Translating the Effects of Environmental Enrichment on Stress and Wound Healing to Human Populations

Abstract

Environmental enrichment has been studied extensively in animals; however, little research has been conducted in humans. This thesis aimed to investigate whether the effects of environmental enrichment on stress and wound healing seen in animal research could translate to humans. Four studies and one scoping review were conducted. Theme one of the thesis studied sensory enrichment (music, soft blankets) and social enrichment (the companion robot Paro), whereas theme two studied visual artworks. In the first theme, two experimental studies examined the effects of music and Paro on skin barrier recovery from a tape-stripping wound. The first study found no significant effects on healing in a healthy, non-stressed sample compared to an active control. The second study found that after exposure to a stressor, interacting with Paro improved healing, compared to an inactive control group. Listening to music did not influence healing, but significantly increased stimulation. The effects of enrichment on healing were mediated by enjoyment. A small randomised pilot study was then conducted to explore effects of Paro on skin outcomes in psoriasis patients. Findings indicated feasibility issues regarding recruitment, yet moderate effect sizes showed some promise. In theme two, a pilot study examined the effects of viewing landscapes, compared to scrambled versions of these artworks, on recovery from a stressor. Viewing landscapes did not reduce stress, but instead increased psychological and physiological stimulation, compared to viewing scrambled artworks. To investigate these effects further, a scoping review was conducted on the effects of viewing artworks on stress. The 14 included studies demonstrated a lack of homologous and rigorous research. However, preliminary results demonstrated reliable decreases in self-reported stress and systolic blood pressure. Moderating factors may explain the divergent effects observed. Overall, the thesis demonstrated that social enrichment (Paro) increased enjoyment and improved skin healing in a healthy stressed population. Other forms of sensory enrichment (music and artwork), increased stimulation, rather than reducing stress, and did not affect healing. These findings suggest that different forms of environmental enrichment may affect health via different pathways in humans. Future research should further investigate the implications of these findings clinically, and explore moderating variables.