Project Summary/Abstract Language is among our most powerful tools for learning and communication. It permits us to learn information that does not, or cannot, manifest perceptually at the time of learning, such as historical facts, hypothetical scenarios, or scientific constructs. This uniquely human power is enabled by abstract verbal reference–an appreciation that words are linked to mental representations that can be established, retrieved and modified, even when their referents are perceptually unavailable. Despite its utmost significance for human learning and communication, questions concerning the developmental origins (Aim 1) and downstream consequences of attaining abstract verbal reference for broader language-mediated learning (Aim 2) remain. To answer these questions, we will conduct one longitudinal and two cross-sectional eyetracking studies, focusing on infants aged 12-22 months. To conduct cross-sectional studies (Experiments 1 and 2), we will develop a novel experimental procedure that will evaluate infants’ ability to establish word-referent links from language input alone and will test infants across a range of ages. The longitudinal study (Experiment 3) will leverage variation in young infants’ ability to resolve abstract verbal reference and identify its consequences for the ability to learn facts from language input later in development. Answering these questions will help us better understand the developmental origins of this fundamental human learning capacity: extracting novel information from language alone, and creating and updating mental representations based on it. The proposed research will have important theoretical implications for our understanding of early linguistic and communicative development. For example, abstract verbal reference may not only extend the reach of infants’ word learning (e.g., to include learning words from overhearing), but may also scaffold their ability to learn abstract concepts and their names. These advantages may be related to infants’ vocabulary growth in the 2nd year of life (Goldfield & Reznick, 1990). Finally, this research raises new theoretical questions. For example, a) What cues do infants rely on to resolve abstract verbal reference, and b) How does infants’ reliance on these cues vary across languages and/or cultural contexts. The proposed research also has strong methodological impact. The procedure in Experiment 1 offers a novel methodological tool for investigating the development of abstract verbal reference in infancy. The semantic priming procedure can be extended to investigate the breadth of infants’ representations of unseen referents. For example, does priming infants with exemplars of superordinate categories lead to a more abstract representation of the target referent than priming with exemplars of the same basic-level category? In addition, due to the use of continuous eyetracking measures over the course of each trial, infants’ performance in this procedu...