this tendency of buyers to indicate lower prices is their risk aversion. By contrast, sellers may assume that the market is heterogeneous enough to include buyers with potential risk neutrality and therefore adjust their price closer to a risk neutral expected value. Biased information processing theories Several cognitive accounts of the endowment effect suggest that it is induced by the way endowment status changes the search for, attention to, recollection of, and weighting of information regarding the transaction. Frames evoked by acquisition of a good (e.g., buying, choosing it rather than another good) may increase the cognitive accessibility of information favoring the decision to keep one's money and not acquire the good. By contrast, frames evoked by disposition of the good (e.g., selling) may increase the cognitive accessibility of information favoring the decision to keep the good rather than trade or dispose of it for money (for a review, see Morewedge & Giblin, 2015). For example, Johnson and colleagues (2007) found that prospective mug buyers tended to recall reasons to keep their money before recalling reasons to buy the mug, whereas sellers tended to recall reasons to keep their mug before reasons to sell it for money. Evolutionary arguments Huck, Kirchsteiger & Oechssler (2005) have raised the hypothesis that natural selection may favor individuals whose preferences embody an endowment effect given that it may improve one's bargaining position in bilateral trades. Thus in a small tribal society with a few alternative sellers (i.e. where the buyer may not have the option of moving to an alternative seller), having a predisposition towards embodying the endowment effect may be evolutionarily beneficial. This may be linked with findings (Shogren, et al., 1994) that suggest the endowment effect is less strong when the relatively artificial sense of scarcity induced in experimental settings is lessened. Countervailing evidence for an evolutionary account is provided by studies showing that the endowment effect is moderated by exposure to modern exchange markets (e.g., hunter gatherer tribes with market exposure are more likely to exhibit the endowment effect than tribes that do not), and that the endowment effect is moderated by culture (Maddux et al., 2010). Criticisms Some economists have questioned the effect's existence. Hanemann (1991) noted that economic theory only suggests that WTP and WTA should be equal for goods which are close substitutes, so observed differences in these measures for goods such as environmental resources and personal health