A computer model is presented which performs four different types of tasks sometimes impaired by frontal damage: the Wisconsin Card Sorting Test, the Stroop task, a motor sequencing task and a context memory task. Patterns of performance typical of frontal-damaged patients are shown to result in each task from the same type of damage to the model, namely the weakening of associations among elements in working memory. The simulation shows how a single underlying type of damage could result in impairments on a variety of seemingly distinct tasks. Furthermore, the hypothesized damage affects the processing components that carry out the task rather than a distinct central executive responsible for coordinating these components.