The Blind Spot in Research on Nature’s Benefits: Restorative versus Instorative Effects and Potential Biases.

Environmental psychology has extensively documented the restorative effects of nature: the recovery of cognitive resources and emotional well-being following stress or fatigue. Yet, the field may have overlooked instorative effects, where nature enhances functioning from a neutral baseline without prior depletion. We reviewed 54 studies (61 experiments, 19962024) investigating nature versus urban exposure effects on cognition, affect, and perceived restoration. Studies were categorized as explicit stressor (deliberate pre-exposure stress induction), implicit stressor (pre-exposure assessments likely inducing fatigue), or instorative (no prior stressor/assessment). Using an iterative, data-driven approach inspired by Grounded Theory, we analyzed study characteristics, exposure types, and the proportion reporting beneficial effects. Restorative studies vastly outnumbered instorative studies (45 vs. 8), revealing substantial research bias. Despite limited representation, instorative studies demonstrated high success rates: all cognition studies reported positive effects, while two-thirds examining affect showed benefits. Explicit stressor studies showed stronger effects than implicit stressor studies, suggesting dose-response relationships. Differentiating between instorative and restorative effects remains difficult, as no validated tools specifically assess instoration. The widely used Perceived Restorativeness Scale primarily measures general environmental benefits, conflating restoration and instoration. Studies predominantly employed young, Western samples and brief laboratory exposures, limiting ecological validity. The capacity of nature to enhance, rather than merely restore, functioning is underexplored. Future research should investigate instorative effects using ecologically valid paradigms with neutral baselines, refined theoretical models, standardized terminology, and appropriate questionnaires that distinguish between instorative and restorative effects.