Young two-year-olds' tendency to map novel verbs onto novel actions.

Children tend to select novel objects over familiar ones as the likely referents of novel nouns. This finding is of central importance to several accounts of early word learning. In the current studies, 2-year-olds were shown pairs of videotaped actions, one familiar and one novel, and were asked to select the referents of novel verbs. For actions that did not involve objects, children tended to select the novel action over the familiar one in each of four experiments. For example, they chose the woman who was turning in circles while leaning backwards as "the one who is glarving" more often than the woman who was running. For actions involving objects, novel actions (e.g., shuffling balls) were chosen more often than familiar ones (e.g., kicking balls) in only two of the four experiments. An object-name-blocking mechanism was proposed to account for this last result. The preference for novel actions was also found to be strengthened by preexposing both actions from a test pair, but to be unaffected by preexposing just the novel actions.

What can be learned from something's not being named.

A new word-learning phenomenon is demonstrated and a new word-learning principle is proposed to account for it. In Study 1, 60 3-year-olds were shown a pair of objects and heard a novel label used repeatedly for one, but not for the other. In a forced-choice test of generalization of the label, the latter object was selected less often by the children than one that had not been present during training. This so-called Nominal Passover Effect was the same whether the speaker had completely ignored the comparison object during training or had referred to it with pronouns. The performance of a no-word control group (N = 24) indicated that the effect was not due to a preference for the less exposed of the two choice objects. The effect is consistent with the Exhaustive Reference Principle, which stipulates that whenever a new generic word is used to name something, expect it to be extended to all entities in a situation that the speaker perceives and believes to be exemplars of the name. In Study 2 (N = 48), the Nominal Passover Effect was replicated with 3 new sets of objects and with training language that contained only indefinite forms of reference. The passover experience was often sufficient to counteract children's tendency to generalize a novel label on the basis of perceptual similarity. The passover effect was not evident in free-choice name generalization tests in either study.

How shall a deceptive thing be called?

Thirty-six three-, four- and five-year-olds were asked to select labels for deceptive stimuli (e.g. for an eraser that looked like a pencil). Three types of labelling were investigated--simple (e.g. 'is an eraser'); appearance-predicated (e.g. 'looks like an eraser'); and reality-predicated (e.g. 'is really and truly an eraser'). An age-related appearance--reality shift was observed in simple labelling (e.g. older children were more likely than younger ones to accept eraser and reject pencil as simple names for the pencil-eraser). This trend was robust over method and semantic domain, though weaker with object than with colour labels. As in previous research, older children were more likely than younger ones to map different appearance- than reality-predicated labels onto an item (e.g. to accept that the pencil-eraser looks like a pencil, but is really and truly an eraser); however, all age groups were reluctant to extend more than one name to a stimulus via a common predicate (e.g. to accept two reality-predicated labels for the same object). This one-label-perpredicate pattern was observed more frequently within reality than within appearance predicates; more frequently with colour than with object names, and with questions blocked by predicate than by name. It is argued that younger children maintained this pattern because of inflexible encoding, but that older ones did so because of better understanding of the appearance-reality distinction, greater reality dominance, and a Mutual Exclusivity bias.