Uncertainty and social comparison

Two experimetnal tests were conducted of a model which predicts social comparison choices of extreme scores on a personality inventory. In groups of nine, subjects completed a bogus personality inventory that ostensibly measured a desirable or undesirable trait, and were told that either the highest or the lowest obtained score was a positive instance of the trait. The highest score was located for the subjects either with certainty or uncertainty, and the two experiments employed different manipulations of this factor. In both experiments the pattern of subjects' social comparison choices of other subjects' scores was fit best by a model comprising main effects of each factor and interactions between desirability and positive instance and between desirability and certainty.     

Effects of receptive language training on receptive and expressive language development

The effects of a six-month training program in receptive language on receptive and expressive language development were investigated. Developmentally retarded preschoolers were pretested and posttested on one standardized test of receptive language and two tests of expressive language. Both the training and control groups participated in a preschool program. In addition, the training group received a two-sequence training program: (1) reinforcement for matching responses to modeling cues and accompanying verbal requests, and (2) reinforcement for appropriate responses to verbal requests alone. The training group demonstrated a significant increase in appropriate responses to verbal request over base-rate performance after the training and also demonstrated a significantly improved posttest performance on one test of expressive language as compared to the control group.The authors wish to thank Mrs. Helen Huggins and the staff of the Aid to Retarded Children's Preschool Training Center, San Francisco, California, for their assistance in this study. A modified version of this paper was presented at the Gatlinburg Conference on Mental Retardation, March, 1974, Gatlinburg, Tennessee.     

Iterative inverse factor analysis—A rapid method for clustering persons

By interchanging persons and items, iterative inverse factor analysis provides a relatively inexpensive way of clustering persons according to their patterns of response to the items. In addition to permitting the clustering of large numbers of persons, the technique enables one to determine the bases for such clustering. The items of behavior used can be heterogeneous in content and form.     

Effects of averaging data during stimulus generalization

Rats were trained to press two keys consecutively for reinforcement. During stimulus one (slow clicker) a 6-sec time delay was required between the two responses. During stimulus eight (fast clicker) no time delay was required between the two responses. When tested with intermediate stimuli (intermediate click rates) the median time delays emitted by the animals were intermediate between their performances on the original training stimuli, resulting in typical generalization gradients. Closer examination of the data revealed that the median values were not representative of the behavior of the animals.     

Continuous opportunity for reinforcing brain stimulation

The performance of a rat provided with continuous opportunity to obtain reinforcing brain stimulation over a 20-day period is described in detail. The animal averaged 29.2 responses per min during the entire time. Testing session was terminated by experimenters, but a day-by-day analysis of behavior provided no evidence that the animal would have stopped responding.