Task scenarios and thought

The position that scenarios are low fidelity task simulations and can be understood from a broadly defined, performance based perspective of task analysis is one that is defended. It is argued that scenarios used for engineering purposes are impoverished in comparison with the sort of properties enjoyed by good stories and that the metaphor of scenarios as stories is one of limited utility. A general psychological theory that thought can be described as envisioned scenarios is espoused and that this will be generally useful to non-psychologists and facilitate the understanding of the limitations of scenarios as used for the purposes of scenario-based design.