Differential relationships were predicted for four rational forms of the tendency toward novelty experiencing (External Sensation, Internal Cognitive, Internal Sensation, and External Cognitive), which had been derived by cojoint classification of source and type of experience. Most of the predictions with respect to the variables of demographic information, social desirability, other novelty variables, self-descriptive traits, patterns of ego control, external versus internal control, interpersonal attraction, and needs proposed by H. A. Murray received support. In addition, reasonably good differentiation of the forms among themselves, and with the external variables, was obtained, especially for forms sharing neither source nor type of experience. These results provide support for the fruitfulness of the strategy of measurement, this particular conceptualization of novelty experiencing, and for the adequacy of the scales.