Is bar-holding with negative reinforcement preparatory or perseverative

Three of four white rats learned to press first one bar and then another to escape or avoid electric shocks. Cumulative bar-holding-time records showed that holding occurred frequently on the second bar but hardly ever on the first, indicating that bar-holding is more "perserverative" than "preparatory". The response chain, first-bar press second-bar press, was more easily established by a forward than by a backward chaining procedure.

Water maze savings by mice as a function of motor training

Mice given either 0, 4, 8, or 12 trials of motor training (practice swimming) in a water tank showed appreciable savings during the early trials of acquisition training in a water maze. Differences in escape latency and error savings for this task were related to the amount of prior motor training.

Interaction between reflexive fighting and cooperative escape

Subjects separated by a Plexiglas partition were trained to follow a cooperative escape procedure which produced behavior like the escape responding of individual subjects. Removal of the partition produced fighting and less efficient escape. Efficient escape behavior was restored and fighting disappeared when the partition was replaced. Neither increased space nor a moving toy affected escape behavior. The results indicate that switching animals from an isolated to a social situation produced a change in the effect of shock upon escape which was related to shock-induced fighting.

A rat chamber and electrode procedure for avoidance conditioning

A method was developed for studying the reactions of rats to aversive shock. The distinctive features were the design of the chamber and a method of restraint that allowed the use of surface electrodes to deliver the shock. Advantages of this method were: (1) accurate specification of the shock actually received by the rat; (2) elimination of all unauthorized escape or avoidance reactions; (3) elimination of the shock scramblers and floor grids required with foot-shock; and, (4) rapid acquisition of performance under various avoidance procedures and various frequencies of shock delivery.