Abstract: This article outlines a general framework for understanding how people construct mental plans for carrying out written directions. In the framework it is assumed (a) that a mental plan consists of a hierarchy of action schemas, (b) that the hierarchy is constructed by beginning with the schema at the top level of the hierarchy, and (c) that plan construction goes on concurrently with other reading processes. Predictions made on the basis of this framework were confirmed in Experiments 1 and 2. In Experiment 1, subjects were timed while they read and carried out simple directions such as 'Press button B while light X is on.' Directions were read more quickly when they began with the action ('Press button B') than when they began with either the antecedent or the consequence of the action ('while light X is on'). In Experiment 2, this effect was reversed by changing subjects' prior knowledge of what they were supposed to do. A third experiment showed that these results are specific to the task of reading and carrying out the directions; they did not occur when subjects merely recalled the sentences.