A comparison of the effects of formal similarity among trigrams and among word triads

The central question of this report concerned the role of formal similarity in free recall of lists of trigrams and lists of three-letter word triads. Similarity was manipulated among trigrams by duplicating letters and among triads by duplicating words. An initial study showed that lists of 16 letters were learned more rapidly than a list of 16 three-letter words. Therefore, in the major experiment, the Ss were given all appropriate elements on test trials so that only associative learning was required. Increases in formal similarity caused decreases in rate of learning for both types of lists, and the mechanisms of the interference seemed to be the same for both types of lists, However, the learning of the trigram lists was more rapid than the learning of the triad lists, the difference being maximal with low similarity.     

Effects of conditioned reinforcement frequency in an intermittent free-feeding situation,

Key-pecking intermittently produced a set of brief exteroceptive stimulus changes under two-component multiple schedules of conditioned reinforcement. Throughout the study, free access to grain was concurrently provided on an intermittent basis via a variable-interval tape. Free food presentations scheduled by the tape were delivered if no peck had been emitted for 6 sec, and the brief stimulus changes produced by responding under the multiple schedules were those which accompanied food presentation. The second component of each multiple schedule was always associated with a 1-min, variable-interval schedule of conditioned reinforcement. The schedule associated with the first component was systematically varied and conditioned reinforcement was either absent (extinction) or programmed on a 1-, 3-, 6-, or 12-min variable-interval schedule. Under these conditions, rate of responding in the manipulated component decreased monotonically with a decrease in the frequency of conditioned reinforcement. In addition, contrast effects were often obtained in the constant, second component. These results are similar to those obtained with similar multiple schedules of primary reinforcement.     

Second-order avoidance behavior in monkeys

Two monkeys were trained on a three-component multiple schedule using discrete trials. In one component (food), a response terminated a red stimulus and produced food and S(Delta). In the second component (avoidance), a response terminated a green stimulus and avoided shock. In the third component (optional), a response terminated a blue stimulus and produced S(Delta). The consequence of not responding in the blue stimulus, however, was the production of either a food or an avoidance trial. Manipulation of these consequences showed that when food trials were available only a small percent of the time after optional trials, the subjects tended not to respond in the blue, even though this led to an increase in the total number of avoidance trials per day. If only avoidance trials followed as a consequence of not responding in the optional component, the animals terminated the blue stimulus and avoided the avoidance trials. Throughout the experiment both subjects maintained consistently low shock rates (about 10 per day) and these were not affected by the various manipulations. The data suggest that a stimulus associated with avoidance can be a conditioned aversive stimulus and will maintain a more remote avoidance response under certain conditions.     

Blockages in therapy

Compiled and edited from lectures on psychoanalytic technique given by the late Karen Horney at the American Institute for Psychoanalysis during the years 1946, 1950, 1951 and 1952. Further lectures in this series will appear in subsequent issues of the Journal.     

A recognition test of vocabulary using signal-detection measures,and some correlates of word and nonword recognition

In the first of three experiments, university undergraduates were presented a list of 300 words and 100 nonwords in two sessions. Their confidence that an item was a word was indicated for each item on a 6-point scale. This experiment demonstrated the feasibility of creating a recognition test of vocabulary. In Expeiment II, 100 items were chosen to form a subtest, and the subtest was cross-validated on a new sample of subjects. The tests in Experiments I and II were scored using signal-detection measures. The primary criterion, SAT (verbal) scores, correlated approximately .60 with the test scores. In Experiment III subjects scaled the words and nonwords for four psychological attributes. These were submitted to a stepwise regression with the confidence ratings from Experiment I as the dependent variable. It was concluded that associability. frequency, orthography, and pronounceability all may be components of word recognition. However, only frequency was found to be a significant predictor of the confidence of recognition of nonwords.     

MEASURING CLIENT GAINS FROM STAFF-IMPLEMENTED PROGRAMS

Confidence in the adequacy with which staff implement training programs requires an analysis of the impact on the client. In two experiments, measures were devised to reflect this impact. In the first, a measure of the consistency with which clients participated in a toilet-training program revealed their participation to be erratic. Consistent participation occurred after a public display of the consistency of participation was introduced. In Experiment II, detailed measures were devised to reflect the client's performance during the implementation of two physical-therapy programs: range-of-motion and ambulation. Additionally, standardized measures of the benefits that accrued from their participation in these programs were devised. Improvements in both measures were slight and unstable during a condition of immediate feedback (supervisor praise) to staff but substantial improvements were obtained with the addition of a public display of the client's performance.     

The role of comprehension in children's observational learning of a syntactic rule

This experiment tested the hypothesis that there is a relationship between children's comprehension of a syntactic form and the effectiveness of modeling in promoting imitation of that form. Nursery and kindergarten children received pretests for both comprehension and production of reversible passive sentences. Children who produced no passive sentences were classified either as high, intermediate, or low comprehenders on the basis of their comprehension test performance. Within each of these three groups, children were randomly assigned either to a modeling or to a no-modeling control condition. Children in the treatment condition heard a model use passive sentences to describe a series of pictures. As predicted, the imitation post-test scores of these children were significantly related to their comprehension pretest scores. No significant relationship between the post-test scores and the comprehension scores of control subjects was detected. Children exposed to the model in all three comprehension groups received significantly higher post-test scores than did their respective counterparts in the no-modeling condition. These results are discussed in terms of the hypothesis that language learning proceeds from comprehension to imitation to production.     

Statistical significance levels of nonparametric tests biased by heterogeneous variances of treatment groups

The statistical significance levels of the Wilcoxon-Mann-Whitney test and the Kruskal-Wallis test are substantially biased by heterogeneous variances of treatment groups--even when sample sizes are equal. Under these conditions, the Type I error probabilities of the nonparametric tests, performed at the .01, .05, and .10 significance levels, increase by as much as 40%-50% in many cases and sometimes as much as 300%. The bias increases systematically as the ratio of standard deviations of treatment groups increases and remains fairly constant for various sample sizes. There is no indication that Type I error probabilities approach the significance level asymptotically as sample size increases.