Vocabulary learning by children can be characterized by many biases. When encountering a
new word, children as well as adults, are biased towards assuming that it means something totally
different from the words that they already know. To the best of our knowledge, the 1st mathematical
proof of the optimality of this bias is presented here. First, it is shown that this bias is a particular case of the maximization of mutual information between words and meanings. Second, the optimality is proven within a more general information theoretic framework where mutual information maximization competes with other information theoretic principles. The bias is a prediction from modern information theory. The relationship between information theoretic principles and the principles of contrast and mutual exclusivity is also shown.Peer ReviewedPostprint (published version
