Stimulus factors in aversive controls: conditioned suppression after equal training to two stimuli

Pigeons trained to peck a key for food were periodically presented with tones ending with electrical shock until tone presentation consistently suppressed ongoing pecks. Shock was then discontinued and gradients of stimulus generalization were assessed by presenting tones with frequencies above, below, and at the frequencies of those used to develop conditioned suppression. When the training tones had frequencies at 670 and 1500 cps, resulting gradients were bi-modal with peak suppression at 670 and 1500 cps. Of the other test tones, 1000 cps produced the most suppression. When the training tones had frequencies at 450 and 2250 cps, bi-modal gradients were again obtained with peak suppression to the 450 and 2250 cps tones. Of the other test tones, 1000 cps produced the least suppression. These results support the hypothesis that generalized response tendencies summate.     

A comparison of two psychophysical methods using animals

A discrimination box containing two levers with a light above each was used to train eight rats to press beneath the brighter light for a milk reinforcer. The brighter light was held constant and the comparison light was varied to produce 12 brightness differences. The animals were run under two experimental methods: the block method in which each brightness level comparison was presented for a block of 11 contiguous trials, and the staircase method in which the sequence of brightness comparisons was determined by the correctness of the response on the preceding comparison. The block method produced a smaller differential brightness threshold and a larger change in discrimination performance for stimulus magnitude changes than did the staircase method.     

The use of rats as discriminative stimuli

A FREE OPERANT PROCEDURE WAS USED TO DETERMINE WHETHER OR NOT ONE RAT COULD DISCRIMINATE: (1) between the presence and absence of a second rat, and (2) between two other rats of the same species and sex. The subjects were four male Wistar rats. The discriminatory response was a bar press and food was used as reinforcement during training. Although there were wide individual differences in rate of learning, all subjects learned to make both discriminations.     

Fixed ratio and extinction performance of infants in the second year of life

Five 14(1/2)- to 19(1/2)-month-old infants were trained to lever press for snacks on small fixed ratio schedules of reinforcement. Within four to nine sessions, responding under FR 10 was established for four subjects and FR 15 for the other. Each subject's last session revealed behavioral patterns similar to animal and human FR trained subjects-a high and constant ratio rate, mixed with a zero rate following reinforcements. Deviations were mostly in the form of prolonged and variable post-reinforcement pauses. These and other irregularities were probably due to the limited deprivation conditions and improper training procedures in which the ratio (for two subjects) was ascended too early and too quickly. Extinction was instituted during the last session. The degree to which extinction performance matched that of other organisms depended upon how stable and "ratio-like" performance was during conditioning.     

Job Satisfaction Researches of 1964–65

This annual review of job satisfaction researches is the 23rd in a series and covers reports published in 1964–65 plus earlier studies not previously dealt with in this journal. The format—findings and conclusions, topics investigated, per cent dissatisfied, current emphases, and summaries of studies—has become standard in this series of articles.     

Cognitive behavior modification: ‘Motivated learning’ reading treatment with subprofessional therapy-technicians

A method of treating reading deficits based upon an extrinsic motivational system previously employed successfully with a single subject was extended to eighteen additional subjects. The junior-high age subjects included retarded children in special classes, several emotionally disturbed children, and culturally deprived children. The method of training used in the original study was designed to be simple to administer and simple to record the performance of the child. Thus, it was hypothesized that subprofessional personnel could be employed to administer the treatment. Adult volunteers and high school seniors were used as the therapy-technicians.

The eighteen Ss were given 38.2 hr of training in daily half-hour sessions, during which period the average reinforcement earned was $22.29. The mean number of single word reading responses was 94,425. The rate of reading accelerated over the period of training even though the reading material became more difficult. This occurred during a period when progressively less (about one-fourth as much) reinforcement was given per reading response. A mean of 593.5 new words were learned and 70.9 per cent of these were retained in a long-term test. The attention, attendance, cooperation, and diligent work behavior of the various children were maintained in good strength throughout the duration of the study. The results suggest that research be conducted to develop methods for treatment of behavioral deficits that can be widely applied by subprofessional therapy-technicians supervised by clinical psychologists.