Development of social responses in two severely retarded children

The effect of reinforcement dependent on the social responses of two severely retarded withdrawn children was investigated. During 30 training sessions (30 min each) food and praise were administered dependent upon the children's mutual participation in a ball-rolling and block-passing task. Both children showed a progressive increase in social interaction in a non-training situation during this reinforcement period. After the reinforcement procedures were removed, social behavior decreased markedly. Response generalization to children not involved in training occurred.     

Tactile short-term memory

Subjects tried to recall the location of a tactile stimulus on the underside of the forearm after delays of 0, 3, 5, 10, 15, 30, 45 and 60 sec. When “rehearsal” was prevented by requiring subjects to count backwards during the delay, accuracy of recall decreased systematically reaching an asymptote after 45 sec. When subjects were left free to “rehearse,” this did not affect the decline in accuracy over the first 10 sec. Between 10 and 15 sec. there was a significant increase in accuracy followed by a slow decline which had not reached asymptote by 60 sec. It is suggested that tactile STM (short-term memory) depends on two processes, a fading sensory trace which is unaffected by distraction and a less labile system which does not appear to be verbal but which depends on “rehearsal.”