The human brain is a mystery (which it somehow knows, seeing as how it’s guiding these very words), but scientists at the University of Buffalo believe their study definitively settles an age-old debate in cognitive science circles: The brain definitely uses two distinct systems to process learned information.

For many decades, theories of brain behavior claimed only one system was at work for all neural processing. When we first learned how to ride a bike, in between the wobbles and scrapes, our brains were laying specific architecture. When we started learning about the world at large, our brains got to work again. The lessons got filed away deep in the neurons responsible for learning, and now Buffalo researchers claim the specific location of each is entirely different.

Implicit vs. Explicit

The two systems are often referred to as implicit and explicit learning. An easy example is buying a pair of sneakers. Your implicit learning system has developed over the years to tell you that certain brands, styles, and prices are more or less “normal.” You have a fairly good idea of what kind of shoes you would and wouldn’t buy.

But the thing is, you aren’t acknowledging these opinions consciously. Your implicit learning system has internalized the sense of normalcy to such an extent that it’s just the way. It feels right.

Meanwhile, your explicit learning system wants to act rationally as best it can. You shop around online, try out various sizes and styles, ultimately hoping to find the exact pair of sneakers you think fit your needs and wants. Eventually you end up purchasing some, and you’re happy with your decision. But how can you know whether your purchase was the result of calculated decision-making or years of engrained preferences that have been molded over time?

To tease out the two forms of learning, Smith and his colleagues administered a type of test that students face on a regular basis. They were asked to perform various tasks and given no corrective feedback until the very end — much like a final score on an exam. Because the method doesn’t give moment-to-moment feedback, meant to help the students self-correct as they go, they can’t use their implicit learning systems. They receive no stimulus to associate with their behavior, Smith says.

“Our finding that there are distinct, discrete systems has implications for the fields of child development and cognitive aging,” said lead researcher, cognitive psychologist Dr. J. David Smith, in a news release. The theory goes that if researchers can develop a picture of both cognitive systems robust enough to map individual learning patterns, for both child development and cognitive aging, children and the elderly would enjoy tailored modes of learning.

Where Both Systems Can Go

To answer the sneaker question: The truth is, you can’t know which system is at work. It’s a misguided question from the start, the researchers assert. Both processes are working simultaneously to create a mish mash of preferences and ideals that you’re both consciously aware of and psychologically oblivious to.

“Because of the considerable controversy surrounding the question of whether we have more than one cognitive system, researchers have continued to seek models that distinguish the processes of explicit and implicit category learning,” Smith said, “and this study presents the clearest distinction yet found between these systems.”

The researchers were able to “unplug” the implicit learning system, “but leave the explicit-conscious system functioning and intact,” thus forcing subjects to rely on their explicit learning strategies. As a result, their corrective ability suffered.

Recall the math tests you took in high school. When you reached a problem you couldn’t quickly solve, how did you try to solve it? If you’re anything like Smith’s subjects, you either pulled a strategy out of left field or you gave up. And according to Smith, that fact is telling.

“In the area of categorization research, the issue of single vs. multiple systems is nearly closed. The evidence is now very strong that there are multiple category-learning systems — in particular, the explicit-conscious and the implicit-procedural system.”

The next step in researching each system is gaining a better understanding of where clinical help comes in. If senior citizens on the brink of dementia could somehow tap into their implicit learning systems, perhaps their brains would remain intact for longer. Similarly, if parents had the ability to understand when and how their children learn basic tasks, they could style their education to fit each child — bookending, in effect, the human experience based only on the three-pound master between your ears.


Source: Smith J, Boomer J, Zakrzewski A, et al. Deferred Feedback Sharply Dissociates Implicit and Explicit Category Learning. Psychological Science. 2014.