Behavioural Energetics: Some Effects of Uncertainty on the Mobilization and Distribution of Energy


  • The work I shall report was done in collaboration wiih a number of my students and colleagues, I would particularly like 10 thank Keith Phillips, Andrew Sherwood, Doug Moncur, Gena Connally, Jennifer Moses. Sam Connally, and Suzanne Mitchell, whose research I have drawn on in preparing this lecture. Thanks arc also due lo our technical staff: Ray Wallis. Clive Welbourne, Sandra Readhead, Bob Richman. and Mark Hulchinson, without whose expert assistance the work could not have been executed. Finally. 1 would like to thank my recent Special Optionists, Paul Chung, Sarah Dilks. Jim Freund, Heather Harper. George Medley. Sarah Mossman, Stephanie Oakley, Christopher Ring, and Anne Rockctt. who spent many hours with me, patiently discussing the matters raised here and running experiments.

Address requests for reprints to Jasper Brener, who is now at the Department of Psychology, State University of New York at Stony Brook, Stony Brook, New York 11794.


Several sets of data illustrating dissociation of metabolic and muscular work rates are presented. During response acquisition, the rate of energy expenditure declines although work rates remain constant and goal achievement increases. When higher response costs are demanded for goal achievement, work rates increase whereas energy expenditure remains constant. Decreases in outcome probability also give rise to increases in motor intensity and work rate but do not influence the rate of energy expenditure. It is proposed that behaviourally-related variations in metabolic rate are influenced by environmental uncertainty (“what to do”), whereas variations in the intensity of motor output are influenced by response uncertainty (“how to do it”). The processes of response selection which provide the means by which response uncertainty is resolved, activate motor channels for the expression of energy mobilized by the prevailing state of environmental uncertainty.