“…Nonzero payments have been attributed to knowledge of prices paid by other consumers (Soule and Madrigal 2015), having a shared social responsibility with the seller (Gneezy et al 2010), possessing high levels of fairness and altruism (Gneezy et al 2010, 2012; Kim, Natter, and Spann 2009), self-signaling (Gneezy et al 2012; Jang and Chu 2012), social norms (Reiner and Traxler 2012), reputational concerns (Kim, Kaufmann, and Stegemann 2014), customer satisfaction, and income (Kim, Natter, and Spann 2009, 2014). More recently, Stangl, Kastner, and Prayag (2017) showed that repeat customers pay more than new and potential customers for a high-priced service.…”