Nathaniel J. S. Ashby

Forgetting the past: Individual differences in recency in subjective valuations from experience.

Recent research investigating decisions from experience suggests that not all information is treated equally in the decision process, with more recently encountered information having a greater impact. We report 2 studies investigating how this differential treatment of sequentially encountered information affects subjective valuations of risky prospects when observations of past outcomes must be used to estimate the prospects payoff distribution, and examine how individual differences in cognitive capacities influence information usage. In Study 1 we found that a sliding window of information model that averages a subset of (only) the most recently encountered outcomes (samples) fit the subjective valuation data for a portion of individuals better than models that integrate all observed outcomes. This pattern of results is replicated in Study 2, in which we also found that the amount of information used to form valuations varies greatly between individuals, and that individual difference in memory span explains a portion of this variation. Combined, these results suggest a process in which information usage is in part reliant on cognitive capacity, and where information aggregation appears to be memory based rather than online, providing new insight into the processes involved in the construction of valuation in experiential decisions.

Conscious and Unconscious Thought in Risky Choice: Testing the Capacity Principle and the Appropriate Weighting Principle of Unconscious Thought Theory

Daily we make decisions ranging from the mundane to the seemingly pivotal that shape our lives. Assuming rationality, all relevant information about one’s options should be thoroughly examined in order to make the best choice. However, some findings suggest that under specific circumstances thinking too much has disadvantageous effects on decision quality and that it might be best to let the unconscious do the busy work. In three studies we test the capacity assumption and the appropriate weighting principle of Unconscious Thought Theory using a classic risky choice paradigm and including a “deliberation with information” condition. Although we replicate an advantage for unconscious thought (UT) over “deliberation without information,” we find that “deliberation with information” equals or outperforms UT in risky choices. These results speak against the generality of the assumption that UT has a higher capacity for information integration and show that this capacity assumption does not hold in all domains. Furthermore, we show that “deliberate thought with information” leads to more differentiated knowledge compared to UT which speaks against the generality of the appropriate weighting assumption.

Who's biased? A meta-analysis of buyer-seller differences in the pricing of lotteries

A large body of empirical research has examined the impact of trading perspective on pricing of consumer products, with the typical finding being that selling prices exceed buying prices (i.e., the endowment effect). Using a meta-analytic approach, we examine to what extent the endowment effect also emerges in the pricing of monetary lotteries. As monetary lotteries have a clearly defined normative value, we also assess whether one trading perspective is more biased than the other. We consider several indicators of bias: absolute deviation from expected values, rank correlation with expected values, overall variance, and per-unit variance. The meta-analysis, which includes 35 articles, indicates that selling prices considerably exceed buying prices (Cohen’s d = 0.58). Importantly, we also find that selling prices deviate less from the lotteries’ expected values than buying prices, both in absolute and in relative terms. Selling prices also exhibit lower variance per unit. Hierarchical Bayesian modeling with cumulative prospect theory indicates that buyers have lower probability sensitivity and a more pronounced response bias. The finding that selling prices are more in line with normative standards than buying prices challenges the prominent account whereby sellers’ valuations are upward biased due to loss aversion, and supports alternative theoretical accounts.

When time is (not) money: preliminary guidance on the interchangeability of time and money in laboratory-based risk research

The familiar adage that ‘time is money’ may not be entirely accurate according to research involving hypothetical choice: People’s decisions are less sensitive to temporal expenditures and outcomes than monetary ones. We provide a novel examination of whether similar patterns of risky choice are found for time and money when choices are consequential (i.e. monetary outcomes are obtained and temporal outcomes are experienced) – both for one-shot and repeated choices, over gains and losses. On the aggregate, across decision contexts (described and experienced), choices are similar for time and money. However, on the level of the individual, little relationship between risk preferences for time and money are observed. We discuss the theoretical and practical implications of these findings.

Are we attracted by losses? Boundary conditions for the approach and avoidance effects of losses.

The majority of the literature on the psychology of gains and losses suggests that losses lead to an avoidance response. Several studies, however, have shown that losses can also lead to an approach response, whereby an option is selected more often when it produces losses. In five studies we examine the boundary conditions for these contradictory approach and avoidance effects. The results show that an approach response emerges only when losses are produced by a highly advantageous choice alternative and when participants have ample unbiased direct or vicarious experience with this alternative. Additionally, the avoidance response to losses is also not ubiquitous and emerges when alternatives producing losses are experienced as disadvantageous. Thus, the findings suggest that both the approach and avoidance effects of losses exist and can be accounted for by increased investment of cognitive resources with losses (i.e., loss attention). Additionally, the findings clarify the loss attention account in indicating that losses increase exploitative behavior based on experienced outcomes, a process which can be locally optimal.

On the relation between economic bubbles and effort gaps between sellers and buyers: An experimental study

Economic bubbles are an empirical puzzle because they do not readily fit the notion of an efficient market. We argue that bubbles are associated with a conflict and a gap in the allocation of effort during negotiation by sellers and buyers. We examined 21 experimental asset markets where in one condition players could buy and sell and in the other they could either buy or sell. The results indicated that when making concurrent buying and selling decisions the mean number of asks for sellers was 71% higher than the number of bids for buyers. Similar findings emerge in a re-analysis of data from Lei et al. (2001). Importantly, bubbles only emerged in markets where the number of asks was larger than that of bids. These findings indicate that bubbles are associated with increased negotiation effort when acting as a seller and diminished effort when acting as a buyer.