In cognitive psychology, fast mapping is a hypothesized mental process whereby a new concept can be learned (or a new hypothesis formed) based only on a single exposure to a given unit of information. Fast mapping is thought by some researchers to be particularly important during language acquisition in young children, and may serve (at least in part) to explain the prodigious rate at which children gain vocabulary. In order for children to be able to acquire the fast mapping process, they must possess "referent selection" and "referent retention" of that word, but fast mapping does not explain the thinking process of what an object intrinsically means. Previous research in fast mapping has shown that children are able to retain a newly learned word for a substantial amount of time after they are subjected to the word for the first time (Carey and Bartlett, 1978). Further research by Markson and Bloom (1997), showed that children can remember a novel word a week after it was presented to them even with only one exposure to the novel word. The process was first formally articulated and the term 'fast mapping' coined by Harvard researchers Susan Carey and Elsa Bartlett in 1978.
- 1 Evidence against Fast Mapping
- 2 Cross Situational Learning versus Propose but Verify
- 3 Variables Affecting a Child's Ability to use Fast Mapping
- 4 Evidence of Fast Mapping in Animals
- 5 Fast Mapping in the Deaf Population
- 6 Fast Mapping in Individuals with ADHD
- 7 References
- 8 External links
Evidence against Fast Mapping
Today, there is ample evidence to suggest that children do not learn words through ‘fast mapping’ but rather learn probabilistic, predictive relationships between objects and sounds that develop over time. Evidence for this comes, for example, from children’s struggles to understand color words: although infants can distinguish between basic color categories, many sighted children use color words in the same way that blind children do up until the fourth year. Typically, words such as “blue” and “yellow” appear in their vocabularies and they produce them in appropriate places in speech, but their application of individual color terms is haphazard and interchangeable. If shown a blue cup and asked its color, typical three-year olds seem as likely to answer “red” as “blue.” These difficulties persist up until around age four, even after hundreds of explicit training trials. The inability for children to understand color stems from the cognitive process of whole object constraint. Whole object constraint is the idea that a child will understand that a novel word represents the entirety of that object. Then, if the child is presented with further novel words, they attach inferred meanings to the object. However, color is the last attribute to be considered because it explains the least about the object itself. Children’s behavior clearly indicates that they have knowledge of these words, but this knowledge is far from complete; rather it appears to be predictive, as opposed to all-or-none.
An alternate theory of deriving the meaning of a newly learned words by young children during language acquisition stems from John Locke's "associative proposal theory". Compared to the "intentional proposal theory", associative proposal theory refers to the deduction of meaning by comparing the novel object to environmental stimuli. A study conducted by Yu & Ballard (2007), introduced cross-situational learning, a method based on Locke's theory. Cross-situtational learning theory is a mechanism in which the child learns meaning of words over multiple exposures in varying contexts in attempt eliminate uncertainty of the word's true meaning on an exposure-by-exposure basis.
On the other hand, more recent studies  suggest that some amount of fast mapping does take place, questioning the validity of previous laboratory studies that aim to show that probabilistic learning does occur. A critique to the theory of fast mapping is how can children connect the meaning of the novel word with the novel word after just one exposure? For example when showing a child a blue ball and saying the word "blue" how does the child know that the word blue explains the color of the ball, not the size, or shape? If children learn words by fast mapping than they must use inductive reasoning to understand the meaning associated with the novel word. A popular theory to explain this inductive reasoning is that children apply constraints to the situation where a novel word is introduced. There are speculations as to why this is; Markman and Wachtel (1988) conducted a study that helps explain a possible cause of fast mapping. They claim children adhere to the theory of mutual exclusivity (the assumption that the children expect an object to only have one name). In their experiment, children were presented with an object that they either were familiar with or was presented with a whole object term. Markman and Watchel concluded that the mere juxtaposition between familiar and novel terms may assist in part term acquisition. In other words, children will put constraints on themselves and assume the novel term also refers to the object, but only a part of it. There have been six lexical constraints proposed (reference, extendibility, object scope, categorical scope, novel name, conventionality) that guide a child's learning of a novel word. When learning a new word children apply these constraints. However, this purposed method of constraints is not flawless. If children use these constraints there are many words that children will never learn such as actions, attributes, and parts.
Cross Situational Learning versus Propose but Verify
Another modification in the fast mapping theory is if fast mapping occurs to learn a novel word how exactly is the meaning of the novel word learned? An experiment performed in October 2012 by the Department of Psychology by University of Pennsylvania, researchers attempted to determine if fast mapping occurs via cross situational learning or propose but verify. In cross situational learning, listeners hear a novel word and store multiple conjecture of what the word could mean based on its situational context. Then after multiple exposures the listener is able to target the meaning of the word by ruling out conjectures. In propose but verify, the learner makes a single conjecture about the meaning of the word after hearing the word used in context. The learner then carries that conjecture forward to be reevaluated and modified for consistency when the word is used again. The results of the experiment seems to support that propose but verify is the way by which learners fast map new words. http://www.psych.upenn.edu/~gleitman/papers/2013_Trueswell_Medina_Hafri_Gleitman_CognitivePsychology.pdf
Criticisms of Fast Mapping
There is also controversy over whether words learned by fast mapping are retained or forgotten. Previous research has found that generally, children retain a newly learned word for a period of time after learning. One study, performed by Markson and Bloom (1997), showed that children remembered words up to 1 month after the study was conducted. However, more recent studies have shown that words learned by fast mapping tend to be forgotten over time. In a study conducted by Vlach and Sandhofer (2012), memory supports, which had been included in previous studies, were removed. This removal appeared to result in a low retention of words over time. This is a possible explanation for why previous studies showed high retention of words learned by fast mapping.
Some researchers are concerned that experiments testing for fast mapping are produced in artificial settings. They feel that fast mapping doesn't occur as often in more real life, natural situations. They believe that testing for fast mapping should focus more on the actual understanding of a word instead of just its reproduction. For some, testing to see if the child can use the new word in a different situation constitutes true knowledge of a word, rather than simply identifying the new word.
Variables Affecting a Child's Ability to use Fast Mapping
Fast Mapping and Socio-Economic Status
If a child is exposed to a low-SES household environment, they may be deprived of the constant attention more often given by high-SES households. Less attention means the child will be exposed to less words and therefore language development, including fast mapping, may suffer.
Fast Mapping and Face to Face Interaction
It has been proven that the amount of face to face interaction a child has with their parent affects his or her ability to fast map novel words. Interaction with a parent leads to more exposure of different words in different contexts, which in turn promotes language acquisition. Face to face interaction cannot be replaced by TV exposure or educational shows. Although educational shows attempt to promote language acquisition through methods such as repetition, there is an essential piece missing. Children are not able to receive the same amount of trial and error teaching when there is no one to monitor or correct them while watching an educational show.
Evidence of Fast Mapping in Animals
It appears that fast mapping is not only limited to humans, but can occur in dogs as well. In an experiment, a dog, named Rico, was able to learn the labels of over 200 various items. He was also able to identify novel objects simply by exclusion learning. Exclusion learning is simply learning the name of a novel object because you are familiar with the names of the other objects in the group already. The researchers, who conducted the experiment, mention the possibility that a language acquisition device specific to humans does not control fast mapping. They believe that fast mapping is possibly directed by simple memory mechanisms.
Fast Mapping in the Deaf Population
A study by Lederberg et al, was performed to determine if deaf and hard of hearing children fast map to learn novel words. In the study when the novel word was introduced the word was both spoken and signed. Then the children were asked to identify the referent object and even extend the novel word to identify a similar object. The results of the study indicated that deaf and hard of hearing children do perform fast mapping to learn novel words. However, compared to children with normal hearing (aging toddlers to 5 years old) the deaf and hard of hearing children did not fast map as accurately and successfully. The results showed a slight delay which disappeared as the children were a maximum of 5 years old. The conclusion that was drawn from the study is that the ability to fast map has a relationship to the size of the lexicon. The children with normal hearing had a larger lexicon and therefore were able to more accurately fast map compared to deaf and hard of hearing children who did not have as large of a lexicon. It is by around age 5 that deaf and hard of hearing children have a similar size lexicon to 5 year old children of normal hearing. This evidence supports the idea that fast mapping requires inductive reasoning so the larger the lexicon (number of known words) the easier it is for the child to reason out the accurate meaning for the novel word. M. Diane Clark, Marc Marschark, Michael A. Karchmer. (2001). Context, Cognition, and Deafness. 103-107.
Fast Mapping in Individuals with ADHD
An experiment was performed to assess fast mapping in adults with typical language abilities, disorders of spoken/written language (hDSWL), and adults with hDSWL and ADHD. The conclusion draw from the experiment revealed that adults with ADHD were the least accurate at "mapping semantic features and slower to respond to lexical labels." The article reasoned that the tasks of fast mapping requires high attentional demand and so "a lapse in attention could lead to diminished encoding of the new information." 
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