Effects of pentobarbital on fixed-ratio reinforcement,

Certain doses of pentobarbital consistently increased the rate of pecking engendered by a fixed-ratio schedule of 30 responses in a group of 13 pigeons, and still higher doses produced decrements in rate of responding. For individual subjects, the dose-effect functions were qualitatively similar, but differed with respect to the doses producing the maximum increase and subsequent decrease in rate. In general, the maximum occurred at lower doses and the decrement was greater at the highest dose in the birds with the highest control rates. It was also possible to distinguish between the effects of pentobarbital and several other drugs on the behavior maintained by FR 30. The results indicate that changes in rate of responding on FR 30 after drug administration are dose-dependent, drug-specific effects.     

Generalization of auditory intensity as a function of small amounts of discrimination training

Rats were trained on a two-valued auditory-intensity discrimination for 5, 2, 1 or 0 days. Then, the bar-press response rate was sampled in the presence of seven added discrimination stimuli (generalization) for seven days. Daily training sessions were 4 hr in length throughout the experiment. Only the five-day group exhibited a marked superiority on the multi-valued discrimination when contrasted with the group having had no prior simple discrimination training.     

Punishment of SΔ responding of humans in conditional matching to sample by time-out

Human subjects were intermittently reinforced with money for performing correctly on a conditional matching-to-sample task. The matching performance was examined as a function of a) the duration of Time-Outs (TOs) which followed every incorrect response and b) the frequency (FR value) with which TOs followed incorrect responses. The matching accuracy increased with longer TOs and decreased with less frequent presentation of TOs.     

Persistent behavior maintained by unavoidable shocks

Squirrel monkeys were trained on a multiple schedule in which 10-min periods on a continuous shock avoidance schedule, indicated by a yellow light, alternated with 10-min periods on a 1.5-min variable interval schedule of food reinforcement (VI 1.5). A white light indicated that VI 1.5 was in effect, except for the middle 2 min of the period on VI 1.5, in which a blue light appeared and terminated with the delivery of a 0.5-sec unavoidable shock. Stable response rates developed in the avoidance and VI 1.5 components. However, the highest response rates occurred in the blue, preshock stimulus. A series of experiments showed that responding in the blue stimulus persisted even when responding had been extinguished on both the VI schedule of food reinforcement and the shock avoidance schedule. Responding in the blue stimulus ceased when the blue stimulus terminated without shock or when it terminated with a response-contingent shock. Each time responding ceased, it was restored by terminating the blue stimulus with an unavoidable shock. When the blue stimulus was on throughout each session and unavoidable shocks were delivered at regular 10-min intervals, responding was well maintained. These results show that in monkeys that have been trained on a continuous avoidance schedule, unavoidable shocks can maintain responding even under conditions where responses have no programmed consequences.     

The effect of two schedules of primary and conditioned reinforcement

Of 23 pigeons, 11 received continuous reinforcement for key pecking, and 12 received an FR 10 schedule of reinforcement. The birds were then tested without food, but with potential conditioned reinforcers presented either on the same schedule as in training, on the other schedule, or not at all. Each bird in the subgroup trained on CRF and tested with S^r's at FR 10 not only gave more responses in testing than did each bird in both subgroups receiving no S^r's, but also gave more responses than did each bird in the S^r subgroup receiving CRF training and S^r's at CRF. Cumulative records are presented to show the effects of different schedules of conditioned reinforcers.     

Simulation of human problem-solving behavior

In the simulation of human behavior on a digital computer, one first attempts to discover the manner in which subjects (Ss) internally represent the environment and the rules that they employ for acting upon this representation. The interaction between the rules and the environmental representation over a period of time constitutes a set of processes. Processes can be expressed as flow charts which, in turn, are stated formally in terms of a computer program. The program serves as a theory which is tested by executing the program on a computer and comparing the machine's performance with S's behavior.