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.     

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.     

Critical flicker fusion in normal elderly subjects; a cross-sectional community study

Critical Flicker Fusion Thresholds (CFFTs) were measured in 644 elderly people identified from community-based general practice records, and the relationship of CFFT with age was investigated. The CFFT was measured using the method of limits with mean scores for three ascending (flicker/fusion) and three descending (fusion/flicker) presentations being recorded. The difference between the ascending and descending means was found to be significantly correlated with age (r=−0.131,P<0.001) and may reflect a reduced sensitivity of the Central Nervous System to suprathreshold flicker with increasing age. The results suggest that CFFT measurement has an important role to play in gerontological research as an objective measure of cognitive aspects of the ageing process.     

Overt integrity tests versus personality-based measures of delinquency: An empirical comparis

Erratum

Overt integrity tests versus personality-based measures of delinquency: An empirical comparis     

Psychological effects of sustained shipboard operations on U.S. Navy personnel

This study investigated the psychological and physical health status of 265 crew members on two U.S. Navy ships (a guided missile cruiser and a frigate on convoy escort duty for tankers under U.S. flag) during the Persian Gulf conflict at four time periods during combat-ready operations on a single day. Findings suggest that adaptation occurs to extreme stressors associated with sustained operations. Suggestions are made relative to measures that may minimize psychological and physical conditions that adversely affect performance under conditions of heavy stress. Report No. 89-18, supported by the Naval Medical Research and Development Command, Bethesda MD, Department of the Navy, under research Work Unit No. 63206N.M0096. The opinions expressed in this paper are those of the author and do not reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government.