Suppositions, extensionality, and conditionals: a critique of the mental model theory of Johnson-Laird And Byrne (2002)

P. N. Johnson-Laird and R. M. J. Byrne proposed an influential theory of conditionals in which mental models represent logical possibilities and inferences are drawn from the extensions of possibilities that are used to represent conditionals. In this article, the authors argue that the extensional semantics underlying this theory is equivalent to that of the material, truth-functional conditional, at least for what they term "basic" conditionals, concerning arbitrary problem content. On the basis of both logical argument and psychological evidence, the authors propose that this approach is fundamentally mistaken and that conditionals must be viewed within a suppositional theory based on what philosophical logicians call the Ramsey test. The Johnson-Laird and Byrne theory is critically examined with respect to its account of basic conditionals, nonbasic conditionals, and counterfactuals.     

Testing comprehension abilities in users of British Sign Language following CVA

Recent imaging (e.g., MacSweeney et al., 2002) and lesion (Hickok, Love-Geffen, & Klima, 2002) studies suggest that sign language comprehension depends primarily on left hemisphere structures. However, this may not be true of all aspects of comprehension. For example, there is evidence that the processing of topographic space in sign may be vulnerable to right hemisphere damage (e.g., Hickok, Say, Bellugi, & Klima, 1996), and the influence of iconicity on comprehension has yet to be explored. In this study, comprehension testing was conducted with 15 signers with unilateral brain damage, and with elderly Deaf controls. Four tests were administered: a test of iconic and non-iconic noun comprehension, a test of verb and sentence comprehension, a test of locative sentence comprehension, and a test of classifier comprehension. All tests were administered in British Sign Language (BSL), a language that has only recently been explored with lesioned signers (see Atkinson, Marshall, Thacker, & Woll, 2004; Marshall, Atkinson, Thacker, Woll, & Smulevitch, 2004; Marshall, Atkinson, Woll, & Thacker, in press). People with left hemisphere damage were impaired relative to controls on all tests. Those with right hemisphere damage performed well in the first two tests, but were impaired on locative sentences and classifiers. Neither group showed any effect of iconicity. The results shed further light on the laterality of sign language comprehension.     

Hypnotic disgust makes moral judgments more severe

Highly hypnotizable participants were given a posthypnotic suggestion to feel a flash of disgust whenever they read an arbitrary word. They were then asked to rate moral transgressions described in vignettes that either did or did not include the disgust-inducing word. Two studies show that moral judgments can be made more severe by the presence of a flash of disgust. These findings suggest that moral judgments may be grounded in affectively laden moral intuitions.     

Neuroleptic malignant syndrome: diagnostic and therapeutic dilemmas

Neuroleptic malignant syndrome (NMS) is a life threatening medical state complicating the use of antipsychotic medications and other drugs that affect the dopaminergic system on administration or withdrawal. The condition was recognised nearly half a century ago, shortly after the discovery of antipsychotic medications. However, there are still no systematic studies about NMS. There are no definitive guidelines on its treatment. Although early recognition is emphasised and usually possible, delayed diagnosis is not rare. We here report on a case of NMS complicated by renal failure, and possibly respiratory failure. The report underscores the seriousness of delayed diagnosis and puts forward a comprehensive management recommendation based on our experience and the existing literature.     

The wane of childhood amnesia for autobiographical and public event memories

We modified Bruce, Dolan, and Phillips-Grant's (2000) threshold procedure for determining the wane of childhood amnesia. In two experiments, undergraduates labelled childhood events (e.g., your first permanent tooth came in) as know or recollect memories and estimated their age at the event's occurrence. In both studies the estimated transition from mostly know memories to mostly recollect memories was roughly 4.7 years. This transition estimate was replicated in a sample of adults (ages 24-65 years) with both Bruce et al.'s event-generation task and the Experiment 1a questionnaire. By contrast, in two experiments a transition estimate of roughly 6 years was found for undergraduates' memories of public events (e.g., the Challenger explosion). The wane of childhood amnesia appears to occur around 4.7 years.     

How bad is a 10% chance of losing a toe? Judgments of probabilistic conditions by doctors and laypeople

We presented a Web questionnaire to 139 physicians and medical researchers and 109 laypeople. The subjects made judgments of badness and importance of prevention for eight medical conditions at each of seven different probability levels. By assuming that the response to each of the 56 risks was monotonically related to transformations of the probability and of the disutility of the condition, we could assess the relative effect of probability and disutility on each subject's judgments. Physicians' judgments were more sensitive than laypeople's judgments to changes in probability. Older and female laypeople were less sensitive to probability (and correspondingly, more responsive to differences in severity among medical conditions). Laypeople varied more than physicians in their responsiveness to probability. These results point to general individual differences in the effect of probability on evaluations of medical risks. They may also provide insight into causes and noncauses of physician-patient miscommunication.     

Schizophrenia and deliberate self-harm: a systematic review of risk factors

Deliberate self-harm (DSH) is a strong predictor of suicide in schizophrenia. The aim of this review was to identify risk factors for DSH in schizophrenia. This systematic review of the international literature examined cohort and case-control studies of patients with schizophrenia or related diagnoses that reported DSH as an outcome. Studies were identified by searching electronic databases and reference lists, and by consulting international experts. Fourteen studies met the eligibility criteria. Of the 29 variables examined by two or more studies, five (past or recent suicidal ideation, previous DSH, past depressive episode, drug abuse or dependence, and higher mean number of psychiatric admissions) were associated with an increased risk of DSH, and one (unemployment) was associated with a reduced risk. Schizophrenic patients with these risk factors need careful follow-up and monitoring, with treatment of any associated comorbid depression or drug abuse. Large, prospective studies of DSH in schizophrenia are needed to further define risk factors and to build on the findings of this review.     

Emotional intensity of idiographic sad memories in depression predicts symptom levels 1 year later

When cued with generic happy and sad words, depressed individuals have been found to articulate contextually impoverished memories of autobiographical events. Although this pattern predicts a worse symptomatic course of disorder in some depressed samples, longitudinal findings with the cue-word paradigm are inconsistent. To address the etiological significance of autobiographical memories outside the cue-word paradigm, the authors used an idiographic interview in which depressed participants generated memories of their happiest and saddest lifetime events. Each memory was coded for detail and emotional intensity. At a 1-year follow-up, participants' levels of depressive symptoms were reassessed. Lower emotional intensity of saddest memories predicted higher levels of depressive symptoms at follow-up. Several implications for understanding sadness and emotional disclosure in depression are discussed.     

Are there interactions among dysfunctional beliefs in obsessive compulsive disorder?

Contemporary cognitive models of obsessive-compulsive disorder emphasize the importance of various types of dysfunctional beliefs, such as beliefs about inflated responsibility, perfectionism and the importance of controlling one's thoughts. These beliefs have been conceptualized as main effects, each influencing obsessive-compulsive symptoms independent of the contributions of other beliefs. It is not known whether beliefs interact with one another in their influence on obsessive-compulsive symptoms. To investigate this issue, data from 248 obsessive-compulsive disorder patients were analyzed. Dependent variables were the factor scores on the 4 Padua Inventory subscales. Predictor variables were the factor scores from the 3 factors (inflated responsibility, perfectionism and controlling one's thoughts) of the Obsessive Beliefs Questionnaire and their 2- and 3-way interactions. Regression analyses revealed significant main effects; in almost all analyses one or more of inflated responsibility, perfectionism, and controlling one's thoughts factors predicted scores on the Padua factors even after controlling for general distress. There was no evidence that beliefs interact in their effects on obsessive-compulsive symptoms, thereby providing a relatively unusual instance in which a simpler explanation (main effects only) is just as powerful as a more complex model.     

Validity of test score interpretations for three self-concept measures based on differing theoretical models

Three theoretical models have been proposed to represent self-concept: (a) unidimensional; (b) multidimensional; (c) multidimensional hierarchical. Inventories have been developed under each of the three competing theoretical models; which model best represents self-concept is unclear. Typically, self-concept construct validation has utilized various approaches including correlational, multitrait-multimethod, and factor analytic methods. Another method, however, for assessing validity would be to determine the consequences of score interpretations using different measures specific to each of the theoretical models. This paper examined Messick's notion (1989) of the validity of test-score interpretations as applied to three of the most widely used measures derived under each of the three different theoretical models of self-concept. Results suggest that overall multidimensional measures are more consistent in classifying individual's self-concept than unidimensional measures.