Two experiments investigated the effects on persistence of behaviour in extinction of different training procedures, using mentally handicapped boys who were trained to place objects of different shapes into matching holes in a box for sensory reinforcers. In Experiment 1 two subjects were given three training procedures: (i) a C-C procedure, consisting of 80 trials of continuous reinforcement (CRF); (ii)a P-P procedure, consisting of 80 trials of variable ratio reinforcement (VR5); and (iii) a C-P procedure, consisting of 40 trials on CRF followed by 40 on VR5. Extinction occurred most quickly after C-C training, next quickest after P-P training. In experiment 2 with four boys, C-P training of 160 trials of CRF, followed by 120 trials of VR5, produced quicker extinction than P-P training of 280 trials of VR5 reinforcement. The implications of these results for training persistent behaviour in mentally handicapped people are discussed.