In cognitive psychology, fast mapping is the term used for the hypothesized mental process whereby a new concept is learned (or a new hypothesis formed) based only on minimal exposure to a given unit of information (e.g., one exposure to a word in an informative context where its referent is present). 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 to successfully use the fast mapping process, a child must possess the ability to use "referent selection" and "referent retention" of a novel word. There is evidence that this can be done by children as young as two years old, even with the constraints of minimal time and several distractors. Previous research in fast mapping has also 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. While children have also displayed the ability to have equal recall for other types of information, such as novel facts, their ability to extend the information seems to be unique to novel words. This suggests that fast mapping is a specified mechanism for word learning. The process was first formally articulated and the term 'fast mapping' coined Susan Carey and Elsa Bartlett in 1978. Evidence against Today, there is 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