Model inference or model selection: discussion of Klugkist, Laudy, and Hoijtink (2005)

I. Klugkist, O. Laudy, and H. Hoijtink (2005) presented a Bayesian approach to analysis of variance models with inequality constraints. Constraints may play 2 distinct roles in data analysis. They may represent prior information that allows more precise inferences regarding parameter values, or they may describe a theory to be judged against the data. In the latter case, the authors emphasized the use of Bayes factors and posterior model probabilities to select the best theory. One difficulty is that interpretation of the posterior model probabilities depends on which other theories are included in the comparison. The posterior distribution of the parameters under an unconstrained model allows one to quantify the support provided by the data for inequality constraints without requiring the model selection framework.     

Assessing the executive function deficits of patients with Parkinson's disease: utility of the Tower of London-Drexel

The aim of the study was to investigate the utility of the Tower of London-Drexel (TOLDX) in assessing the executive deficits associated with Parkinson's disease (PD). We sought to determine whether the TOLDX would differentiate between (a) patients with PD and healthy control participants (HCP), (b) demented and nondemented patients, and (c) depressed and nondepressed patients. A new TOLDX score, stimulus bound, was introduced to assess utilization behaviors. Furthermore, the convergent and divergent validity of the TOLDX was examined. The TOLDX total move, rule and time violation, and stimulus-bound scores of patients with PD significantly differed from the HCP. Demented and nondemented patients also differed significantly in their TOLDX performance, with the stimulus-bound score being the most significantly differentiating score. However, the depressed and nondepressed patients did not differ in their TOLDX performance. Support was found for the convergent and divergent validity of the TOLDX. The clinical and theoretical implications of the findings are discussed.     

The emerging dialogue between psychoanalysis and neuroscience: neuroimaging perspectives

Current progress in the cognitive neurosciences is highly relevant to the development of psychoanalytic theory and practice. Neuroscience is today becoming mature enough to provide empirical biological approaches for the investigation of psychoanalytic models and observations. The current state of functional neuroimaging techniques is reviewed, selected paradigms and findings relevant to psychotherapy research are presented, and ways to pursue the dialogue between psychoanalysts and neuroscientists are discussed, as are some related obstacles and pitfalls. The emerging dialogue between psychoanalysts and neuroscientists may help not only to reestablish a solid position of psychodynamic theory and treatment in contemporary medicine, but also to bridge the division between "psychological" and "somatic" treatments, and gain important insights into the mind-brain relationship.     

Default Probability

A probability may be called “default” if it is neither derived from preestablished probabilities nor based on considerations of frequency or symmetry. Default probabilities presumably arise through reasoning based on causality and similarity. This article advances a model of default probability based on a featural approach to similarity. The accuracy of the model is assessed by comparing its predictions to the probabilities provided by undergraduates asked to reason about mammals.     

Improving performance and increasing the use of non-positive testing in a rule-discovery task

A well-documented characteristic of rule discovery behaviour is subjects' infrequent use of negative testing. Previous attempts at increasing the use of negative testing have met with little success. In an evaluation task, we found that subjects appreciate the benefits of negative testing and disconfirmation (Kareev & Halberstadt, this issue). Further, when given the choice, subjects prefer to begin their inquiry by employing a reception mode of inquiry, and only later switch to a generative strategy (Halberstadt & Kareev, 1992). In the present study we had subjects solve two rule-discovery problems. For the training problem, 180 subjects were assigned either to the traditional generation mode, in which subjects had to generate number triplets, or to a reception mode, in which subjects were presented with number triplets by the experimenter. For the subsequent test problem both groups used the traditional generation mode. Results revealed that subjects trained by the reception mode were more likely to use non-positive tests and more likely to solve the second problem. Apparently, training under the less demanding reception mode enabled subjects to realize the potential relevance of nonpositive testing.     

Evaluating negative tests and refutations in a rule discovery task

Subjects participating in Wason's rule discovery task (1960) overwhelmingly try to confirm rather than refute their currently held hypothesis. Such a strategy is often inadequate and runs counter to the canons of scientific methodology. The present study was designed to investigate subjects' differential evaluation of test strategies and outcome. One-hundred and sixty students participated in two experiments in which they had to judge someone else's potential test items in Wason's task. Experiment 1 demonstrated that exposure to various histories has a mediating effect on the strength of the confirmation bias. In Experiment 2, subjects knew the researcher's rule and thus whether each proposed test item would lead to confirmation or refutation of the hypothesis under consideration. The preferred items were those that alerted the subject to an incorrect hypothesis (refutation) and those that turned out to be positive instances of the rule sought after, with the combination of the two (a negative test leading to refutation) being most highly evaluated.     

Witnessing across time: accessing the present from the past and the past from the present

We are used to the idea that trauma in the past interrupts our capacity to grasp the present. But present or recent trauma can have a similar dissociative effect on our capacity to experience the more distant past. Contemporary trauma can rob the past of its goodness, leaving one feeling as if the past is gone, dead, separated from the present. The vitalization of the present by the past or the past by the present requires that experiences be linked across time. These links are created, in both directions, via categories of experience characterized by shared affect (Modell 1990, 2006). Such categories are created, in turn, by metaphor; and the construction of these metaphors across time requires that one be able to occupy self-states in both the past and the present that can then bear witness to one another. Trauma can result in the dissociation of these self-states from one another, leading to a disconnection of present and past.