Making Time for Nature: Visual Exposure to Natural Environments Lengthens Subjective Time Perception and Reduces Impulsivity

Abstract

Impulsivity in delay discounting is associated with maladaptive behaviors such as overeating and drug and alcohol abuse. Researchers have recently noted that delay discounting, even when measured by a brief laboratory task, may be the best predictor of human health related behaviors (e.g., exercise) currently available. Identifying techniques to decrease impulsivity in delay discounting, therefore, could help improve decision-making on a global scale. Visual exposure to natural environments is one recent approach shown to decrease impulsive decision-making in a delay discounting task, although the mechanism driving this result is currently unknown. The present experiment was thus designed to evaluate not only whether visual exposure to natural (mountains, lakes) relative to built (buildings, cities) environments resulted in less impulsivity, but also whether this exposure influenced time perception. Participants were randomly assigned to either a natural environment condition or a built environment condition. Participants viewed photographs of either natural scenes or built scenes before and during a delay discounting task in which they made choices about receiving immediate or delayed hypothetical monetary outcomes. Participants also completed an interval bisection task in which natural or built stimuli were judged as relatively longer or shorter presentation durations. Following the delay discounting and interval bisection tasks, additional measures of time perception were administered, including how many minutes participants thought had passed during the session and a scale measurement of whether time "flew" or "dragged" during the session. Participants exposed to natural as opposed to built scenes were less impulsive and also reported longer subjective session times, although no differences across groups were revealed with the interval bisection task. These results are the first to suggest that decreased impulsivity from exposure to natural as opposed to built environments may be related to lengthened time perception.

Fig 1. Indifference points as a function of delay for the natural and built conditions.

Median indifference points as a function of delay (months) for natural (circles) and built (triangles) conditions. Lines show the best fit of Eq 1 to the median indifference points.

Fig 2. Area Under the Curve for the natural and built conditions.

Mean AUC for the natural (open bar) and built (filled bar) conditions. Vertical lines represent the standard error of the mean.

Fig 3. Estimation of session length in minutes for the natural and built conditions (left panel) and scatter plot of AUC as a function of Numerical Estimate (right panel).

Mean estimate of session length in minutes for the natural (filled bar) and built (open bar) conditions (left panel). Horizontal lines represents the actual session length mean rounded to the nearest minute for both the natural and built conditions. Scatter plot of AUC as a function of Numerical Estimate in Minutes (right panel)—circles and triangles represent participant responses in the natural and built conditions, respectively. Asterisk represent significant differences in time estimation across natural and built conditions. Vertical lines represent the standard error of the mean.

Fig 4. Score on the scale long task for the natural and built conditions (left panel) and scatter plot of AUC as a function of Scale Long Score (right panel).

Mean score on the 'scale long task' for the natural (filled bar) and built (open bar) conditions (left panel). Vertical lines represent the standard error of the mean. Scatter plot of AUC as a function of the Scale Long Score (right panel)—circles and triangles represent participant responses in the natural and built conditions, respectively.