DescriptionThis study investigated the contribution of task constraints to planning processes and outcomes across four tasks which contained varying numbers of spatial and temporal constraints. Verbal protocols were obtained during forty-five young adults' planning of the four tasks. Participants' conceptualizations in terms of space or time, and their focus on sequencing task elements during planning were clearly related to the spatial, temporal and order constraints in the tasks. Participants were very consistent in the degree to which they focused on time and the amount of verbalizations across tasks, and they were somewhat consistent in their focus on sequencing. They were not consistent in their focus on space. Of the planning outcomes investigated, constraint violations on tasks were related to the proportion of implicit constraints, spatial and temporal efficiency were related to spatial and temporal constraints, and total verbalizations were related total constraints in the tasks. Individual participants' planning outcomes were not related across tasks. The degree to which participants focused on location during planning of a task with mostly spatial constraints was related to spatial efficiency of their plan, this relationship was not seen in a task with spatial and temporal constraints. Various cognitive abilities of were measured, verbal and visuospatial working memory, verbal and nonverbal fluency, processing speed, updating, shifting and inhibition. One measure of visuospatial memory as well as nonverbal fluency was related to the degree to which participants focused on sequencing actions. The results indicate that planning processes are somewhat general, and that planning processes and outcomes vary with constraints contained in planning tasks. It is suggested that conceptualizing planning tasks in terms of constraints allows for valuable comparison across tasks.