Conspiracy theories on the basis of the evidence

Synthese - Conspiracy theories are often portrayed as unwarranted beliefs, typically supported by suspicious kinds of evidence. Yet contemporary work in Philosophy argues provisional belief in...     

Aphasics' sensitivity to contextual appropriateness conditions for pragmatic indicators

Twenty normal and twenty aphasic subjects were tested for their understanding of implicit meanings of the French adverbs même (even), aussi (also), and surtout (mainly). Their sensitivity to the contextual appropriateness conditions of such items was analyzed in a multiple-choice paradigm requiring them to select from three figures the one which was best described by a sentence like "Show me the figure that is même (aussi, surtout) red." A global quantitative comparison indicates that aphasics' performance was inferior to that of the normal controls. Yet, the analysis of individual responses allowed the identification of three different subgroups of aphasics: the first produced responses identical to the normals' responses; the second seemed to ignore the adverb and systematically selected the figure with the highest amount of the asserted color; and the third produced responses identical to the normals' responses for surtout but had difficulties with même or aussi. As concerns the relationship between aphasics' performance and their scores on literal language comprehension tests, the data favor the dissociation between literal and pragmatic factors in comprehension. Finally, no clear relationship was observed between aphasia type and aphasics' performance, although three points are noted in the discussion: (1) all the conduction aphasics performed like normals, (2) among the Broca's aphasics, the one with the clearest agrammatic verbal output produced responses similar to those of the normals, and (3) there was no anomic patient in the second subgroup.     

Factors associated with Borderline pathology in school-age children

The Diagnostic Interview for Borderlines as revised (DIB-R) for use with children and chart review was completed using the records of 54 children, ages 6 to 12 years, who had been admitted to a public psychiatric hospital. Based on the results of the DIB-R, the children were grouped as borderline and nonborderline. The two groups were then compared with regard to 52 independent variables which have historically been associated with the borderline diagnosis. Stepwise logistic regression was used to identify the cluster of diagnostic and independent variables which best discriminated the borderline subjects. Self-destructive behavior, irritable affect, anhedonia, and an externalizing disorder diagnosis at the time of admission accounted for 95.4% of the borderline children. These findings are in contrast to previous studies which have found an assortment of neuropsychological and/or neurological deficits and stressed the importance of a tendency toward psychotic regression on psychological testing as discriminative variables. The authors underscore the idea that borderline pathology may represent a spectrum of disorders and the need for a more specific psychiatric nosology in describing and diagnosing these children.     

Reception of Morse code through motional, vibrotactile, and auditory stimulation

The potential for communication through the kinesthetic aspect of the tactual sense was examined in a series of experiments employing Morse code signals. Experienced and inexperienced Morse code operators were trained to identify Morse code signals that were delivered as sequences of motional stimulation through up-down displacements (roughly 10 mm) of the fingertip. Performance on this task was compared with that obtained for both vibrotactile and acoustic presentation of Morse code using a 200-Hz tone delivered either to the fingertip through a minishaker or diotically to the two ears under headphones. For all three modalities, the ability to receive Morse code was examined as a function of presentation rate for tasks including identification of single letters, random three-letter sequences, common words, and sentences. Equivalent word-rate measures (i.e., product of percent correct scores and stimulus presentation rate) were nearly twice as high for auditory presentation as for vibrotactile stimulation, which in turn was about 1.3 times that for motional stimulation. The experienced subjects outperformed the inexperienced subjects by amounts that increased with task complexity. For example, the former were able to receive sentences at 18 words/min with motional stimulation, whereas the latter, following 75 h of training, were unable to perform this task. The present results and those of other research with tactual communication systems are compared, particularly regarding estimates of information-transfer rates.     

Perceived social context and risk preference: A re-examination of framing effects in a life-death decision problem

This study examines the effects of perceived group context on subjects risk attitudes and their sensitivity to the framing of choice outcomes in a ‘life-death’ decision problem. It seeks to uncover the psychological mechanisms underlying decision-making biases by systematically manipulating the decision context in which the ‘life-death’ problem was described. The study revealed that subjects risk preferences varied as a function of the experimental manipulations. Previously observed reversals in preferences (framing effects) appeared in large-group contexts and disappeared in small-group and family contexts. When considering the fate of small groups, subjects unambiguously favored the probabilistic outcome, no matter how the ‘life-death’ decision problem was framed. The empirical data obtained from the present study suggest that human choice patterns are behaviorally distinguishable across large-group, small-group, and family social contexts.     

Is Default Logic a Reinvention of Inductive-Statistical Reasoning?

Currently there is hardly any connection between philosophy of science and Artificial Intelligence research. We argue that both fields can benefit from each other. As an example of this mutual benefit we discuss the relation between Inductive-Statistical Reasoning and Default Logic. One of the main topics in AI research is the study of common-sense reasoning with incomplete information. Default logic is especially developed to formalise this type of reasoning. We show that there is a striking resemblance between inductive-statistical reasoning and default logic. A central theme in the logical positivist study of inductive-statistical reasoning such as Hempels Criterion of Maximal Specificity turns out to be equally important in default logic. We also discuss to what extent the relevance of the results of Logical Positivism to AI research could contribute to a reevaluation of Logical Positivism in general.     

Self-focused attention and reactions to conflicting standards

A fundamental postulate of self-awareness theory that has received considerable empirical support is that self-focused attention increases behavioral consistency with “standards of correctness.” This appears to be true whether the standards are internal (such as attitudes or values) or external (e.g., norms). There is some question, however, as to what happens in situations in which an important personal standard conflicts with a salient external standard. Research by E. Diener and T. K. Srull (Journal of Personality and Social Psychology, 1979, 37, 413–423) has suggested that under such circumstances the social standard is likely to predominate. However, there is reason to believe that the standards employed in their study may not have been very salient nor very important to the subjects. In the present experiment, subjects with either conservative or liberal sexual attitudes were exposed to information suggesting a prevailing norm of sexual liberalism. They were then asked to respond to a number of sexual and nonsexual attitude measures while their attention was or was not self-directed by means of a mirror. Primary results indicated that self-awareness enhanced conformity to the social standard (as in Diener & Srull, 1979) for the conservative subjects; however, correlational analyses within the self-focused and non-self-focused conditions indicated that self-aware subjects did not “abandon” their personal standards when responding to the conformity pressure. Instead, their responses tended to be more in line with their previously expressed attitudes than did the responses of the non-self-focused group. Results are discussed in terms of the effects of self-awareness on reactions to potent, but conflicting behavioral standards.     

Language function and dysfunction among Chinese- and English-speaking polyglots: Cortical stimulation, Wada Testing, and clinical studies

Language functions in a group of Chinese- and English-speaking polyglots living in a multiracial society have been investigated by several methods: the effects of cortical stimulation on object-naming and reading tasks in patients who required awake craniotomy, lateralization of cerebral dominance for speech by the Wada Test, and the pattern of language loss and recovery following stroke. The data indicate that these polyglots were all left hemisphere dominant for the languages tested: no consistent evidence for increased participation by the right hemisphere for language functions was found. The cortical stimulation experiments provided data most compatible with the "differential localization" model of cerebral localization in bilingualism. The variable which most influenced performance in all of these investigations was which language was used primarily for speaking as well as reading and writing at the time of the study.     

Effects of response-dependent and independent electric shock on schedule-induced polydipsia

In Experiment I, lever pressing by rats was maintained by the delivery of food pellets under a 45-sec fixed-interval schedule. Fixed-time 180-sec and fixed-interval 180-sec schedules of shock delivery were systematically superimposed on the baseline food schedule to study effects on schedule-induced water intake. Response-dependent shock had little, if any, effect on water intake, whereas shocks independent of lever pressing attenuated fluid intake. In Experiment 2, rats received food pellets under a fixed-time 60-sec schedule. Electric shock delivered concurrently under a variable-time 180-sec schedule, but never while the animal was licking or within 5 sec after licking terminated, led to similar attenuation of water intake. These findings suggest that schedule-induced polydipsia is sensitive to differences in the functional properties of response-independent and dependent electric shock.