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Language and the ability to communicate is an intrinsic part of being human. All across the globe, in any society, the people will have a shared language from the elderly to the babies still in the cradle. The ability to communicate needs is vital to human survival, and you begin developing language skills before your first birthday. 

The American linguist Noam Chomsky pioneered the theory of Mentalism. Chomsky postulates that humans have an innate ability for language and utterances and that this makes the possibilities within language infinite. Chomsky also believes this biological component of language connects all languages.

Understanding Chomsky’s theory of mentalism is vital for anyone wishing to gain knowledge about human language development. While the subject may seem complex or overwhelming at first, the theory itself is relatively straightforward when you take time to understand it. If you have ever wondered “what is mentalism theory,” keep reading to learn more about Mentalism theory.

Mentalism Theory

The core of Chomsky’s mentalism theory is that speech is a part of human evolution and not purely a learned behavior. He postulates that a genetic mutation approximately 100,000 years ago gave humans an innate ability for language.

He points to the similarities of all languages across history and geographical locations as evidence of this theory. Children’s development of language at the same age and at the same rate no matter the language or society shows it is a biological function more than a social one. 

Almost 70 years after he first introduced his theory to the world, Chomsky’s mentalism theory is still heavily debated. However, despite continued opposition, mainly from proponents of the behavioristic approach to language, the mentalist theory has altered the way language development is viewed and studied. His work continues to raise questions and push boundaries.

Noam Chomsky first introduced the world to his theory of mentalism in his 1957 book Synthetic Structures. He wrote the book as a pushback to the behaviorist theory of language, which he viewed as simplistic and inaccurate. Thus, to understand mentalism, it is also essential to understand the theory of behaviorism and what mentalism is not. 


An opposing theory to mentalism that started in the early 20th century was behaviorism. As the name implies, behaviorism looks at the world through the lens of behavior only and is based on empirical studies of behavior. 

The idea of language as a learned behavior is the fundamental tenet of behaviorism theory. Advocates of this idea claim that children learn a language as they do any other subject, through trial and error and reinforcement from adults. They claim that a child would not develop a language without this guiding hand, and they would remain essentially unable to communicate. 

Behaviorism was a widely held belief in the linguistic community before Chomsky challenged it, with many notable names in science backing the theory. Some of the most famous advocates of behaviorism were:

  • B.F. Skinner
  • John Watson
  • Edward Tolman
  • Ivan Pavlov 

Even now, over a century after the original researchers first put forth these theories, their work still shapes the way language is studied. 


Chomsky believed the opposite; that humans are born with the capacity for speech hard-wired into their biology. He suggested that children will learn a language without someone actively teaching them. As long as a child is exposed to the language on a regular basis simply by people speaking around them, they will develop a language. 

His belief came from childrens’ seemingly natural ability to string words together appropriately without being specifically taught the structure of language. For example, children will instinctively pair a noun with a verb even when they are too young to be taught grammar structures. 

Universal Grammar and the LAD

Chomsky postulated that this natural language creation happens across cultures and history because universal rules govern all human language, and believing otherwise limits language capacity. As language is constantly evolving through slang and artistic uses such as poetry, it stands to reason that its possibilities are limitless.

Linguists have found evidence of this universal grammar by studying several languages and their structural similarities. For example, by using one language and its grammatical structure as a guide, researchers can make accurate predictions about languages that developed on the other side of the world. 

This commonality suggests a genetic component to how people acquire language, which Chomsky named the LAD or Language Acquisition Device. He believed that all people were born with a Language Acquisition Device and that they only needed to be exposed to a language for it to be activated. And within families, this exposure begins almost immediately after birth.

Evidence in Favor of Mentalism

Chomsky pointed to several pieces of evidence as support of his Language Acquisition Device hypothesis. However, at the time, scientists’ understanding of human’s genetic makeup was almost nonexistent. Thus, all of Chomsky’s evidence was based on behavioral and linguistic studies.

Over recent decades, scientists have developed a greater understanding of human behavior and genetics, and in doing so, they have found further evidence to support Chomsky's theory.  

Language Input vs. Output

Typically adults do not speak to infants and toddlers in the same manner as other adults or even older children. When children are first learning to talk, adults give children simple words and phrases such as “more,” “mama,” or “dog.” With this limited input, children develop an entire language, and they do so correctly. 

One of the joys of small children learning to speak is watching them piece together words and expressions independently. Children will make connections and build labels for simple things, but make absolute sense, such as calling their brown cat “cocoa meow” even if no one has explained the correlation between their cats' coat and their favorite drink to them. 

However, science also shows that children require some level of input from their environment to activate the Language Acquisition Device. 

The Language Window

Most people have heard stories of “feral children” who, through horrific circumstances, were left without human interaction during their formative years and did not learn a language. These childrens’ learning and development are closely monitored once they re-enter society as they provide a unique view of language development. 

Through these cases and other studies, scientists have learned that children who do not know a language by the age of 10 will never be truly fluent in any language. In contrast, children who are exposed to multiple languages at a very young age will quickly become multilingual. 

The FOXP2 Gene

Even though much of the human genome is still a mystery, one gene that scientists now know is crucial to speech and communication is the FOXP2 gene. Mutations of this gene are known to cause severe issues with language such as:

  • Inability to move mouth and lips in the ways necessary for speech
  • Trouble stringing words together 
  • Difficulty remembering sounds and syllables 

Researchers hope to better understand humans’ capacity for language through the continued study of this gene and its effects on speech and how it passes within families. 

The Difficulty of Studying Mentalism

While linguists and scientists are continually finding genetic and grammatical evidence to support Chomsky’s theory of mentalism, studying it in a lab with subjects presents some difficulty.  

To effectively study whether children will learn a language without being actively taught, researchers would need to have at least three groups of children:

  • A mentalism group that is only exposed to the language and not directly taught
  • A behaviorism group that is instructed in a language 
  • A control group that is neither exposed to nor taught a language

These requirements present a couple of different issues. First, a behaviorist group would have to be exposed to language only when they were being taught and at no other time. Second, and even more challenging, is the control group, which would require no language exposure, effectively limiting any human contact. 

These limitations on the controlled study of mentalism are why it is essential to monitor the language development of children who have experienced extreme cases of neglect or abandonment. These children are researchers’ only actual window into this type of language deprivation. 


While mentalism is a large and, at times, complex theory of human behavior and development, at its core is a relatively simple idea. The idea that all people are born with the tools needed for speech and language and that these abilities will develop naturally, without structured lessons. And that this genetic predisposition towards language creates a universal connection between all languages. 

Human language development is a complicated and somewhat mysterious process that scientists and linguists struggle to understand. Research has progressed by leaps and bounds in the last century, but complete clarity remains out of reach, and this is a subject that will most likely continue to be debated for decades to come.