While children aged 1;10 and 2;1 show only a modest rate of mapping novel nouns onto unfamiliar rather than familiar objects, children aged 1;4 and 1;8 show a high rate. Two studies with young 2-year olds found the noun-mapping preference prevalent, but unless initial choices are strongly reinforced, increase in salience of familiar kinds lures some into error. A third study provided support. (Author/MSE)