ABSTRACT
Introduction This chapter is all about the measurement of states. Unlike traits, states are not stable, constant features of individuals as are (for example) extraversion and verbal ability. Instead, states are highly volatile, changing from hour to hour or from minute to minute, often (although not necessarily) in response to life events. Two broad classes of state have been identified, namely mood states and motivational states. Moods are the familiar surges of emotions that we feel on the morning of an examination, on seeing a beautiful sunset, on viewing a moving performance on stage or screen or after seeing our team win an important match. Some theorists draw distinctions between moods and emotions, but I have suggested elsewhere that this is a dangerous practice (Cooper 1997). Motivational states are internal feelings that drive us to eat when hungry, to spend hours assuaging our social conscience through voluntary work, to spend time and money finding a partner and so on.
