Capacity and Capability

This article reports evidence from seven different studies reflecting on the capacitylcapability hypothesis. This hypothesis states that certain aspects ofperformance (such as rate) on later trials can be predicted from the way in which participants experience difficulty on an initial trial. Difficulty can be experienced as a problem of capacity-having too much to do, or too little time to do it in. An initial capacity problem leads to a faster rate of performance on later trials in order to overcome that quantitative difficulty. Difficulty can also be experienced as a problem of capability-the items of the task themselves challenge the processing capability of the performer. An initial capability problem leads to a slower rate of performance on later trials in order to overcome that qualitative difficulty. The studies reported in this article are of varying task types (three are intellective or problem-solving, two are creativity, and two are planning tasks); varying group sizes (individuals, dyads, and triads); and varying time limits over multiple trials. Convergent evidence from three types of dependent variables (rate measures, cumulative solution curves, and self-report data) are used to support the capacity/capability hypothesis.