Toward a psychological theory of multidimensional activation (arousal)

The traditional physiologically defined activation or arousal continuum, which ranges from intense emotion and vigorous activity on one extreme to calmness and sleep on the other, is rejected in favor of a psychological model with two activation dimensions and a single continuum of energy expenditure. One activation dimension ranges from subjectively defined feelings of energy and vigor to the opposite feelings of sleepiness and tiredness. Activation states associated with this dimension regularly vary in a circadian rhythm, and this dimension underlies gross physical activity and many aspects of cognition. The second dimension ranges from subjective tension to placidity and quietness, and it probably underlies a variety of emotions (e.g., anxiety) and stress reactions (e.g., effects of loud noise). While the two dimensions are positively correlated at moderate levels of energy expenditure, they are negatively correlated at high levels of expenditure; therefore, tension is lowest when energy-vigor is greatest and vice versa. Vulnerability to tension increases at late night, early morning, and at other times when effort and stress have increased tiredness and reduced vigorousness. Extremely low activation on either dimension de-energizes the whole system. Although only two dimensions are assumed, the possibility of four or more activation dimensions is discussed.I am grateful to Carolyn Thayer, Leonard Hommel, John Jung, Lyle Creamer, and Kenneth Armbruster for reading and commenting on an earlier version of this paper. I also wish to thank David McCarty for his aid in collecting and reducing data for Study 1. Finally, thanks are due to David Payne for his contributions of thermometers for Study 1 and literature retrieval services for other aspects of this work.