The verbal and cognitive effects of both a Toy Demonstrator and a similar home visitor who abstained from stimulation techniques were studied in the Verbal Interaction Project. Three groups of children, totalling 54, participated in the study from July 1967 through June 1968. One group received "double intervention" (Toy Demonstrator), another received "single intervention" (home visitor), and a third group received no intervention. All groups received psychological testing before and after the seven-month experimental intervention period. The experiment and results confirmed the ability of the Mother-Child Home Program to raise significantly the initially low mean verbal and general IQ's of the children exposed to "double intervention." The Toy Demonstrators used in this program were trained and experienced social workers; however, nonprofessionals personnel were trained to assume Toy Demonstrator role. Two groups were given training--family agency volunteers, and women who had been mother-participants. The effects of using nonprofessionals have not been evaluated. (DB)