Extending the Failure-to-Engage theory of task switch costs.

Failure-to-Engage (FTE, De Jong, 2000) theory explains slowed response time after switching tasks as in part due to participants sometimes failing to prepare. Brown et al. (2006) rejected FTE because, in an alternating-runs paradigm, they did not observe fixed crossing point between response-time distributions that it predicts. We replicated these findings in a cued-task paradigm that allowed us to separately examine the effects of response-to-target interval and cue-to-target interval. These results guided an extension of FTE that was tested in a further experiment and shown to be able to accommodate the effects of the interval manipulations as well as both task and cue switching. We then apply a new modeling approach to obtain direct estimates of the probability of preparation and conclude that De Jong's insights about preparation failure provide a tractable framework that can explain aspects of all of the four major task-switching phenomena identified by Monsell (2003).