Do views of indoor plants have similar health benefits as views of nature or direct experience in natural environments? The benefits of nature exposure to human health are well documented. However, little is known about the psychological benefits of exposure to nature indoors. We studied this topic in a research project at Perkins + Will’s Atlanta office.
The office’s nearly identical floor plans set the stage for a controlled experiment where a floor was filled with 129 plants for two weeks and then participants were tested for psychological well-being and objective memory task performance.
A crossover study was conducted where participants on another floor were also given the same tests without plants. The plants were then moved to the other floor, so that each participant was surveyed with and without the plants.
Data on perceived psychological distress (PERI) and memory task performance (digit span backwards) were collected during each study period from 63 employees. Light levels, cloudy days, self-reported physical and psychological health, and participant demographics were also documented.
Statistical analyses indicated that the plants only marginally improved the psychological health of participants. For the memory task performance, the participants actually performed better without the presence of plants than with the plants.
There are several possible reasons the plants did not have a substantial influence on the psychological health or short term memory of the participants. In an office, there are many factors that effect worker’s psychological well-being and task performance, and plants may go unnoticed in this setting.
One study participant observed that there was initial excitement about the plants among participants, but after a few days, the plants seemed to fade into the background, somewhat like furniture. This comment is consistent with previous studies that find participants may habituate to the presence of the plants; their beneficial effects may be relatively strong in only an initial period after their introduction into the setting.
The abundant natural light and views of nature in the office may have distracted from the influence of the indoor plants. Indoor plants would likely have a greater impact in a windowless basement without views of nature and daylight, like Milton’s desk in Office Space.
Previous studies have shown the greatest impact from plants in settings with less visual stimuli. The participants in our study had higher levels of reported psychological health than typical, so the influence of plants might be lower with these settings.
In other words, the presence of plants might benefit those who work in poorer quality environments and/or those with poorer quality psychological or physical health than participants in this study. A much larger sample size is likely needed to detect smaller anticipated beneficial effects of indoor plants when compared to effects of direct exposure to nature.
The experience of engaging with nature (in the form of an indoor plant) may be different when the participant is working on an activity at a desk as opposed to being engaged with the experience with movement. A potted plant on a desk does not compare to the rich sensory experience of being in nature. It is not surprising the health benefits documented in outdoor environments may not translate to an indoor setting.
While the results did not align with our hypothesis, further study is needed on the influence of plants in an indoor setting.
This guest post is by Micah Lipscomb, ASLA, senior landscape architect at Perkins + Will and Kimberly Rollings, assistant professor, School of Architecture, University of Notre Dame.