The Swiss Army Knife Theory: Modularity of the Mind

· February 19, 2019
The Swiss army knife theory states that the mind is divided in modules which are specialized in specific activities and help the brain solve problems in determined areas.

The Swiss army knife theory is a controversial but curious explanation of how the mind works. According to this modular approach, our brain is composed of highly specialized “applications” to solve specific problems in the most effective way. Thus, our mind is a combination of specific areas or tools, just like the Swiss Army knife.

This idea was originally presented in 1992 by anthropologist John Tooby and psychologist Leda Cosmides. It’s worth noting that this perspective, as well as the concept of modularity to explain perceptive and cognitive processes, is highly criticized by neuroscience experts.

Philosopher Jerry A. Fodor spent his whole life studying the human cognitive structure. He was an expert in linguistics, logic, semiotics, psychology, computer science, and artificial intelligence. One of his most relevant pieces of work was Modularity of Mind, which was published in 1983.

“We’ve got lots to do. In fact, what our cognitive science has done so far is mostly to throw some light on how much dark there is.”

-Jerry A. Fodor-

Mechanism of a child's mind.

The Swiss Army knife theory

The Swiss Army knife theory has an aspect all experts can agree on. Dr. Fodor pointed out that the brain, as a physical and observable entity, is becoming easier to study thanks to technological advances. However, there’s a point where the study of the mind enters another more abstract and imprecise level where technology loses its value.

This theory, which is half-way between philosophy and psychology, is a particular way of defining and explaining our cognitive processes.

Let’s delve deeper into the principles that define the Swiss Army knife theory.

Mental modules

In 1950, linguist and philosopher Noam Chomsky started defending one of his most renowned theories: that language isn’t a learned behavior but a functional and innate faculty. This premise later inspired Dr. Fodor.

  • He was also inspired by Turing’s work on mathematical computer models. Little by little, he created the foundation of his approach that states that the mind is divided into specialized modules.
  • He called them “the psychological faculties”. Thus, each process of your mind is divided into different specialized modules, like unique programs on a computer. Thus, there’s a module for sensation and perception, another one for volition, another for memory, and another one for language.

The supporters of the Swiss Army knife theory

Jerry A. Fodor published his theories in his book Modularity of Mind (1983). Later, Doctors Tooby and Cosmides defined the Swiss Army knife theory based on Fodor’s work.

Although this theory is controversial, many scientists still defend it. Nancy Kanwisher, professor and researcher at the MIT Department of Brain and Cognitive Sciences, supports this theory.

One of her most popular TED talks took place in 2014. During this talk, she explained the validity of the Swiss Army knife theory. In fact, she carried out several scientific studies that support the idea. They were published in the Journal of Neuroscience. 


Something that Dr. Kanwisher observed through MRIs is that many brain areas don’t communicate with each other. Thus, they work in an isolated manner.

An example is prosopagnosia, which is a condition where the sufferer sees perfectly but isn’t able to recognize people. Thus, they’re able to see their children but are unable to recognize them when they pick them up from school.

This theory states that many specialized areas of the brain work as modules, such as those that process color, shapes, movement, and speech.

Criticism of the modular mind theory

Many people see this as a simplistic approach in which natural selection isn’t ruled out. This perspective states that our behavior is like a program we acquire as time passes. Thus, each process or function develops and specializes independently from the rest.

Studies such as the one published in the PLOS Biology journal point out the risk of accepting the modular theory because the brain isn’t a fragmented entity. It’s much more complicated than that.

In spite of the fact that certain areas of the brain don’t communicate with each other, the brain doesn’t work through different specialized and separate sections. The brain is designed to share information and work as one entity.

We use different concepts, inferences, processes, and inductions. Therefore, we’re much more complicated, fascinating and unpredictable.