Abstract for:Valence Matters in Judgments of Stock Accumulation Over Time: An Intervention to Improve Blood Glucose Control and Other Global Problems

One major reasoning error of great societal relevance is the stock-flow failure, in which people often conflate a stock trend with that of the flows, incorrectly inferring that an accumulation should match the patterns of its flows. Many interventions, including the use of analogies and graphical manipulations, have been suggested to reduce this reasoning mistake with little or no success. We argue that the lack of success in some of these experimental interventions is related to superficial understanding of how basic principles of accumulation influence human reasoning. We particularly address the association between the direction of an inflow or outflow (i.e., increasing or decreasing) and the direction of its associated accumulation (i.e., increasing or decreasing) over time. We also investigate how the dynamic observation (via video demonstration) of the effects in a particular accumulation trend (e.g., increasing) can increase the accuracy of participantsí judgment of a different accumulation trend (e.g., decreasing). To demonstrate the effect of accumulation direction, we employ a common health problem: controlling blood glucose level over a time through flows of sugar consumption and insulin in the bloodstream. Implications of our findings for this common problem and other global problems are discussed.