experiences gradually build the flexible thinking skills necessary for advanced reasoning. By continually practicing new associations, children develop cognitive flexibility over time until abstract problem solving feels more natural.
Recent developmental frameworks view the brain as a highly active interconnected network. Under these mutualistic models, distinct cognitive abilities such as memory and reasoning do not develop in isolation. These have long been thought to reinforce each other, and breakthroughs in learning efficiency may trigger subsequent improvements in the analysis of complex patterns.
To test these developmental models in real time, Xuezhu Ren, an education researcher at Huazhong University of Science and Technology in Wuhan, China, and a team of colleagues conducted a multi-year follow-up study of elementary school students. The researchers wanted to see whether superior performance in associative learning positively predicted subsequent improvement in reasoning ability. They also wanted to measure whether early reasoning ability predicted subsequent improvements in associative learning.
The study followed 160 fourth graders in China. The team assessed the children at three different time points, with each testing session separated by exactly 12 months. Scientists tracked students from fourth to sixth grade to capture key periods of cognitive development.
To measure associative learning, the researchers used a computer-based test. The team introduced the children to a set of abstract graphics, each mapped to a specific letter followed by a secondary graphic. After practicing these chains of associations, the children had to find the correct combination of three parts from a lineup of incorrect choices.
To measure fluid intelligence, researchers administered two standard reasoning tests. In one test, children were asked to look at progressive geometric patterns that included missing puzzle pieces. Students had to determine the hidden rules of the pattern and choose the correct shape to complete the sequence. Another test presented a string of numbers or letters that followed a certain logical progression and challenged students to find a single item that violated the rule.
The team also assessed students’ working memory and processing speed at the beginning of the study. Working memory acts as a notepad for the mind, allowing people to retain and manipulate short-term information. Processing speed measures how quickly your brain can recognize and respond to simple visual cues. The team wanted to make sure that the relationship between learning and problem-solving was not just a side effect of a naturally faster or larger mental working space.
To assess working memory, students completed a visuospatial task in which they memorized the location of a flashing red square on a grid. They also completed a direction-based task that required them to suppress their natural reflexes. To measure processing speed, children completed a visual task in fast forward that required them to decide which side of a grid contained more points or triangles.
At a general level, researchers found that students who scored high on association tasks also tended to score high on inference tasks. Across groups, a stable positive correlation existed between the two different skills. To understand how each particular child’s abilities develop, the researchers used a statistical model that separates overall population trends from individual growth curves.
By tracking each child against their own baseline performance, the team discovered mutual growth effects. If children performed better than their own expected baseline in associative learning one year, they tended to show greater-than-expected gains in fluid intelligence the following year. This pattern suggests that practice with associative links laid the foundation for better abstract reasoning.
The opposite development path was also evident. Children who experienced a spike in fluid intelligence scored higher than expected on associative memory tests the following year. The researchers observed no statistical evidence that one direction was overwhelmingly stronger than the other. The two skills seemed to feed each other equally over the three years.
These reciprocal patterns remained stable even when the statistical model subtracted students’ baseline working memory and processing speed. The relationship between association formation and abstract reasoning appears to exist as a dedicated connection, rather than simply a product of general brain speed. Associative learning involves the formation and stabilization of new relational structures, which is fundamentally different from short-term maintenance obligations processed by working memory.
The authors suspect that both skills share underlying mental mechanisms. For example, both tasks require the ability to focus on relevant rules while successfully blocking out distracting information. Strong reasoning skills may also enable children to devise better logical strategies for memorizing combinations, rather than relying on memorization and repetition.
Although researchers have documented clear correlations, they cannot claim strict causation. Because this study is based on observing test scores over time, it is impossible to say with absolute certainty that improvements in one skill directly lead to improvements in the other. In future test settings, scientists may conduct controlled experiments to see whether certain instructional routines aimed at promoting associative learning positively improve scores on fluid reasoning tests.
This study was characterized by a relatively small sample size. Assessing these developmental markers required intensive one-on-one administration with each child, limiting broader participant numbers. Also, this study only focused on children in late elementary school, and younger and older age groups were excluded from the dataset.
Tracking students across a broader age range may reveal whether these mutual benefits remain stable and persistent throughout childhood and adolescence. The specific task used at the first test point also showed poor internal reliability, which may have suppressed some of the initial data patterns. If cognitive skills truly develop in parallel, then school curricula that balance memory-building tasks with problem-solving tasks may foster broader intellectual growth in students.
The study, “More than correlation: Longitudinal evidence of bidirectional effects between associative learning and fluid intelligence in elementary school students,” was authored by Xuezhu Ren, Shaochun Zhao, Xinyu Huang, and Xiaojing Lv.
