This thesis investigated the effects of three sources of motorized noise on laboratory
participants’ evaluations of landscape scenes, self-reported affective states, and physiological
responses in simulated national park settings. Seventy-seven laboratory participants completed
landscape assessments along 8 aesthetic dimensions and reported affective states while listening
to audio clips of natural sounds, propeller planes, motorcycles, and snowmobiles. Each
participant experienced all scenes and sound conditions in a pseudo-randomized order. The
change from the natural sound baseline for each motorized source of noise was calculated.
Results indicated that all motorized sources of noise had detrimental impacts on landscape
assessments and self-reported affective states, compared to natural sounds. Motorcycle noise
was demonstrated to have the largest negative impact on landscape assessments. Physiological
response was also affected by experimental noise in some of the conditions (with the strongest
effect in the snowmobile condition), but a consistent pattern of results failed to emerge to suggest
that negative impacts to human physiology could be reliably detected under the present
methodology. In addition to confirming that noise from motorized recreation has significant
social impacts on potential park visitors, this simulation suggests that the specific source of the
noise is an important factor in observer evaluations. These results could help park managers
prioritize their educational and regulatory strategies for minimizing adverse impacts by
motorized vehicles on natural soundscapes. Important advances in soundscape research
methodology are also presented.