Two studies examined modifiability in intellectual functioning in older adults. The fluid-crystallized theory provided a theory base for the research. (Fluid intelligence follows a normative decline through adulthood, while crystallized intelligence remains stable or even increases.) In the first study thirty subjects (average age 69.2) participated in eight practice (retest) sessions, at which they were administered two tests involving figural relations and induction. Although no external feedback was given during retest sessions, subjects exhibited steady gains between consecutive trials. In the second study fifty-eight subjects (average age fifty-nine) participated in five training sessions on strategies for solving figural relations-type problems. Maintenance of training effects over three posttest periods and generalizability of training across seven measures were used to assess the training. Mean scores for the training group were larger than the control's scores for all seven measures at each posttest occasion. Findings that subjects possessed or were able to generate cognitive strategies useful in improving their fluid intellectual performance and that training effects extended beyond the target ability imply the potential for modifiability in intellectual functioning in middle and later adulthood and suggest that comprehensive theories of intelligence including both potential and normative dimensions of functioning may be particularly important in adulthood. (MN)