DIMENSIONS COGNITIVES ET COMPORTEMENTALES CHEZ LES JOUEURS RÉGULIERS ET OCCASIONNELS AU BLACKJACK

Empirical studies in the psychology of gambling have revealed at least two well supported findings: (1) irrational cognitions outnumber rational cognitions during gambling (Gaboury and Ladouceur, 1987; Ladouceur, Gaboury, Dumont and Rochette 1988); (2) risk-taking behavior increases as a function to exposure to gambling activities (Ladouceur, Mayrand and Tourigny 1987; Ladouceur, Tourigny and Mayrand 1986). The present study compared regular and occasional gamblers on cognitive and behavioral measures during a blackjack session using the thinking aloud method. The results confirmed that regular players emitted more irrational thoughts than occasional gamblers. The theoretical and practical implications of those results are discussed within the general context of the psychology of gambling.     

Theory change in immunology part II: The clonal selection theory

This two-part article examines the competition between the clonal selection theory and the instructive theory of the immune response from 1957–1967. In Part I the concept of a temporally extended theory is introduced, which requires attention to the hitherto largely ignored issue of theory individuation. Factors which influence the acceptability of such an extended theory at different temporal points are also embedded in a Bayesian framework, which is shown to provide a rational account of belief change in science. In Part II these factors, as elaborated in the Bayesian framework, are applied to the case of the success of the clonal selection theory and the failure of the instructive theory.     

Prismatic displacement of vision induces transient changes in the timing of eye-hand coordination

Eye-hand coordination was investigated during a task of finger pointing toward visual targets viewed through wedge prisms. Hand and eye latencies and movement times were identical during the control condition and at the end of prism exposure. A temporal reorganization of eye and hand movements was observed during the course of adaptation. During the earlier stage of prism exposure, the time gap between the end of the eye saccade and the onset of hand movement was increased from a control time of 23 to 68 msec. This suggests that a time-consuming process occurred during the early prism-exposure period. The evolution of this time gap was correlated with the evolution of pointing errors during the early stage of prism exposure, in such a way that both measures increased at the onset of prism exposure and decreased almost back to control values within about 10 trials. However, spatial error was not entirely corrected, even late in prism exposure when the temporal organization of eye and hand had returned to baseline. These data suggest that two different adaptive mechanisms were at work: a rather short-term mechanism, involved in normal coordination of spatially aligned eye and hand systems, and a long-term mechanism, responsible for remapping spatially misaligned systems. The former mechanism can be strategically employed to quickly optimize accuracy in a situation involving misalignment, but completely adaptive behavior must await the slower-acting latter mechanism to achieve longterm spatial alignment.     

Comparison between Oral and Written Spelling in Alzheimer's Disease

Written and oral spelling were compared in 33 patients with Alzheimer's disease (AD) and 25 control subjects. AD patients had poorer spelling results which were influenced by orthographic difficulty and word frequency, but not by grammatical word class. Lexical spelling was also more deteriorated than phonological spelling. Moreover, oral spelling was more impaired than written spelling in AD patients, whereas no difference was present between oral and written spelling of controls. Analysis of spelling errors showed that, for controls, errors were predominantly phonologically accurate in both spelling tasks. Significantly, AD patients produced more phonologically accurate than inaccurate errors in written spelling, whereas these errors did not differ in oral spelling. In contrast to controls who produced more constant than variable responses in oral and written spelling, AD patients made more variable responses (words correctly spelled in one task but incorrectly in the other) and they showed many instances of variable errors (different misspellings from one spelling task to the other). Two stepwise regression procedures showed that written misspellings were specifically correlated with language impairment, whereas oral spelling errors were correlated with attentional and language disorders. These results suggest that AD increases the attentional demands of oral spelling process as compared to written spelling. This dissociation argues, either for a unique Graphemic Buffer in which oral spelling requires more attentional resources than written spelling or for the hypothesis of separate buffers for oral and written spelling.     

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.     

Selective delayed alternation deficits in dominantly inherited olivopontocerebellar atrophy

In order to characterize more completely the nature of the frontal lobe-type cognitive changes in patients with dominantly inherited olivopontocerebellar atrophy (OPCA) we administered two tasks sensitive to frontal system dysfunction, delayed alternation (DA) and delayed response (DR), to 12 patients from one OPCA family. Affected members from this family have previously been shown to have a marked and widespread cerebral (including frontal) cortical cholinergic reduction as severe as that observed in Alzheimer's disease. Performance on DA, but not on DR, was significantly impaired in the OPCA patients compared to that in the controls. We suggest that the DA deficits in OPCA could be a consequence of a loss of cholinergic innervation to orbitofrontal or possibly temporal cortical areas and/or damage to the integrity of the cerebello-frontal neuronal connections.     

Preimaginal induction of adult behaviour in insects

This review illustrates the role of preimaginal experiences in four main aspects of insect life: feeding, habitat choice, host selection, and social relationships. After an illustration of the two former aspects with examples taken from various species, special attention is paid to the two latter aspects. First, an experiment is described, which demonstrates the existence of preimaginal induction involved in host selection by the solitary parasitoid wasp Dinarmus basalis (Hymenoptera: Pteromalidae). Then, a review of preimaginal induction in ants' behaviour is presented; orientation of social behaviour, particularly altruism, is mainly determined by preimaginal imprinting. All the examples developed in this review clearly show that insects can no longer be considered as strictly, rigidly “pre-programmed” beings. Their complex behavioural development and plasticity is clearly documented.     

Processing of temporal duration information in working memory after frontodorsal tumour excisions

This study aimed to test the hypothesis that impairments of temporal duration processing after frontal lobe lesions reflect deficits in executive monitoring functions rather than a domain-specific deficit in the maintenance of duration information in working memory. Patients with frontodorsal lesions, clinical controls with post-central lesions, and healthy controls performed recognition and classification tasks, which should allow for testing maintenance and monitoring functions, respectively. Results showed mild non-selective impairments of the frontal patients on both temporal and spatial recognition tasks, but a marked selective degradation on temporal classification while performance on spatial classification was unimpaired. This suggests that maintenance of duration information in working memory after frontal lesions is basically preserved but that, depending on executive task characteristics, there is a specific deficit in the strategic organization of this type of information.