Mental energy: Assessing the mood dimension.

Conceptualizing mental energy as a mood is impor tant, because these feelings are important to people and can influence behavior in the real world. If a person feels a lack of energy, for example, he or she is more likely to avoid physical or mental work if it is possible to do so. Alternatively, this person may seek to improve feelings of energy by eating, drinking, taking dietary supplements or drugs, sleeping, or engaging in other behaviors. Thus, the measurement of the mood of energy has importance in numerous ways, including public health, work productivity, and ultimately economic growth and productivity. Mood data have limitations, for example, self aware ness and literacy are necessary and faking is possible. The problem of faking is most salient in situations in which there is a strong motivation to fake, such as when psychological testing is used as part of an employment application. Despite these limitations, overwhelming evidence supports the validity for certain measures of the mood of energy such as the POMS vigor scale. This is not to say that mood measures are error free in all situations. Despite some error, however, validity evidence for mood measures is published in the scientific literature weekly. Future research aimed at determining the biological bases for the mood of energy, and its relationships to overlapping phenomena such as cognitive fatigue, should yield results that ultimately help us to understand how to optimize our feelings of energy.