This land is my land: Psychological ownership increases willingness to protect the natural world more than legal ownership

Abstract Pro-environmental appeals that strive to protect a natural area often invoke psychological ownership, or a personal, emotional connection to the place. However, in Western cultures, legal ownership is often suggested as a way to preserve natural resources and avoid the “commons problem.” Based on research on human prosocial behavior, we hypothesized that psychological ownership would be a more effective way to preserve natural resources. Using an online U.S. sample (N = 543), we manipulated people's sense of ownership for natural areas, with a fully-factorial design. We confirmed that activating the motives of ownership produced a sense of psychological ownership of the place and “mine-ness,” associated with similar psychological ownership attributes as occurs in other domains (i.e., intimate familiarity, incorporation into the self-identity, investment of time/effort, positive memories and experiences). Legal owners also experienced a sense of mine-ness and felt more control and territoriality over the place, but felt less of a psychological connection and rated the psychological attributes lower. As predicted, psychological ownership increased people's willingness to protect and oppose exploiting natural areas—particularly for self-reported willingness and hours donated to preserve the place. This may explain why legal ownership often fails to reduce environmental exploitation in Western populations, despite fostering a sense of responsibility toward owned resources. Invoking psychological ownership may be a more effective way to encourage environmental protection.