Mental lexicon

Mental lexicon is the personalized system of language storage and retrieval that an individual uses to be able to recognize and find words. Acting like the brain’s dictionary, a mental lexicon includes everything a person knows about a word, such as how it sounds, what it means, which words are its synonyms, and which words are its antonyms. A mental lexicon is individualized because it is based on a person’s own experiences with words, the language or languages the person understands, the culture in which they live. Researchers understand what a lexicon is and what it does. However, they are still trying to unravel the process by which the brain creates a system that can retrieve words in fractions of a second and the variables that affect how the brain stores and retrieves words.

Background

The ability to communicate with words strung together to form complex thoughts in endless combinations is a uniquely human trait. It is a common behavior that begins in infancy and is usually fully present by the age of five. However, experts have long debated how this ability is formed.

One of the earliest theories was that it was a learned behavior encouraged by repetition and reinforcement. American behavioral psychologist B.F. Skinner (1904–1990) suggested that if a child hears a word and sees the object the word represents several times, the child will make an association. The child repeats the word or an approximation of it and is rewarded in some way, which reinforces the connection. For example, a child sees a round object rolling on the ground. A parent says, “Here comes the ball!” and the child repeats, “ball!” The parent reinforces this by smiling and handing the child the ball.

Others pointed out that while this theory accounts for how a child learns the meaning of some words, it does not fully address how children learn to string individual words together to form phrases and sentences. American linguist Noam Chomsky (1928– ) suggested that people have a universal grammar built into them that helps them categorize words and understand how they fit into language patterns. Chomsky said this explains why even young children automatically know how to correctly combine nouns and verbs, such as “Mommy go.”

Still later research disputed the idea that grammar could be biologically programmed. Instead, they proposed that children learn language by decoding the patterns in the language they hear spoken around them. According to this theory, even before children have the mental sophistication needed to understand why they are using a specific language construct, such as adding an “s” to make a word plural, they have discerned the pattern, internalized it, and used it. This explanation addresses why children make certain grammatical errors, such as saying “mouses” instead of “mice.”

Overview

“Lexicon” is a Greek word that literally means a collection of words or dictionary. It originated from the Greek lexis, meaning “word,” and came into English usage in the seventeenth century. In 1966, author R.C. Oldfield used the term “mental lexicon” in the article “Things, Words, and the Brain,” published in the Quarterly Journal of Experimental Psychology.

A mental lexicon is like the brain’s dictionary because it has all the elements of a dictionary. This includes how the word is pronounced, what it means, alternate or additional meanings, synonyms, antonyms, and homonyms. However, a person’s mental lexicon often performs even more advanced tasks, such as recognizing what word someone meant to use or anticipating what word will be used before it is spoken. For example, if a person hears someone say, “I need a shovel to eat my ice cream,” they understand that the other person is really looking for a spoon. If someone is walking around while carrying a book and says, “I can’t find my, um…,” another person will know that they are looking for reading glasses.

However, the brain does not simply store words alphabetically as in a printed dictionary.

The speed with which such word identifications are made—less than 200 microseconds—indicates that the brain does not simply store words alphabetically as in a printed dictionary. The fact that people can often recognize a word that will be used before it is spoken also supports this idea.

Instead, the brain appears to have a complicated and intricate cross-filing system that allows words to be identified in a number of ways. This idea has been supported by experiments in which test subjects are given a definition and asked to provide the word that it describes. In some cases, the test subjects are unable to think of the exact word but are able to correctly say what it sounds like or the letter it starts with. This is often described as a word being “on the tip of the tongue” and indicates to researchers that in addition to meaning, the sound of a word and its spelling also play a role in how the word is stored for retrieval.

These and other experiments conducted to determine how people mentally file and find words have also indicated that multiple levels of connections are used in the process. This becomes even more apparent in people who speak more than one language.

Research has shown that the vocabulary of each language is stored separately, but both languages remain connected and can be retrieved in relation to each other. For example, if a person who speaks both English and Spanish is asked in English for the Spanish word for the sandy area near water, the person will quickly recognize that he or she is being asked for the word for “beach” and respond with “playa.”

Research has also indicated that the mental lexicon can be impacted by external factors. Usage appears to be a key factor; words that are used more often are more likely to be easily recalled, while those that are used infrequently may be difficult to recall or forgotten. Aging appears to affect the storage and retrieval process. Other conditions, such as fatigue, illness, and outside distractions like noise or stress, can also affect the ability to retrieve information from the mental lexicon.

Bibliography

Clark, Eve V. “Lexical Acquisition and the Structure of the Mental Lexicon.” Oxford Research Encyclopedia, 29 Mar. 2017, oxfordre.com/linguistics/view/10.1093/acrefore/9780199384655.001.0001/acrefore-9780199384655-e-96. Accessed 21 Jan. 2025.

Emmorey, Karen D., and Victoria A. Fromkin. “The Mental Lexicon.” Linguistics: The Cambridge Survey. Edited by Frederick J. Newmeyer. Cambridge University Press, 1988, pp. 124–149.

He, Huaqung and Yunfei Deng. “The Mental Lexicon and English Vocabulary Teaching.” English Language Teaching, 29 June 2015, files.eric.ed.gov/fulltext/EJ1075455.pdf. Accessed 21 Jan. 2025.

Krethlow, Giulia, et al. "Age‐Specific Effects of Lexical–Semantic Networks on Word Production." Cognitive Science, vol. 44, no. 11, 2020, p. e12915, doi.org/10.1111/cogs.12915. Accessed 21 Jan. 2025.

Lemetyinen, Henna. “Language Acquisition Theory.” Simply Psychology, 7 Sept. 2023, www.simplypsychology.org/language.html. Accessed 21 Jan. 2025.

Nordquist, Richard. “Mental Lexicon (Psycholinguistics).” ThoughtCo, 17 Feb. 2019, www.thoughtco.com/mental-lexicon-psycholinguistics-1691379. Accessed 21 Jan. 2025.