Fig. 4: The basic structure of the Ott et al.³⁵ model.

a The basic layout of their model, separating the original enter decision and the leaving decision as dependent on willingness to wait parameters. b In the original model, agents probabilistically accept offers based on the initial W0 > offer and quit when the wandering W crosses the quit threshold T_WZ. c This produces an attrition bias in their model, in that with longer times-spent in the wait zone, lower initial motivations are no longer part of the distribution. In the panel, each column sums to 1 and is thus a probability distribution over the remaining initial motivations (proportion of the distribution indicated by color as specified in the colorbar). d Two example distributions drawn from the set in c. Note that the distribution remaining at 20 s time-spent is shifted relative to that available after 10 s time-spent. e The model also shows a sensitivity to sunk costs, qualitatively comparable to those seen in Fig. 2f. f The model also shows that sunk costs are increased before the value crosses from negative to positive. g–k This effect is not due to selection bias, but rather to other factors in the model. In a version where the agent accepts all deals (g), the attrition bias is reduced (h, i), but the sensitivity to sunk costs are still as strong (j), and the model still shows an increased change in p(Earn) for negative over positive values (k). Results shown are from our simulations.