An integrated choice and response time decision field theory model: new insights on choice response times in multi-attribute, multi-alternative choice.

Decision field theory (DFT), although popular in mathematical psychology, has only recently been used in choice modelling for consumer and travel choices. A key difference that DFT has from standard choice models is that it has preference values for each alternative that update over the course of the decision-making process. This results in a different probability of picking each alternative depending on how long a decision-maker considers their alternatives. However, the computational complexities of DFT have resulted in failures to utilise its dynamic nature. Recent advances in the underlying computational methods for DFT have allowed for the calculation of the probability of choosing alternatives at any time point. Consequently, the number of preference accumulation steps can be linked to the choice response time. In the work in this paper, we develop an integrated choice and latent variable decision field theory model to predict choice responses and choice response time. We use these models to explore the confounding nature of choice response time. A key assumption within DFT and other accumulator models is that preference grows over time, contradicting a well-known result that a longer response time often indicates a less certain and hence less deterministic choice from a decision-maker. In line with DFT and preference accumulation, we find that across model results from three datasets, a longer mean response time indicates that a decision-maker appears more deterministic. However, within a decision-maker, our models suggest that fast decisions are typically more deterministic, demonstrating that a longer response time indicates a less certain decision. Whilst there is a weak correlation between choice response time and the estimated number of preference updating steps, results from multinomial logit (MNL) models suggest that DFT's time parameter performs a similar function to an MNL's scale parameter. This suggests that caution is required in interpreting the outputs from accumulator models. SYMPOSIUM IN HONOUR OF A.A.J. MARLEY Adele Diederich Jamal Amani Rad Jean-Paul Doignon Karim Kilani Konstantina Sokratous Marion Collewet Quentin Gronau Thomas Hancock Xinwei Li