Making sense of sensitivity in the human operant literature

Human operant behavior is often said to be controlled by different variables or governed by different processes than nonhuman operant behavior. Support for this claim within the operant literature comes from data suggesting that human behavior is often insensitive to schedules of reinforcement to which nonhuman behavior has been sensitive. The data that evoke the use of the terms sensitivity and insensitivity, however, result from both between-species and within-subject comparisons. We argue that because sensitivity is synonymous with experimental control, conclusions about sensitivity are best demonstrated through within-subject comparisons. Further, we argue that even when sensitivity is assessed using within-subject comparisons of performance on different schedules of reinforcement, procedural differences between studies of different species may affect schedule performance in important ways. We extend this argument to age differences as well. We conclude that differences across populations are an occasion for more precise experimental analyses and that it is premature to conclude that human behavior is controlled by different processes than nonhuman behavior.     

Family demographics of clinically referred children: What we know and what we need to know

Published empirical studies were reviewed to establish family demographics of clinically referred children and adolescents. Data on parental marital status were collected from studies of referred and nonreferred children and adolescents in six empirical journals. Data on family socioeconomic status (SES) and child race or ethnicity were also collected. Based on 86 studies that presented parental marital status, 56.4% of clinically referred children and adolescents live with both their biological mother and biological father. Family SES data were difficult to summarize because of the different methods of presenting this information. When considering race and ethnicity, 86% of the children and adolescents in the clinical samples were Caucasian American. Of the studies that were originally reviewed, 80.4% did not include parental marital status and 36. 7% did not include SES, race, or ethnicity of the participants. There were no significant differences between journals in the rates of inclusion of family demographic data. In addition to revealing family demographic information about children and adolescents who participate in clinical research, these data highlight the lack of consistency in the presentation of family demographic data in published research. Suggestions are provided to help researchers colled and present meaningful family demographic data in clinical and nonclinical research with children and adolescents.This study was completed with support from the Division of Sponsored Research at the University of South Florida and preparation of this article was supported in part by National Institute of Mental Health Grant R29 49601-02 to the first author. We express our gratitude to Georgetta Bosco and Tracy Burbine for their diligent data collection in the library.     

Are women invisible as leaders?

This study shows that women are unlikely to be seen as leaders. Subjects (n=448) rated each member of a five-person group (shown in a photograph) on leadership attributes and also chose one of the five as “contributing most to the group.” Eight different stimulus slides were used. In two slides the “head-of-the-table” cue to group leadership was pitted against sex-role stereotypes. A man seated at the head of the table in a mixed-sex group was clearly seen as leader of his group, but a woman occupying the same position was ignored. The head-of-the-table cue identified women as leaders only in all-female stimulus groups. The data were consistent with the hypotheses that sex stereotypes still control social judgments, and that discrimination operates nonconsciously and in spite of good intentions.     

Free recall and complexity of pictorial stimuli

In order to explore variables underlying primacy and recency effects in free recall of pictorial material, norms were developed using 120 subjects who rated the vividness and complexity of slides. Two experiments were then run in which two levels of each of these variables (extreme high and low ratings) were factorially combined. In the first experiment 24 subjects were shown three mixed lists, two short and one long (consisting of materials of all four combinations of vividness and complexity), and in the second experiment 12 subjects were shown four pure lists (consisting of materials of a single type). Analysis of variance showed list length in the mixed list experiment and complexity in both experiments to be strong determinants of recall. Greatest recall was for items of low complexity in short lists. Weak, but statistically significant, serial position effects were evident, particularly for less complex items. The effects of primacy and recency seem to decrease with increasing complexity of visual materials, perhaps because of the greater difficulty in rehearsing more complex pictures either verbally or iconically.     

DESCRIPTIVE ANALYSIS OF EATING REGULATION IN OBESE AND NONOBESE CHILDREN

Bite rate, sip rate, and concurrent activities of six 7-yr-old children, three obese and three nonobese, were observed at lunchtime over a six-month period. A procedure for decreasing bite rate, putting eating utensils down between bites, was implemented in a multiple-baseline across-subjects design. Sip rates and concurrent activities were observed to assess behavioral covariations. In addition, bite rate and amount of food completed were computed over six food categories to analyze food preferences. Results indicated the control of bite rate across all subjects, with a significant reduction in amount of food consumed. Correlations between the response classes indicated they were at least partially independent. Differences in eating behavior of obese and nonobese subjects were observed for breadstuffs and milk drinking.     

Use of small group contingencies and special activity times to manage behavior in a first-grade classroom

Management procedures were succesfully employed to decrease the frequency with which first-grade children left small instructional centers. To decrease the out-of-center behavior, access to a 30-minute special activity time was made available to different groups as a function of everyone's remaining within his group instructional center. One occurrence of out-center behavior resulted in a cost of ten minutes of special activity time for the children in that center. The frequency of out-of-center behaviors quickly decreased from Baseline I to the Modification I condition, increased when the modification condition was removed, and decreased again in Modification II.Observations made on the percent of the children's appropriate social and academic behaviors showed increases during the modification conditions. Also, the time the teacher spent in responding to inappropriate behavior decreased and the time spent in instruction increased during the modification conditions.     

Habituation,memory, and the evaluative dimension of meaning

Two groups of subjects were exposed to a series of 20 either positively evaluated words (E⁺ group) or negatively evaluated words (E^? group). On the twenty-first trial, half the subjects in E⁺ group (the E^+? group) received a negatively evaluated word while the other half of the subjects received a further positively evaluated word (E⁺⁺ group). A similar subdivision was made with the E^? group to yield E^?+ and E^?? groups. Skin conductance responses to all stimulus words were measured. The responses of the E^+? and E^?+ groups were compared to those of their control groups (E⁺⁺ and E^??) for stimulus words 21 and 22. The results of these analyses, and the data concerning responses prior to stimulus word 21, indicated that subjects habituated to semantic stimuli of the same evaluative meaning. Memory for the words was assessed postexperimentally and its relationship to the orienting response in discussed.     

The role of reference in children's acquisition of a miniature artificial language

Nursery school children were presented with a simple miniature artificial language in one of three conditions. In the first, the stimuli to which the words referred contained an inherent lawful relationship and the language syntax reflected this relationship. In the second, the stimuli contained an inherent lawful relationship but the language syntax did not reflect this relationship. In the third, no lawful relationship existed among the stimuli to which the words referred so the language syntax imposed an arbitrary relationship among stimuli. Subjects in the first group were able to produce more correct utterances than those in the other two groups when the stimuli to which the words referred were not present, suggesting that some form of semantic mediation mechanism was being used. Evidence from novel constructions indicates that for both groups using stimuli containing an inherent lawful relation there were interactions between semantic learning mechanisms and syntax learning mechanisms.     

A comprehensive dining program for mentally retarded adults

Twenty-six types of behavior (e.g. uses fork in socially appropriate manner, chews food before swallowing) were treated in a course of independence training, using 80 institutionalized retarded adults (40 experimentals and 40 no-treatment controls). The 3-month long training phase incorporated a number of treatment components including in vivo modeling, peer social reinforcement, self-evaluation and monitoring; then a four-month follow-up. A group (i.e. experimentals and controls) by sex, by time, analysis of variance was computed with repeated measures on the last dimension (pre, post, follow-up measures = time). A significant difference was obtained between the experimentals and controls on post-test and follow-up     

Imagery and recognition memory: The effects of relational organization

Begg (1978), among others, has recently argued that recognition performance is independent of the size and number of units stored in memory, that is, the degree of interitem organization. In four experiments, interactive imagery was contrasted with separation imagery on recognition memory. In the first two studies, the recognition of single words was better under separation instructions; in the final studies, in which recognition of pairs of words was required, performance was better following interactive imagery. Rather than being independent of the size of memory units, recognition depends upon the relationship between the size of the units encoded at learning and the nature of the test items themselves.