Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology and Physical Education

Faculty/School

Faculty of Science

First Advisor

Dr. Michael E. Cinelli

Advisor Role

Professor

Second Advisor

Dr Bradford J. McFadyen

Advisor Role

Professor

Abstract

Collision avoidance during locomotion is an important skill that people must master to successfully navigate through dynamically changing environments. Environments are cluttered with objects that are either goals (attraction points) or obstacles (repulsion points), such that locomotion must be guided towards goals and away from obstacles. While navigating towards a goal, individuals maintain an elliptically shaped ‘personal space’ between their own body and that of the obstacle(s). The size of personal space (degree of repulsion) is modulated depending on the specific situation. Collision avoidance research has typically utilized inanimate objects such as poles, however recent findings suggest that the amount of personal space required with inanimate objects is distinct from that used to avoid another person. Historically, person-to-person collision avoidance research has examined avoidance behaviours during different situation-specific scenarios, such as mutual or joint-task avoidance, passing through apertures, and interacting on various angles. Person-person research has not, however, fully taken person-specific characteristics into consideration as factors that may contribute to different avoidance behaviours. It is unknown whether humans perceive all humans the same way or if certain external-characteristics (i.e., one’s perception of others) dictate how collisions are strategically avoided with another human. Furthermore, it is unknown if behaviours are robust across all individuals or if there are certain internal-characteristics (i.e., one’s perception of self) that influence collision avoidance behaviours. The overarching goal of my PhD was to identify the person-specific characteristics that mediate changes in avoidance behaviours, in a young adult population.

To address this, five collision avoidance studies were conducted in the real world or virtual reality. The first study (conducted at Wilfrid Laurier University) examined collision avoidance behaviours when circumventing two physically different sized individuals. Results from Study 1 revealed that individuals circumvent people with a larger body size with more space at the time of crossing from the center of mass compared to a person with a smaller body size. The second study (conducted at Wilfrid Laurier University) was a follow-up focused on avoidance behaviours when circumventing an individual whose body size was artificially increased using shoulder pads. Study 2 demonstrated that when an artificial extension (shoulder pads) is added to a stationary person, avoidance behaviours are unchanged. Instead, results determined a side-bias where clearance was smaller for left-side avoidance. The third study (conducted at University Rennes II, FR), focused on determining the influence of a virtual human’s age-related (older vs younger) appearance and gait characteristics on collision avoidance strategies. Study 3 found that young adults circumvent with a larger clearance when interacting with a virtual pedestrian who possesses older adult-like characteristics. Study 4 (conducted at Université Laval) determined differences in the avoidance and gaze behaviours of athletes and non-athletes during an avoidance task with a virtual pedestrian who unpredictably steered to a new direction. Avoidance and gaze behaviours were different between athletes and non-athletes during early planning, but similar during late planning. Unpredictable steering behaviours of an approaching pedestrian led to a larger clearance at the time of crossing. Study 5 (conducted at Wilfrid Laurier University) was aimed at determining if an acute nociceptive stimulus (via topical capsaicin cream) alters avoidance behaviours. Cutaneous discomfort on the lateral aspect of the arm did not alter young adults’ avoidance behaviours. However, a learning effect was observed as avoidance was different during the first trial.

Together, these studies suggest that additional perceptual factors are considered when avoiding collisions with other people. The results of this dissertation demonstrate that during obstacle avoidance tasks, one’s personal space is influenced by, 1) the external-characteristics of an opposing pedestrian, and 2) the internal-characteristics of oneself. Understanding the typical behaviours for circumventing pedestrians and knowing how specific external- and internal-factors influence personal space provides the necessary groundwork for understanding how these behaviours are altered with age or disease. Furthermore, this work provides valuable information about human inter-personal distances (i.e., proxemics), which may be applicable to re-designing the simulation models of interactions between pedestrians used by engineers to expand crowd simulations, to develop architectural plans for urban centers, design robots to safely navigate unfamiliar environments, or properly plan exit routes in buildings.

Convocation Year

2024

Convocation Season

Spring

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Available for download on Monday, November 23, 2026

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