Stopping and response control : application of a novel tracking task

Stopping a planned or ongoing action is one of the central methods for examining response control and inhibition. This research area has been dominated by the application of the "stop-signal paradigm" which measures the inhibition of a planned action (Chapter 1). Chapter 2 describes two experiments on the development and initial testing of my novel tracking task which measures the inhibition of an ongoing action. Over the next three chapters this tracking task is used to examine three fundamental assumptions of stopping research. The first assumption is that all forms of stopping are mediated by a common mechanism. The investigation reported in Chapter 3 supports this idea as the classic stop-signal task and the novel tracking task are shown to tap into the same inhibitory mechanism. The second assumption is that stopping is governed by different constraints than those governing response initiation. Chapter 4 reports two experiments that argue against this position, as stopping and response initiation are found to be influenced similarly by manipulations to stimulus-response compatibility. The third assumption is that stopping generalizes to other measures of response modification. Chapter 5 reports three experiments that support this third assumption, with expectancy effects having a comparable influence on response inhibition and acceleration. These data also provide converging evidence for a rejection of the second assumption that stopping is unique. Chapter 6 concludes with a summary and integration of the main findings, an exploration of the practical and theoretical implications of the work, and finally, a consideration of some outstanding questions and future directions in the field of response control and inhibition.Arts, Faculty ofPsychology, Department ofGraduat