The purposes of this study were to: (1) examine the psychometric properties of the Ball Aptitude Battery (BAB) on a high school freshman sample; (2) develop BAB norms for high school freshmen; (3) develop and evaluate four memory tests and a vocabulary test appropriate for freshmen; (4) examine level and structure differences for the BAB tests across race and sex groups within the freshman sample; and (5) examine the differentiation hypothesis. Subjects were 445 freshmen from nine Chicago area high schools. Results indicated that: (1) except for the vocabulary test which is too difficult, the BAB has adequate psychometric properties with a freshmen sample; (2) all the memory tests warrant further development for possible inclusion in the BAB; (3) level differences across race and sex groups in the freshmen sample were in expected directions, but two distinct factor patterns appeared. Because clear differences in both level and structure were found between high school freshmen and seniors, separate freshman norms were constructed. Further research is needed before conclusions can be made on the differentiation hypothesis. (Author/BS)