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.     

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.     

Utility of the trauma symptom inventory's atypical response scale in detecting malingered post-traumatic stress disorder

The authors examined the Trauma Symptom Inventory's (TSI) ability to discriminate 88 student post-traumatic stress disorder (PTSD) simulators screened for genuine PTSD from 48 clinical PTSD-diagnosed outpatients. Results demonstrated between-group differences on several TSI clinical scales and the Atypical Response (ATR) validity scale. Discriminant function analysis using ATR revealed 75% correct patient classification but only 48% correct simulator classification, with an overall correct classification rate of 59% (positive predictive power [PPP] = .71; negative predictive power [NPP] = .51). Individual ATR cutoff scores did not yield impressive classification results, with the optimal cutoff (T score = 61) correctly classifying only 61% of simulators and patients (PPP = .66, NPP = .54). Although ATR was not developed as a malingered PTSD screen, instead serving as a general validity screen, caution is recommended in its current clinical use for detecting malingered PTSD.