Investigating the Contributing Factors of Eye Movements and Stress on Navigation and Spatial Memory

Abstract

Navigation is a complex process that humans rely on daily, from driving to work to finding cereal in the grocery store. Successful navigation usually requires that one accurately remembers spatial information stored in spatial memory. Many factors can contribute to increasing or decreasing navigating success and forming spatial memory; the factors that are the focus of this dissertation were chosen for their pervasiveness in the human experience. The purpose of this dissertation was to investigate the factors of vision, aging, and stress to understand how each may help or hinder navigation. We were particularly interested in how much spatial information is encoded with the eyes and if any additional information can be learned by also moving one’s body, how this relationship changes with age, and how stress affects navigation in larger environments. We also aimed to capture the complex nature of navigation and spatial memory by designing experiments with more naturalistic paradigms to represent behaviors humans do everyday. In Chapter 2, we used mobile eye tracking glasses in a small real-world environment with younger adults to show that vision is sufficient to accurately remember object relationships when the room can be viewed from a single viewpoint. Self-motion cues from walking around the room did not help participants form more accurate spatial memories. Spatial memory of object locations also benefited from longer gaze times at encoding and the presence of nearby landmarks. In Chapter 3, we show how some of these relationships change with age and how some relationships remained the same in a cohort of older adults. For older adults, vision was also sufficient to form spatial memories, although older adults were less accurate in replacing objects than younger adults. However, longer times gazing at objects during encoding and the presence of landmarks near objects did not appear to benefit older adults’ spatial memory, in contrast to results obtained with younger adults. In Chapter 4, we discuss how eye movements during retrieval may play an active role in memory retrieval. Finally in Chapter 5, we investigate how stress affects navigation strategies in a large virtual environment that addresses limitations from past research that limit navigation choices. We taught participants two paths that differed in length and familiarity, administered a stressor, and measured navigation strategies. We successfully induced stress and found that navigation strategies were not altered by our stressors. Participants most often chose to navigate using the shorter learned path but did show a bias toward the more familiar path as well. These results show the importance of vision to form spatial memories and retrieve them, the changes in visual strategies with age, and the resilience of navigation strategies to our stressors.