“…Performance on the reversal oddity paradigm was, in fact, retarded by experience with previous problems, a finding similar to those obtained by Gollin (1964) and Saravo and Kolodny (1969). This finding, together with the strong cross-problem interference effects that occurred, supports the hypothesis that younger children have difficulty inhibiting a previously learned response (Gollin & Saravo, in press;Saravo, 1967) and that, at least up to a certain point, practice increases their difficulty. This does not rule out the possibility that under prolonged and extensive training conditions such as those employed by House and Zeaman (1963) these effects would be overcome.…”