Dennis C. Cogan

Effects of laughter and relaxation on discomfort thresholds.

Two experiments were conducted to test the proposal that laughter is a pain antagonist. In Experiment I, thresholds for pressure-induced discomfort of 20 male and 20 female subjects were measured after each subject listened to a 20-min-long laughter-inducing, relaxation-inducing, or dull-narrative audio tape or no tape. Discomfort thresholds were higher for subjects in the laughter- and the relaxation-inducing conditions. In Experiment II, 40 female subjects were matched for pressure-induced discomfort thresholds. Their discomfort thresholds were measured after they listened to a laughter-inducing, interesting narrative, or uninteresting narrative audio tape, completed a multiplication task, or experienced no intervention. Discomfort thresholds increased for subjects in the laughter-inducing condition. Laughter, and not simply distraction, reduces discomfort sensitivity, suggesting that laughter has potential as an intervention strategy for the reduction of clinical discomfort.

Response patterning in hippocampectomized rats

Abstract Partially hippocampectomized, cortical, and normal control rats were given single alternation of reinforcement and nonreinforcement training in Experiment 1. Contrary to earlier findings, all three groups demonstrated significant pattern running. No significant extinction differences were observed. In Experiment 2, partially hippocampectomized, cortical, and normal control rats were given single alternation of immediate and delayed reinforcement training. Results essentially similar to those in Experiment 1 were obtained. The results of the two experiments indicated that partially hippocampectomized rats can acquire an inhibition in response to patterns of reinforcement. The implications of these findings for the attention model of hippocampal function and the memory model of the partial reinforcement effect are discussed.

Chronic Pain and Self‐efficacy: The Effects of Age, Sex, and Chronicity

Abstract: Higher self‐efficacy (SE) is associated with lower pain ratings in chronic pain patients, although longer experience with chronic pain leads to lower SE scores. Self‐efficacy in pain patients does not appear to be clearly related to sex or age, however. This study investigated the effects of gender, age, length of pain experience (chronicity) on SE and pain ratings.

Passive avoidance learning in hippocampectomized rats under different shock and intertrial interval conditions

Abstract Two experiments were run comparing the performance of normal, cortically damaged and hippocampally damaged rats on a passive avoidance task [37]. The results of Experiment 1 indicated that hippocampally damaged rats learn to passively avoid after no more than three consecutive punishment trials. In Experiment 2, the passive avoidance performance of groups of normal, cortically damaged, or hippocampally damaged rats was studied using a factorial combination of two intertrial intervals (60 sec and 60 min) and two shock intensities (1.8 mA and 1.8 mA). Results indicated that the greatest and most persistent deficits in the performance of hippocampally ablated animals occurred in the low shock, short intertrial interval condition. No differences between the performance of hippocampally damaged animals and control animals were found in the high shock, long intertrial interval condition. Performance of the hippocampectomized animals in the remaining groups was poorer than controls, but intermediate between the performance of the hippocampal animals in the aforementioned groups. Results were interpreted as supporting an information processing model of hippocampal function.

Social facilitation effects on runway and maze behavior in mice

Runway and maze acquisition and extinction performance of solitary, mirror-coaction, and audience groups of male albino mice were compared in an attempt to test Zajonc’s theory of social facilitation. In each situation, one of the conspecific groups performed in a manner similar to the solitary group. The audience and solitary groups ran more slowly than the mirror group in the maze, and the mirror and solitary groups ran faster than the audience group in the runway. These findings failed to support predictions made from Zajonc’s theory. Apparently nonallelomimetic mammalian species do not respond to social facilitation in the same way that nonallelomimetic insects (cockroaches) do.

Learned helplessness: Now you see it, now you don’t

Eleven active avoidance tests of “leamed helplessness” were run on rats to determine the feasibility of using the paradigm as an analog of depression. In two experiments, the avoidance task required a barpress response. In the remaining experiments, a one- or two-way shuttle response was required. Numbers of trials, shock level, shock time, and several other aspects were varied. In seven cases, the “helpless” animals took marginally longer to learn. In four cases, the reverse was true. The differences between groups did not reach statistical significance in any of the 11 experiments. The authors concluded that “learned helplessness,” in rats, is too sensitive to minor procedural changes to constitute a good paradigm for the study of depression.

Selected schedules of reinforcement in the black-tailed prairie dog (Cynomys ludovicianus)

Wild black-tailed prairie dogs were run on FR, FI, VR, and VI schedules for Noyes pellet reinforcement. Cumulative barpress responses, postreinforcement pause lengths, and responses per second were recorded. The highest response rates occurred in the VR schedules, with the lowest response rates coming in the FI schedules. Fixed-ratio schedules had the longest postreinforcement pauses, VI schedules had the shortest. At the upper levels of the fixed-ratio schedules (FR 90–100), the animals ceased to respond consistently. Generally, data from prairie dogs were consistent with data reported in studies from other mammalian species.

EFFECTS OF N-LENGTH ORDER ON RESISTANCE TO EXTINCTION IN THE RAT

Two experiments are reported which suggest that the regular sequencing of N-lengths both within and between daily acquisition sessions may function as a significant determiner of the strength of resistance to extinction. Rats were trained with increasing, decreasing, or random N-length sequences either within daily blocks of trials (Exp. I) or across days (Exp. II). In both experiments increasing N-lengths, e.g., R-N-R-NN-R-NNN-R, produced greater resistance to extinction than decreasing N-lengths, e.g., R-NNN-R-NN-R-N-R. The results were interpreted as more in accord with the frustration position of Amsel rather than the sequential-memory view of Capaldi.

Discrimination in Parakeets ( Melopsittacus Undulatus ). As a Function of Age

Eight parakeets (Melopsittacus undulatus), four from 1 to 2 months old and four from 9 to 12 months old, were taught to discriminate between a circle and a triangle in a Y-maze using a non-correction procedure. Although no age differences were found, all the birds met the stringent criterion for learning of 15 consecutive correct responses. It was concluded that the parakeet would make an interesting subject for further study.

Introduction of Novel Irrelevant Cues in Discrimination Learning

20 albino rats were trained to criterion (90% correct) on a brightness discrimination in the presence of irrelevant form cues. Using an optional shift paradigm, all Ss were required to reverse the initially learned response with respect to brightness cues. During this phase, novel form cues were introduced for one group (10 Ss). Split-plot factorial analyses of variance (trials and errors to criterion) indicated there were reliable differences in learning rate between the novel-cue and same-cue groups in the optional shift phase. No significant consistent responses were observed in the test phase. Results were interpreted as more in support of continuity theory, although the lack of information on the conditions under which inter-task transfer fails to occur makes this conclusion somewhat tenuous.