Comments on the use of the additive factor method with mentally retarded persons: a reply to Silverman

Maisto and Jerome (1977) reported a choice reaction time (RT) study relating the rate of memory scan to level of intellectual functioning. In this study, slope and intercept values of the RT function were found to be inversely related. Silverman (1978) has raised some concern over the conclusions reached by Maisto and Jerome due to the slope-intercept relationship revealed in their study, which seemingly violates one of the underlying assumptions of the additive factor method. Data were presented from previously reported research that places a number of studies with retarded persons as subjects suspect to this violation. Possible explanations for this finding were also provided.