Longer looks for language: Novel labels lengthen fixation duration for 2-year-old children

The language infants hear guides their visual attention; infants look more to objects when they are labeled. However, it is unclear whether labels also change the way infants attend to and encode those objects-that is, whether hearing an object label changes infants' online visual processing of that object. Here, we examined this question in the context of novel word learning, asking whether nuanced measures of visual attention, specifically fixation durations, change when 2-year-olds hear a label for a novel object (e.g., "Look at the dax") compared with when they hear a non-labeling phrase (e.g., "Look at that"). Results confirmed that children visually process objects differently when they are labeled, using longer fixations to examine labeled objects versus unlabeled objects. Children also showed robust retention of these labels on a subsequent test trial, suggesting that these longer fixations accompanied successful word learning. Moreover, when children were presented with the same objects again in a silent re-exposure phase, children's fixations were again longer when looking at the previously labeled objects. Finally, fixation duration at first exposure and silent re-exposure were correlated, indicating a persistent effect of language on visual processing. These effects of hearing labels on visual attention point to the critical interactions involved in cross-modal learning and emphasize the benefits of looking beyond aggregate measures of attention to identify cognitive learning mechanisms during infancy.