Isolating the factors underlying cognitive demands of visual environments

  • Daria A Burtan

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


Exposure to urban environments over a relatively long period of time has been found to be more cognitively demanding than exposure to nature environments, even if sensory input is received only through visual cues. Yet, it remains unclear which parameters contribute to such environmentally-induced cognitive load. The aim of this thesis was to understand the causal mechanisms underlying this effect, using gait kinematics and reaction times as an objective measure of cognitive load changes in real-time. Over six studies, I teased apart factors that might contribute to cognitive load. In particular, I investigated the impact of low-level visual features (such as image statistics: contrast distribution, fractal dimensions, and the amount of “greenery” in a visual scene), visual discomfort and aesthetics on gait kinematics. Neither greenery nor contrast distribution were predictive of gait kinematics; however, walking towards images with fractal properties outside the range typically found in nature scenes slowed gait, indicating higher demands on cognitive load. This suggests that some but not all low-level image statistics play a role in environmentally-induced cognitive load. Moreover, an interaction between fractal dimensions and visual discomfort rather than aesthetics seemed to contribute to environmentally-induced cognitive load, with a strong negative relationship between visual discomfort and liking. Data presented in this thesis have gone some way towards enhancing our understanding of how different visual features of an environment impact cognitive abilities and suggest that visual stress/discomfort could be at the core of cognitive load differences between nature and urban environments. More broadly, these results may inform future design of healthy and inclusive cities, which is one of the major global health challenges.
Date of Award27 Sept 2022
Original languageEnglish
Awarding Institution
  • University of Bristol
SupervisorUte B Leonards (Supervisor) & J Burn (Supervisor)


  • Environment
  • Cognitive Load
  • Image Statistics
  • Aesthetcs
  • Visual Discomfort
  • Gait

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