Generative models of behaviour and self-report during mind wandering

<div>Mind wandering is ubiquitous in everyday life yet unlike many cognitive activities it cannot be directly manipulated in the lab. Instead, mind wandering is typically assessed as a dependent variable with 'thought probes', infrequent self-report items enquiring about the focus of attention interspersed with items from a primary cognitive task. Despite measurement as a dependent variable, many mind wandering investigations treat thought probes as an independent variable: performance in the primary task is analysed as a function of thought probe responses. This approach violates assumptions of many conventional statistical analyses and fails to explain how people generate responses to thought probes. Here, we treat both streams of data - behavioural and self-report - as the observable outcomes of an integrated latent cognitive process. Choices and response times in two decision making studies were modelled with the Timed Racing Diffusion Model (TRDM). We structurally linked TRDM parameters to a latent 'mind wandering' continuum of a Thurstonian "strengths" model, which generated self-report responses to thought probes. The model captured all key quantitative trends in accuracy, RT and self-report data at the individual participant level. From a set of competing models, the best explanation of the data assumed that sensitivity to non-target stimuli is negatively associated with the propensity to mind wander during ongoing performance. This goes against the oft-stated though rarely modelled conclusion that mind wandering is associated with greater processing variability.</div>