Many types of behaviour have a temporal aspect-it does not matter just what actions are taken, but in what order they are taken. This is true of everyday motor tasks, such as getting dressed or driving a car, as well as being central to all types of linguistic behaviour. The need to deal with the serial ordering of responses is thus of great importance to much of psychology. Yet historically the issue of serial order has received relatively little attention from the cognitive sciences. In a seminal paper of 1951, Karl Lashley described what he termed “the problem of temporal integration” as “the most important and also the most neglected problem of cerebral physiology” (Lashley, 1951, p. 508). Over more recent decades this neglect has persisted, encouraged no doubt by the ease with which sequence processing may be achieved with conventional computer programming languages. This has tended to fuel a perception amongst cognitive scientists that “the problem of serial order” has been solved or is trivial, and attention has tended instead towards those areas of cognition which are diﬃcult to address using conventional serial computer techniques.