The Processes of Path Integration and Landmark-based Navigation in Human Adults
Creators: Qi, Yafei
Publisher: name: University of Alberta Library
Year: 2024

<p>An effective navigation process requires the ability to determine the navigators’ current position and heading in the environment (referred to as self-localization) and localize the points of interest, such as home. Humans and non-human animals typically use self-motion cues (i.e., path integration) and landmarks (i.e., piloting) to keep track of their position and orientations and find their homes. Chapter 1 reviews the previous research regarding the usage of these two processes in human navigation and their contribution to determining orientation and briefly discusses the systematic homing errors observed in path integration. Chapter 2 presents a study that examined the usage of different landmarks in human orientation and Chapter 3 presents a study that examined the sources of systematic biases in human path integration. Chapter 4 summarizes the findings of the two studies and discusses the implications and limitations of these studies.<br>
Chapter 2 involves a study investigating the roles of distal and proximal landmarks in determining human orientations. It has been a long-standing theoretical argument and foundational assumption in research paradigms that distal landmarks dominate as orientation cues over proximal landmarks. Participants learned object locations with proximal and distal landmarks in an immersive virtual environment. After walking a path without seeing objects or landmarks, participants were disoriented and pointed to the objects with the reappearance of a proximal landmark being rotated -50°, a distal landmark being rotated 50°, or both (Conflict). Heading errors were examined. Experiment 1 manipulated the relative cue precision. Results indicate that besides the relative cue precision, prior knowledge of distal cue dominance also influences orientation cue usage. In Experiments 2 and 3, participants walked a path stopping at one object location. Participants were informed of it explicitly in Experiment 2 but not in Experiment 3. Results showed that distal cue dominance still occurred in Experiment 3. However, in Experiment 2, proximal cue dominance appeared, and it was not predicted by the relative cue precision. These results suggest that prior knowledge of proximal cue dominance might have been invoked by the instruction of locations. Consistent with the Bayesian inference model, human cue usage in orientation is determined by relative cue precision and prior knowledge. The choice of prior knowledge can be influenced by instructions.<br>
Chapter 3 involves a study employing computational modeling to investigate potential sources of systematic biases observed in human path integration. Systematic biases (compression patterns in the inbound responses) have been well documented in human triangle completion tasks. Cross-validation modeling was used to compare three plausible theoretical models that assume that systematic errors occur in the encoding outbound path solely (encoding-error model), executing the inbound responses solely (execution-error model), and both (bi-component model), respectively. Unlike traditional triangle completion tasks with a single inbound response (i.e., the homing vector) for each outbound path, the triangle-completion task used in this study required participants to indicate three learned locations (including the home location) during the response phase. The results demonstrated that the bi-component model outperformed the other models in accounting for the systematic errors using multiple inbound responses. This finding suggests that both encoding the outbound path and executing the inbound responses contribute to the systematic biases in human path integration. Additionally, the results showed that the algorithm using only the home response could not distinguish among these three models, suggesting that the typical triangle-completion task with only the home response for each outbound path cannot determine the sources of the systematic biases.</p>