The effect of observing response procedures on the reduction of over-selectivity in a match to sample task: immediate but not long term benefits.

Stimulus over-selectivity occurs when only one of potentially many aspects of the environment comes to control behavior. In three experiments, adult participants with no developmental disabilities were trained and tested in a match to samples (MTS) paradigm. Participants in Experiment 1 were assigned to one of two conditions, which differed on whether an observing response procedure was in place. Findings indicated that an MTS procedure can induce over-selectivity in this population if a time delay is included between sample and comparison. Over-selectivity emerged significantly more in the group who did not use an observing response procedure. In Experiments 2 and 3, participants were exposed to a re-test phase, in which the initial stimuli were presented again, but without the use of an observing response in either group. The observing response procedure only reduced over-selectivity when in place, but performance did not remain high following its withdrawal. This effect was noted regardless of the type of observing response procedure used (pointing versus naming). These findings suggest that an observing response procedure may be effective in reducing over-selectivity, however, these effects do not last post intervention, and that this may limit the clinical usefulness of the technique.