Blocking acquisition of the rabbit's nictitating membrane response to serial conditioned stimuli

Three experiments demonstrated that prior training with one stimulus (CS1) would block acquisition of the rabbit's nictitating membrane response (NMR) to another stimulus (CS2) which was more contiguous to the US during serial compound training (CS1-CS2-US). Specifically, the CS1-US interval was 800 msec, which produces only a modest rate of CR acquisition, while the CS2-US interval was 400 msec, which is an optimal value for the NMR preparation. Experiment 1 demonstrated blocking when CS1 overlapped CS2, and Experiment 3 demonstrated blocking when CS1 and CS2 were presented in a strictly sequential fashion. Experiment 2 showed that the magnitude of blocking in the serial compound was comparable to that obtained in a simultaneous compound in which both the CS1-US and CS2-US intervals were 800 msec, thus making CS2 less contiguous with the US than in the serial compound. Moreover, the level of responding to CS2 in all serial compound groups (blocking and control) was lower than in the simultaneous compound groups. The present findings provide further evidence that the associative consequences of CS-US contiguity can be highly attenuated by processes of attention or competition for associative strength.     

Contrast and undermatching as a function of reinforcer duration and quality during multiple schedules

Eight pigeons pecked keys under multiple variable-interval two-minute variable-interval two-minute schedules. In Experiment 1, the reinforcers were 2, 4, or 8 seconds access to a food magazine. In Experiments 2 and 3, the reinforcers were grains that had been determined to be most-, moderately-, or non-preferred. Both positive and negative behavioral contrast occurred when the reinforcers in one component were held constant and the duration or type of reinforcer obtained in the other component varied. Undermatching occurred when the relative rate of responding during a component was plotted as a function of the relative duration of the reinforcers in that component.     

Stimulus control of delayed matching in pigeons: Directed forgetting

Pigeons were trained in delayed matching-to-sample with two postsample stimuli. A postsample R-cue signaled that a matching choice phase would follow. A postsample F-cue signaled that a matching choice phase would not follow. Previous research found reduced matching accuracy on F-cued probe trials when comparison stimuli were presented in the choice phase. The present four experiments systematically varied the events following an F-cue to determine the conditions under which the F-cue reduces delayed-matching accuracy. When F-cues and R-cues controlled different behavior, matching on probe trials was poor. When both cues controlled the same behavior, matching on probe trials was good. This result is best explained by the theory that comparison stimuli retrieve the sample representation, but only in the behavioral context established by the R-cue. The present research supports the view that response-produced stimuli serve a contextual role in animal short-term memory.     

RESEARCH SETTINGS IN INDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY: FACTS,FALLACIES, AND THE FUTURE1,2,3

Data were collected about research issues involving laboratory and field settings through a content analysis of the 1966, 1970, and 1974 volumes of the Journal of Applied Psychology, Organizational Behavior and Human Performance, and Personnel Psychology. Four general categories of data were collected: (a) affiliation of investigators, (b) topic areas investigated, (c) settings of the research, and (d) research strategies employed. Four common beliefs of either laboratory or field advocates were contradicted by the data. First, laboratory research was found fairly frequently in the industrial-organizational literature. Second, theory and hypothesis testing were not overemphasized. Third, laboratory research was as applied as field research. Lastly, studies published by researchers with nonacademic affiliations were as likely to have been conducted in laboratory settings as field settings. Recommendations were made to use the laboratory more frequently for theory and hypothesis based research and to use a variety of research strategies in both laboratory and field settings.     

Modeling medical diagnosis: Logical and computer approaches

Conclusion In the present article I have surveyed several approaches to modeling the clinical diagnostic process. I have argued that at this point of the field's development, logics which simulate the reasoning patterns and knowledge base of expert clinicians represent research programs that are most likely to succeed. No logic of diagnosis has yet attained the status of being definitive; in spite of striking progress much more research and testing is required. On the basis of various existing logics, I have attempted to articulate a number of desiderata which an ideal diagnostic logic should satisfy. In spite of these criticisms, I would maintain that programs such as MYCIN and INTERNIST have already matured to the point where they are useful both in consultations and in teaching diagnostic reasoning.Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, PA 15260. The author wishes to acknowledge gratefully the assistance of Drs. Jack D. Myers, Harry E. Pople, Jr., Joshua Nagin, and Randy Miller with the research that resulted in this essay and thanks to L. J. Cohen, J. F. Fries, R. N. Giere, and C. Whitbeck for comments on an earlier draft. Supported in part by training grant MB 00199-01 from the Bureau of Health Manpower (DHEW) and by the National Science Foundation and the National Endowment for the Humanities.Presented at a symposium on Philosophy and Medicine held at the American Philosophical Association's Eastern Division Meeting in Washington, D.C., December 27–29, 1978. This essay partially overlaps with an article on Problems in computer diagnosis to appear inThe Ethics of Diagnosis, H. T. Engelhardt, Jr. and S. Spicker (eds.) Dordrecht: D. Reidel, forthcoming.     

Sensitivity to grammatical structure in so-called agrammatic aphasics

Comprehension failures in agrammatic aphasics, as well as their difficulties in sentence construction, have been attributed to an underlying deficit involving the retrieval of syntactic structure. In this study we show that four agrammatic patients display a remarkable sensitivity to structural information, as indicated by their performance on a grammaticality judgment task. These results indicate significant sparing of syntactic knowledge in agrammatism, and suggest that the sentence comprehension disturbances in these patients do not reflect loss of the capacity to recover syntactic structure. In particular, accounts of the comprehension deficit in agrammatism that implicate a failure to exploit information carried by the closed class (function word) vocabulary are called seriously into question. Alternative explanations of the comprehension problem in agrammatism are explored.     

The role of attentional resources in automatic detection

The question of whether an automatic detection task requires the use of limited-capacity resources was investigated in a series of dual-task experiments. The automatic task required subjects to detect a consistently mapped target digit in a display of letters. This task was paired with a variety of concurrent visual discriminations that could either occur in close proximity to the automatic target or in a disparate display area. The main finding was that accuracy in each task was higher in conditions allowing attention to be shared than when it had to be divided between separate areas. These results indicate that detection of automatic targets depends on the allocation of spatial attention to the target's area.     

The Eureka—A Tool for Career Counseling

This article discusses the use of the Eureka for those seeking employment during the current economic trends affecting the labor market. Clients using this approach will be exposed to a wider variety of occupational options, thus expanding their range of realistic choices. The Eureka offers direction and current reliable information about the labor market in a short period of time.