graphical form. In the figure, two indifference curves for a particular good X and wealth are given. Consider an individual who is given goods X such they move from point A (where they have X0 of good X) to point B (where they have the same wealth and X1 of good X). Their WTP represented by the vertical distance from B to C, because (after giving up that amount of wealth) the individual is indifferent about being at A or C. Now consider an individual who gives up goods such that they move from B to A. Their WTA represented by the (larger) vertical distance from A to D because (after receiving that much wealth) they are indifferent about either being at point B or D. Shogren et al. (1994) has reported findings that lend support to Hanemann's hypothesis. However, Kahneman, Knetsch, and Thaler (1991) find that the endowment effect continues even when wealth effects are fully controlled for. Figure 2 : Hanemann's Endowment Effect Explanation When goods are indivisible, a coalitional game can be set up so that a utility function can be defined on all subsets of the goods. Hu (2020) shows the endowment effect when the utility function is superadditive, i.e., the value of the whole is greater than the sum of its parts. Hu (2020) also introduces a few unbiased solutions which mitigate endowment bias. Connection-based, or "psychological ownership" theories Connection-based theories propose that the attachment or association with the self-induced by owning a good is responsible for the endowment effect (for a review, see Morewedge & Giblin, 2015). Work by Morewedge, Shu, Gilbert and Wilson (2009) provides support for these theories, as does work by Maddux et al. (2010). For example, research participants who were given one mug and asked how much they would pay for a second mug ("owner-buyers") were WTP as much as "owners-sellers," another group of participants who were given a mug and asked how much they were WTA to sell it (both groups valued the mug in question more than buyers who were not given a mug). Others have argued that the short duration of ownership or highly prosaic items typically used in endowment effect type studies is not sufficient to produce such a connection, conducting research demonstrating support for those points (e.g. Liersch & Rottenstreich, Working Paper). Two paths by which attachment or self-associations increase the value of a good