Infants' preferences for native speakers are associated with an expectation of information.

Humans' preference for others who share our group membership is well documented, and this heightened valuation of in-group members seems to be rooted in early development. Before 12 mo of age, infants already show behavioral preferences for others who evidence cues to same-group membership such as race or native language, yet the function of this selectivity remains unclear. We examine one of these social biases, the preference for native speakers, and propose that this preference may result from infants' motivation to obtain information and the expectation that interactions with native speakers will provide better opportunities for learning. To investigate this hypothesis, we measured EEG theta activity, a neural rhythm shown to index active and selective preparation for encoding information in adults. In study 1, we established that 11-mo-old infants exhibit an increase in theta activation in situations when they can expect to receive information. We then used this neural measure of anticipatory theta activity to explore the expectations of 11-mo-olds when facing social partners who either speak the infants' native language or a foreign tongue (study 2). A larger increase in theta oscillations was observed when infants could expect to receive information from the native speaker, indicating that infants were preparing to learn information from the native speaker to a greater extent than from the foreign speaker. While previous research has demonstrated that infants prefer to interact with knowledgeable others, the current experiments provide evidence that such an information-seeking motive may also underpin infants' demonstrated preference for native speakers.