Evidence against the primacy of energy conservation: Exerted force in possible and impossible handgrip tasks.

Motivational intensity theory predicts that energy investment in goal pursuit is governed by the motivation to conserve resources and that it should consequently be a function of task demand: Trying to avoid wasting resources, individuals should invest only the energy that is required for task success and should disengage if success is impossible. Three experiments tested this hypothesis assessing the force exerted in an isometric handgrip task as indicator of energy investment. The results provided mixed evidence for motivational intensity theory. Supporting the theory, exerted force increased as a function of task demand if task success was possible and was low if success was impossible. However, exerted force exceeded required force in all possible conditions and participants did not disengage if task success was impossible. A meta-analysis of published studies involving disengagement conditions revealed that preceding research on motivational intensity theory also failed to provide support for the disengagement hypothesis. Our findings demonstrate the importance of task demand for energy investment but also challenge the assumption that energy investment is primarily driven by energy conservation concerns.