With the exception of studies such as Glass and Singer's (1972) that concern momentary changes in a person's sense of control, the larger number of investigations discussedlhus far contain descriptions of locus of control that make it appear as if -t were a stable attribute. Especially in view of the longitudinal data discussed in the preceding chapter, the reader may presume that the locus of control construct is viewed as a trait or even as a typology by its users. With subjects commonly classified as internals or externals, it could not be argued that this impression is a gross misinterpretation. The difficulty, however, inheres less in the construct itself than in our language, which encourages concision on the one hand and an animate subject within each sentence on the other. If group differences are to be described, the more accurate phrasing, "those who repon (on a given scale) that they perceive events as being largely contingent upon their personal efforts at the present time, as opposed to those who feel more fatalistic about the manner in which outcomes occur, " would prove to be too cumbersome to allow for concise expression. Consequently, we are more often confronted with statements suggesting that there are people who are internals and others who are externals who will, as a result of these identities, differ on any number of associated dimensions. It is one purpose of this chapter to attempt to dispel this ready perception of locus of control as a trait, or worse, a typology with all the connotations of intractability and fixedness that those terms imply.