Geometric and functional knowledge in the acquisition of spatial language

Considerable debate surrounds the nature of spatial categories, beginning with the observation that all languages use a limited and closed set of terms to encode object location and what appears to be a large and diverse set of object relations and configurations (Talmy, 1985). In previous work, Johannes, Landau and colleagues (Johannes, Wilson, & Landau, 2012, submitted; Landau, Johannes, Skordos, & Papafragou, under review) proposed that the structure of the conceptual categories of Containment and Support that underlie spatial language is reflected in the probabilistic use of spatial terms like in and on. The work in this thesis expands on these earlier findings by exploring the nature of the conceptual information underlying probabilistic spatial expression use and the relationship between conceptual knowledge and spatial expression use across development. The studies probe relationships between adults' and children's spatial expression use and a small set of geometric features, derived from studies of pre-linguistic spatial cognition knowledge (Hespos & Baillargeon, 2001, 2008; Hespos & Spelke, 2004, 2007), and a functional feature, Locational Control, adapted from psycholinguistic studies of in and on (Garrod, Ferrier, & Campbell, 1999). The results of three studies show that adults' and children's use of different types of spatial expressions (including BE + in(side)/on (top) and lexical verbs) for a large and diverse set of Containment and Support items are predicted by different combinations of geometric and functional features. Geometric features show consistent relationships to expression use across development, while Locational Control differs in its relationship to adults' and children's use of different expression types. Parents of 4- and 6-year-old participants also provided estimates of how likely they were to use different expression types to describe the same set of experimental items to their children. Including these estimates, alongside features, in models of child expression use improved the accuracy of model predictions, particularly for children’s use of lexical verb expressions, which initially showed weak relationships to feature ratings. These findings are among the first to account for spatial language usage and development as a complex function of spatial (geometric and functional) knowledge and input environment and the first to systematically examine spatial encoding for such a diverse sample of items that are representative of the everyday object configurations that children and adults encounter in the world