The Relationship Between Spatial Language and Spatial Cognition in the Development of the 'Middle' Relation

Children's ability to use multiple landmarks relationally (e.g., find an object between two landmarks) and related spatial terms (e.g., "middle," "by") both develop during the preschool years. Research has extensively outlined the development of these abilities, however, the relationship between these skills is unknown. These experiments aimed to extend previous research by examining how the development of the spatial relational term "middle" and children's ability to use the middle relation to search among multiple landmarks mutually influence one another. The goal of Experiment 1 was to establish when children acquire the word "middle" and whether the acquisition of the spatial term is related to use of the middle relation in a search task. Seventy-two children ages two- to four-years-old participated in a landmark extension task in which children were trained to search in the middle of a small array of multiple landmarks and were tested on the ability to extend the middle relation to an expanded landmark array. During training, children heard one of two language cues: 1) middle (i.e., "I am hiding the toy in the middle.") or 2) control (i.e., "I am hiding the toy here ."). Afterward, participants completed a forced-choice "middle" comprehension test. Findings showed a strong relationship between spatial language and spatial cognition, such that children who showed comprehension of the term "middle" and children who heard a middle language cue were more likely to extend the middle relation to the expanded landmark array. Experiment 2 used an eye-tracking procedure to test whether children under age two evidence comprehension of the term "middle" and whether differences in comprehension are associated with differences in gaze patterns to multiple-landmark arrays. Twenty-eight children ages 18- to 24-months-old were shown sets of multiple objects and asked to look at objects in a particular spatial position. Differences in children's fixation duration to the middle object on middle cued trials were positively related to age, vocabulary size, and parent reports of children's "middle" comprehension. Children's comprehension was additionally related to search behavior in the landmark task, such that children who were reported by parents to understand the term "middle" showed longer fixations to the middle region of the expanded landmark array. Thus, development in comprehension of the word "middle" occurs at much younger ages than previously tested in investigations of the middle relation, and this development is related to fundamental changes in children's landmark use. The goal of Experiment 3 was to elucidate the role of language cues in the landmark task. Fifty-four children ages two- to three-years-old were tested using the same procedure as in Experiment 1, with the addition of a novel language condition (i.e., "I am hiding the toy in the blicket."). Children who heard middle or novel language cues evidenced more middle searches in the expanded landmark array, suggesting that rather than drawing on experience with the specific spatial term "middle," language cues serve a more general function to highlight the relationship between multiple landmarks and the goal. As a whole, these three experiments demonstrate the course of development for the middle spatial relation and reveal the central role of spatial language in children's developing ability to reason about spatial relations.