Methodological dilemmas in the use of time as a variable in developmental psychology

The temporal dimension of developmental psychology can be the source of numerous errors committed in making inferences about development. In the present paper the author described the time traps into which a researcher may fall while examining developmental changes at three different stages of his/her scientific investigation: (1) operationalization of variables; (2) sampling; (3) inferring. The mentioned traps are inextricably connected with the temporal relativity of the reliability of the measurement of variables in cross-sectional and longitudinal studies; the temporal character of a sample, the composition of which changes in the process of longitudinal and sequential studies as well as the theoretical assumptions on the notion of time, which are fundamental for our understanding of developmental changes.