Fixed-interval punishment of running in hamsters

Four hamsters received brief electric shocks contingent upon running in a wheel. The fixed interval between shocks was varied systematically from 0 to 60 sec. Time spent running was directly related to the length of the fixed interval, while running speed remained roughly constant. Running depended on the fixed interval between shocks in the same way as bar-pressing maintained by food reinforcement, despite the fact that running was not established with nor maintained by explicit reinforcement.     

Positive contrast following gradual and abrupt increases in reward magnitude using delay of reinforcement

In Experiment 1, rats were given a 1-pellet reward for 48 preshift trials. During a subsequent 20-trial postshift phase, one group was shifted to a 12-pellet reward on Trial 1, a second was shifted on Trial 11, and a third was given 1 more pellet each trial and then 12 pellets for the last 10 trials. The speeds of all three groups increased to a level above that of a control group given a 12-pellet food reward throughout training (positive contrast). In experiment 2, rats were shifted from 1 to 12 pellets either gradually or abruptly following either abbreviated training (9 trials) or extended training (20 trials). One group of control subjects received 12 pellets throughout training. The results revealed a positive contrast effect for gradually shifted subjects following extended training but not following abbreviated training. The abrupt shift procedure produced positive contrast following abbreviated training but only a marginal effect following extended training. These results indicate that, contingent upon the amount of preshift training, either gradual or abrupt reward increases may produce positive contrast.     

Effects of expectancies of different reward magnitudes in transfer from noncontingent pairings to instrumental performance

In two experiments, rats received noncontingent pairings of two stimuli with food reward, one paired with small reward and the other with large reward, and received bar press training with large reward or with small reward. When the noncontingent stimuli (NS) were presented for test during subsequent rewarded bar pressing and during early extinction of bar pressing, responding for each group was faster in the presence of the NS which was paired with the same reward magnitude that group received in bar press training than to the NS which had been paired with a different reward magnitude. As extinction progressed, all groups responded more slowly in the presence of the NS which had been paired with the large reward than in the presence of the NS which had been paired with small reward. These results were interpreted as indicating that responding in the presence of an NS depends on: (i) whether the reward expectancy elicited by the NS has been conditioned to the instrumental response, and (ii) the relationship between the reward expected in the presence of the NS and that received in test.     

Stimulus redundancy and immediate recall

This study examined immediate recall in two stimulus prefix and two stimulus suffix conditions and in a condition that combined a prefix and suffix. Suffixes and the combination of a prefix with a suffix interfered more with recall overall than did prefixes. Performance in each of the conditions that included a prefix was significantly better overall than in appropriate control conditions, in which interference was augmented by a redundant element in recall. It was suggested that prefixes and suffixes lie operationally on a continuum and that their effects result from the subject's inability to dissociate the redundant element from the memory series. However, the location of redundancy imposes different processing requirements that differentially influence recall.     

Wilhelm Dilthey: Forerunner of humanist social thought

Humanist social thought is as a meadow in the forest of positivist science. Much of this space was cleared by Wilhelm Dilthey, not only through his attack on the fundamental assumptions of positivism, but also through his formulation of a critical method by which the works of free human consciousness could be understood. The first tenet of positivism is that the world is made up of ‘out there’ objectively knowable ‘facts’. Dilthey undercut this notion by asserting that the subject matter of the human studies was not mere facts of nature, but rather objectified expressions of the human mind. The second central assumption of positivism is that these facts are explainable or determined by general causal laws. In contrast, Dilthey asserted that, while we can explain the natural world, human action must be understood through an interpretive rather than a causal logic. In demonstrating and specifically describing such an interpretive procedure, Dilthey provided an epistemological and methodological grounding fur a humanistic science of the person and of the social world. His ideas illuminate the works even of his critics and his influence, though largely unacknowledged, continues to be widespread in all the human studies.     

Sex and coding strategy effects on reaction time to hemispheric probes

Two experiments were conducted to investigate the influence of coding instructions on cerebral laterality differences. Experiment I required 20 subjects (10 female) to use either rehearsal or imagery coding strategies in a recognition task with word probes to the right and left hemispheres. No hemispheric differences were found, but sex of subject was found to be related to coding strategy. Ten subjects (5 female) in Experiment II performed a similar task, except picture probes were used. Subjects using rehearsal coding responded faster to left-hemisphere probes, but faster to right-hemisphere probes when imagery coding was employed. The differing laterality effects in these experiments were attributed to naming responses implicitly required in Experiment II.     

Recognition memory for deducible information

Recent research in language comprehension indicates a constructive encoding process in which the linguistic input is transformed into some more general semantic structure which is stored. In attempting to characterize the nature of such structures, some conflicting findings have been observed for paragraphs which describe similar set-theoretic relations, linear orderings and set inclusions. While the linear ordering research supports the constructivist theory, the set inclusion work does not. The set inclusion studies, however, employed true-false tests and not the usual recognition tests. The present study investigated the processing of set inclusion paragraphs in a self-paced study/recognition test paradigm. Results supported the constructivist theory and were contrary to predictions based upon the previous set inclusion research. Subjects were unable to differentiate between presented information and unpresented deducible information. These results were discussed in terms of accuracy constraints of different tasks on memorial performance and a possible interaction of Type of Test by Universal Quantification.