Cognitive and Neural Correlates of Processing Spatial Relations in Humans

Abstract

Human cognition has long been thought to exceed that of other animals; however, what it is that makes humans “so smart” continues to be questioned. Gentner argues that language and relational reasoning together elevate human cognition and she takes a developmental approach to support her theory. This project takes a similar approach to Gentner’s. I examined the relationship between language and relational reasoning in children, specifically as they are learning the relational terms for right and left as compared to relations for terms that they already know (i.e., above/below). What sets this project apart from Gentner’s work is that I also looked at the effect of lateralization on children’s performances as well the neural mechanisms underlying these same relational judgments in adults. Some of the neural mechanisms underlying relational reasoning in humans and monkeys are known. However, it is not known whether one set of relations (i.e., above/below) should be advantaged over the other (i.e., right/left) in both verbal and nonverbal modalities. To answer this question, I have developed a set of tasks to examine the following queries: 1) how verbal and nonverbal knowledge of above/below/right/left develops from 5 years to 10 years of age, 2) whether verbal knowledge aids performance on a nonverbal task that requires judgments of these relations, 3) whether strength of handedness promotes either verbal or nonverbal performance, and 4) what the neural correlates of these judgments are. The chapters of this thesis are organized to address each question separately. In the first chapter, I give a general overview of the work already done regarding these questions. In Chapter 2, I describe the spatial relational task used to investigate each question. Chapters 3-6 report on the findings from each of my four questions and Chapter 7 provides a general discussion of what this research adds to the current literature. Overall, my findings suggest that language is not necessary for relational coding to emerge, verbal and nonverbal knowledge of relations follow different developmental trajectories, lateralization (handedness) does not aid in learning relations, and the two sets of spatial relations are represented differently in the brain.