Considerations of energy investment as determinants of behaviour. Paper presented at the Symposium held in Amsterdam, September 1969, sponsored by the International Ergonomics Association.

If a human being is accepted as a limited energy input system and excessive demands for energy constitute stress it becomes evident that measurements should be applied which, in fact, examine the total energy demands made upon human operators, both physical and mental. In this period of increasing time compressed operations like supersonic transport, high speed ground transportation systems etc. the consequences of operator failure can be catastrophic.