Environment and Time: Effect of Anthropogenic and Natural Soundscapes on Temporal Processing

Abstract

As humans, we constantly interact with our immediate environment, and these interactions can shape our cognition and influence various cognitive processes. Environments are broadly categorized as natural or man-made (unnatural). In recent decades, psychologists have extensively studied the impact of these environments on different cognitive activities. This thesis specifically explores how the environment affects temporal processing. Exposure to different types of environments has been shown to distinctly impact our physical and mental health, arousal, affect, stress, mindfulness, and cognitive abilities such as attention. Several studies have investigated the influence of urban and natural settings on temporal processing. However, these studies have not adequately addressed the effect of anthropogenic and natural soundscapes on time perception and the underlying mechanisms, such as the pacemaker or attentional gate, that result in differential temporal processing. Additionally, previous studies often lacked proper control in terms of stimuli and experimental manipulations, posing significant limitations to the findings in this domain. Therefore, this thesis aims to address these limitations and systematically study the influence of natural and anthropogenic soundscapes on temporal processing. We investigated the effect of these soundscapes on a temporal judgment task through three experiments using a temporal bisection task. Sounds were randomly presented in an intermixed design ranging from 400ms to 1600ms in 200ms increments. In Experiment 1, the anthropogenic soundscapes were high-arousing and unpleasant compared to the natural sounds. In Experiment 2, the anthropogenic and natural soundscapes were matched for arousal and valence levels. In Experiment 3, arousal and valence levels were manipulated within the natural sound category. The results of Experiments 1 and 2 consistently showed no significant difference in the mean Difference Limen (DL). However, the Point of Subjective Equality (PSE) for both categories of soundscapes differed significantly, indicating that the anthropogenic soundscape was significantly overestimated relative to the natural soundscape. These results support the attentional gate component, suggesting that participants directed more attention toward the temporal properties of the anthropogenic soundscape, leading to a perceived expansion of time for such sounds. The findings from Experiment 2 suggest that differential temporal processing is not solely caused by variations in arousal or valence levels but also by the category of the soundscapes. In Experiment 3, there was a significant difference in both DL and PSE, indicating that high-arousing natural soundscapes were perceived to be longer compared to low-arousing natural soundscapes. The results of Experiment 3 revealed the role of the pacemaker component. High-arousing natural soundscapes increased the speed of the pacemaker, thereby increasing the number of pulses generated, resulting in the overestimation of the duration of high-arousing natural soundscapes.