Studies of reflection-impulsivity (RI) suggest that the tendency is correlated with performance on a variety of similar tests. They predict the quality of problem solving under conditions of response uncertainty, except in the case of preschoolers who have not yet learned to delay and scrutinize alternative hypotheses. It is noted that the response time component of RI is relatively independent of IQ, whereas the error component is moderately related. Shortcomings of the major test (the Matching Familiar Figures Test) used to measure RI are described, and norms to guide the researcher are presented. Studies of scanning behavior show that reflectives gather more information more carefully and systematically than do impulsives. Attempts to relate this variable to personality and social variables have been only partially successful. RI is related to certain clinical syndromes including hyperactivity, brain damage, epilepsy, and mental retardation. It also affects school performance, as evidenced by the greater impulsivity of children with reading difficulties, learning disabilities, and school failure. Impulsivity has been found to be modifiable: The most consistently successful strategy in this regard is to teach impulsives improved scanning strategies by means of appropriate training materials while having them verbalize such strategies aloud. (3 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)