[Effort--a form of self-imposed stress]

Effort is analyzed as a top-down process which is a feature of autonomous work procedures. A rise in effort may affect different aspects of efficiency in performance: (a) Increment in speed, (b) increment in accuracy, (c) shifts in difficulty level, (d) focus on central aspects of the task. A "law of diminishing returns" is postulated which calls for a balanced utilization of all options. In an experiment, subjects worked in a simulated office environment. The main independent variables were high-effort vs. low-effort instructions, and assignment vs. free choice of tasks. The subjects were also grouped according to their scores in an intelligence and an anxiety test. The results confirm the general expectation that a rise in effort may affect performance in terms of speed, accuracy, choice of difficulty level, and focus. However, the result vary considerably with experimental conditions and personality variables. Apparently, effort imposes a mental and emotional load which is best coped with by the low anxious and high intelligent.