Both response proportion and response time (RT) measures were obtained in a task requiring temporal order judgements (TOJ) of the illumination of two lights. The decrease in mean RT as the inter‐stimulus interval increased enabled the deterministic decision rule for TOJ to be rejected. Although the data were not inconsistent with a decision process incorporating a threshold for temporal resolution, a model based on a random walk process accounted for important features of the data. The implications of these results for the commonly employed “perceived‐order” method are di