Polydipsia induced in the rat by a second-order schedule

Drinking was studied in rats pressing a bar on a second-order schedule in which every third completion of a 1-min fixed interval was followed by food presentation. A brief flash of light signaled the completion of each fixed-interval component. The rats drank not only after the food presentations but also after presentations of the light flash alone. A high rate of steady drinking followed intervals terminated by a food presentation. Drinking that followed intervals terminated by a light flash alone was of comparable rate, but characteristically interrupted by bar pressing. When 250-mg food pellets were used instead of 45-mg pellets, both drinking and bar-pressing rates increased substantially.     

The Association for Human Development: a revitalized APGA

The American Personnel and Guidance Association faces a time of challenge as it moves increasingly to a world of change and innovation. Unfortunately, the divisional structure and emphasis of the Association as presently conceived builds for divisiveness, and little organizational unity is evident. However, all members in APGA are concerned with human development, maximizing individual potential, and helping individuals profit from developmental tasks involved in living. The Association for Human Development is suggested as a new name for APGA. Conceptual models for the divisions of the Association are suggested which imply the unity of the developmental process.     

Longitudinal factor analysis

A model is presented for factor analysing scores on a set of psychological tests administered as both pre- and postmeasures in a study of change. The model assumes that the same factors underlie the tests on each occasion, but that factor scores as well as factor loadings may change between occasions. Factors are defined to be orthogonal between as well as within occasions. A two-stage least squares procedure for fitting the model is described, and generally provides a unique rotation solution for the factors on each occasion.We thank M. W. Browne, R. P. McDonald, R. Pruzek, and the Managing Editor for their constructive comments.