Children learn words at an incredible rate, acquiring around 6,000 words by age 6 (Carey 2010: 184). If gradual learning is the rule, then words too should be learned gradually across this time. However, this does not appear to be the case. Susan Carey discovered the phenomenon of “fast mapping”, which is one-shot learning of a word (Carey 1978a, 1978b; Carey and Bartlett 1978). Her most influential example investigated children’s acquisition of “chromium” (a color word referring to olive green). Children were shown one of two otherwise identical objects, which only differed in color and asked, “Can you get me the chromium tray, not the red one, the chromium one” (recited in Carey 2010: 2). All of the children handed over the correct tray at that time. When the children were later tested in differing contexts, more than half remembered the referent of “chromium”. These findings have been extended—for example, Markson and Bloom (1997) showed that they are not specific to the remembering of novel words, but also hold for novel facts.