Older infants are good referential learners. That is, at around 14-months of age, they begin to learn the verbal labels of objects and events around them. However, referential learning can be made more challenging by increasing the lexical similarity between labels. The primary goal of this study was to examine whether an adult speaker's ostensive cues and eye gaze-object contingency could augment referential learning in 14-month-old infants under difficult conditions (i.e., minimal pair labels). In Experiment 1, infants were familiarized and tested on two word-object associations with minimal pairs (e.g., "bin" and "din"), presented on an eye-tracker. Importantly, each session began when infants made eye contact with a female speaker on the screen, and she continually looked at and verbally referenced each object in an infant-directed style. On test trials when the familiar object+label was switched, infants significantly increased their visual scanning of the speaker's mouth compared to control trials. In Experiment 2, the same procedure was followed with a new group of 14-month-olds, except that the speaker now looked in the opposite direction from the objects on the screen, but continued to label them with minimal pairs in an infant-directed style. In contrast to the results of Experiment 1, infants in this latter experiment did not differentially attend to any area of her face during the switch trials. This pattern of results shows that the ostensive nature of a social partner augments infants' referential learning under cognitive challenge, but it is the contingent nature of the speaker's regard to what is being labeled that is a necessary factor in promoting learning. / Ph. D.

The primary goal of this study was to examine how infants' language and emotion development intersect around the end of the first year. Specifically, is learning enhanced when a speaker is happy vs. neutral? Eighteen 12-month-old infants were familiarized and tested on four word-object associations that varied in bimodal emotion (happy vs. neutral), which were presented on a Tobii© T60 eye-tracker. Familiarization trials comprised of actresses looking towards and labeling a target object while ignoring a non-target distractor object on the opposite side of the screen. It was expected that infants would demonstrate better learning of word-object associations during the test trials when the speaker was happy. This hypothesis was partially supported, in that infants demonstrated a novelty preference for the novel non-target object compared to the familiar target object in the happy test trials only. However, no difference in attention was seen in happy test trials with the familiar target object and a familiar non-target object or for either of the neutral test trials. A second goal of this study was to examine infant-parent correspondence in emotion processing. Both infants and parents were presented with a series of emotion pairs on the eye-tracker, and the correlations between their gaze patterns were examined. In general, infants and parents had little to no correspondence in first look tendencies or overall fixation duration to either face in the pair. They also fixated on different areas of the face (infants on mouth region, parents on eye region). Finally, parental sensitivity was examined using a free-play interaction task. Parents' sensitivity was analyzed with respect to measures of infants learning during the language task as well as other infant characteristics (e.g. temperament, vocabulary). Overall, these findings add to the relatively limited research examining the intersection of language and socioemotional development in infancy. / Ph. D.