Factors affecting the measurement of classically conditioned fear in rats following exposure to escapable versus inescapable signaled shock.

Three experiments are reported in which rats first received 50 escapable or inescapable signaled-shock trials. Experiment 1 (n = 22) employed an acquired-drive paradigm and found inescapable shock subjects learned a hurdle-jump response to escape the signal less rapidly than did escapable-shock subjects. Experiment 2 (n = 24) employed a conditioned emotional response paradigm and found inescapable-shock subjects suppressed more when the signal was introduced in the appetitive bar-pressing task. Both experiments measured spontaneous activity immediately following conditioning and found no group differences. Experiment 3 (n = 39) employed the same activity task and found no difference between escapable- and inescapable-shock groups when the signal was introduced into the activity task. Both groups displayed less activity than a nonshock control group during the signal. The results suggest that lack of control over the shock in the conditioning phase did not result in an increase of conditioned fear. The results are discussed in terms of a learned active-inactive predisposition to respond.     

Fixed-ratio and fixed-interval schedule control of matching-to-sample errors by children

Nine children, ages 4 through 7 yr, matched-to-sample on fixed-ratio, fixed-interval, variable-ratio, and variable-interval schedules of reinforcement. Simultaneous, zero-delay, and 2-sec delay matching were employed. Distributions of errors, in which the greatest number of errors occurred at the ordinal position immediately after reinforcement with fewer errors occurring at subsequent positions in the ratio, were produced by six of six children on fixed-ratio schedules for zero-delay and both of two children for 2-sec delay matching. Only two children of seven produced similar error distributions on simultaneous matching for fixed-ratio reinforcement. Variable-ratio schedules produced slightly lower accuracy for most subjects and no systematic error patterns for any subject. Error distributions occurred for all of the five children who experienced fixed-interval schedules for zero-delay matching. Peak error production occurred in the second fourth of the interval. Similar patterns were not produced on variable-interval schedules of equal reinforcement density. Schedule control of complex discriminated operants in children resembles control over similar responses of nonhuman animals.     

Evaluation of a home-based language training programme with severely mentally handicapped children

A home-based Language Training Programme was carried out with pre-school and school-age severely mentally handicapped children, over a 16–18-month period. Compared to control groups, the experimental groups did not show significantly greater progress on normreferenced measures of language development, although all groups showed significant improvement over time. The implications of these findings are discussed in the light of a number of methodological problems with the study.     

Control of adolescents' arbitrary matching-to-sample by positive and negative stimulus relations.

In Experiment 1, four developmentally delayed adolescents were taught an A-B matching-to-sample task with nonidentical stimuli: given Sample A1, select Comparison B1; 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.     

Cross-cultural social science research and questions of scientific medical imperialism

Concern for the rights and safety of individuals has caused clinical researchers to develop informed consent protocols for research involving human subjects. The applicapability of these regulations to social science research is often tenuous, since such research usually focuses on populations rather than individuals, and potential damage is apt to be political rather than personal. In cross-cultural social research, the protocols developed by Western clinical researchers may be not only ludicrously inapplicable, but intrusive and disruptive within the cultural context, raising questions of the intellectual imperialism of Western research ethics.     

Positive procedures and generalized self-choking

In two studies, self-choking by a middle-aged man with mental retardation was controlled both directly and indirectly by positive procedures. In the first study, paced eating procedures were employed to control postmealtime rumination. The frequency of generalized self-choking increased from periods where meals were paced to periods in which meals were not paced and vice versa. In the second study, redirection of self-choking and reinforcement for responses other than self-choking (DRO) reduced the frequency of self-choking, with the procedures applied successively to a number of different environments, trainers, distances from the client, and DRO parameters. These procedures related to a substantial reduction in generalized self-choking measured in other environments at other times.