Brown Bear, Brown Bear, What Do You See? Speakers Use More Redundant Color Adjectives When Speaking to Children Than Adults.

Cross-culturally, the evolution and production of color words has been linked to communicative efficiency. In visual search tasks for instance, speakers will direct a listener to a target by referring to both its color and shape even when all the targets are unique. Moreover, speakers produce these redundant color adjectives more in languages where they precede the noun, like English, than in ones where they are postnominal, like Spanish. These results are consistent with an Incremental Collaborative Efficiency Hypothesis: the proposal that speakers are sensitive to listeners' online processing demands. If this is the case, speakers should be especially likely to produce redundant color adjectives for children, since children's visual search is especially slow. Here we show that English (Experiment 1) and Spanish-speaking (Experiment 2) adults, and parents and non-parents alike (Experiment 3), selectively generate redundant color adjectives for children. This is not because of a general bias towards being over-informative with children: when redundant color adjectives are uninformative and would not promote efficient search, speakers are no more likely to use them with children than adults (Experiment 4). Finally, children's own use of redundant color adjectives for efficient communication changes over development. Four to ten-year-olds are less likely to produce redundant color adjectives than adults but nonetheless do so selectively when addressing younger children (Experiments 5 and 6). Collectively, these results suggest that sensitivity to listeners' online processing demands is robust, emerges relatively early in development, and may especially benefit young learners.