Relative sensitivity of the mutual exclusivity and novel-name-nameless category assumptions

The mutual exclusivity (ME) assumption states that children affix a novel label to only one unfamiliar object, while the novel-name-nameless category (N3C) assumption states that children affix a novel label to multiple unfamiliar objects. To compare the relative sensitivity of the two assumptions, two types of tasks, with two trials in each, were given to 5-year-olds. In the first trial of each task, all children selected only the unfamiliar object for a novel label, which was consistent with the ME assumption. For the task which did not have the same unfamiliar object in the two trials, 94% of the children selected the object with the same shape but black-white reversed image in the second trial, which was consistent with the N3C assumption. For the task which had the same unfamiliar object in the two trials, 43% of the children selected the same object in the second trial, which was consistent with the ME assumption, and 48% of them selected the object with the same shape but reversed image, which was consistent with the N3C assumption. The findings suggest that the ME and N3C assumptions can be flexibly applied to children's word learning.