Things become more valuable to us merely by virtue of the fact that we possess them

Owning leads to valuing: Meta-analysis of the mere ownership effect. Michał Białek, Yajing Gao, Donna Yao, Gilad Feldman. European Journal of Social Psychology, November 2 2022. https://doi.org/10.1002/ejsp.2889

Abstract: Mere ownership effect is the phenomenon that people tend to value what they own more than what they do not own. This classic effect is considered robust, yet effect sizes vary across studies, and the effect is often confused for or confounded with other classic phenomena, such as endowment or mere exposure effects. We conducted a pre-registered meta-analysis of 26 samples published before 2019 (N = 3024), which resulted in psychological ownership on valuing effect of g ∼ 0.57 [0.46, 0.69]. Suggestive moderator analyses supported the use of replica as the strongest moderators. Mere ownership effects were different from the null across all moderator categories and in most publication bias adjustments. We consider this as suggestive evidence that psychological owning leads to valuing, yet caution that much more research is needed. All materials, data, and codes are available on https://osf.io/fdyqw/.