Project TALENT, a large scale, long range, longitudinal study, is designed primarily to provide insights into the characteristics and development of American adolescents. In order to compare trends in test results, a comprehensive battery of Psychological, educational, and personality measures were administered to participants in the 1960, 1970, and 1975 studies. Specifically, the tests measured vocabulary, English, reading comprehension, creativity, mechanical reasoning, visualization, abstract reasoning, quantitative reasoning, mathematics, and computation. Between 1960 and 1975, performance on all language tests--vocabulary, English, and reading comprehension--dropped significantly. Reading comprehension mean scores dropped one or two percentile points. Scores in computation and quantitative reasoning also showed substantial declines. The abstract reasoning test showed gains of eleven and eight percentile points for males and females, respectively. Similarly, the creativity test showed gains for both sexes. The results of the study as well as its implications for further research are discussed. (RC)