In a conditional discrimination, 6 college students arranged six Cyrillic letters into groups of three based upon which of two additional Cyrillic letters (contextual stimuli) was present. All subjects demonstrated symmetry and transitivity within each class of equivalent stimuli. In a second conditional discrimination, two more Cyrillic letters were related to each contextual stimulus. Testing of symmetrical and transitive relations between the original contextual stimulus and the two new ones confirmed the development of two three-member classes of contextual stimuli. Subsequent tests demonstrated that the new contextual stimuli controlled the previously trained sample-comparison relations for all subjects.

In Experiment 1, four developmentally delayed adolescents were taught an A-B matchingto-sample task with nonidentical stimuli: given Sample Al, select Comparison Bl; given A2, select B2. During nonreinforced test trials, appropriate matching occurred when B stimuli appeared as samples and A stimuli as comparisons, i.e., the sample and comparison functions were symmetrical (B-A matching). During A-B or B-A matching test trials in which familiar samples and correct comparisons were presented along with novel comparisons, the subjects selected the correct comparisons. In tests with familiar samples and both incorrect and novel comparisons, subjects selected the novel comparisons, demonstrating control by both positive ("matching") and negative ("nonmatching") stimulus relations in A-B and B-A arrays. In Experiment 2, 12 developmentally delayed subjects were taught a two-stage arbitrary-matching task (e.g., A-B, C-B matching). Test sessions showed sample-comparison symmetry (e.g., B-A, B-C matching) and derived sample-comparison relations (e.g., A-C, C-A matching) for 11 subjects. These subjects also demonstrated control by positive and negative stimulus relations in the derived relations.

The influence of Skinner's Verbal Behavior on the generation of verbal behavior research was examined in a citation analysis that counted the citations of the book from January 1957 to August 1983 and described the fields in which the citations occurred. In a subsequent content analysis, citations were classified as directly influenced by the book if they selected at least one of Skinner's classes of verbal behavior for empirical examination. Directly influenced citations were sorted as descriptive, applied, or basic. The total number of citations of the book (836), the increasing annual number of citations, and the range of fields in which the book has been cited are evidence of its broad influence. However, empirical investigations employing at least one of Skinner's classes of verbal behavior are only a small proportion (31/836) of the citations. Of this small proportion an even smaller number constitutes experimental analyses (19/836). The small proportion of empirical studies suggests that Verbal Behavior is primarily cited for reasons other than as source material for research hypotheses in the study of verbal behavior. Some speculations are offered to account for the book's limited influence on research.

Six subjects, comprising one class at a school for the deaf, were given reinforcement consisting of time free from school work for remaining seated in the classroom. As a result, the frequency of leaving their chairs was sharply reduced. A second procedure presented free-time not contingent on remaining seated. Little change was seen in the already lowered response rate. An extension of the time required to be seated with corresponding reduction in the number of daily free-time periods did not reduce the effectiveness of the procedure. A one-day observation after six weeks indicated that the procedure was still effective. A one-day contingency reversal, requiring subjects to leave their chairs at least once during each seated period in order to receive free-time, substantially raised the frequency of out-of-seat responses.

Litter is an especially large and costly problem in unsupervised high-use recreational areas. This study investigated procedures to induce visitors to remove litter from an unsupervised U.S. Forest Service area in which signs attached to two litter stations instructed people to pick up and deposit litter. A small sum of money or chances on a larger sum given for participation usually resulted in more bags of litter being picked up per week. Although only a small proportion of the area's users participated in the project, ground surveys indicated the areas sampled were somewhat freer of litter during the payment condition. The results suggest that small monetary rewards may be a promising approach to litter control in unsupervised as well as supervised areas.

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A kindergarten class of five hearing-impaired children initiated and reciprocated sharing responses through the use of positive practice. Positive practice was conducted by a teacher in the regular classroom during a free-play period in which toys were available. Students who were not sharing practiced asking other students to share, and the rquested student was required to acquiesce in the sharing. Failure to acquiesce led to the positive practice of that correct role. A design which utilized individual probes interspersed among treatment sessions was employed. Positive practice resulted in more than a threefold increase in physical sharing of toys. All five children increased their physical sharing. Verbal sharing was unaffected by the procedure. Fifteen weeks after termination of the experiment, physical sharing still occurred approximately three times more often than during the initial baseline. Sharing generalized to a new teacher, a larger class with untrained students, and new toys. The results suggest that a teacher can systematically facilitate physical sharing among young children in the classroom by the use of positive practice.