Thinking around the corner: the development of planning abilities

The ability to plan and search ahead is essential for problem solving in most situations in everyday life. To investigate the development of planning and related processes, a sample of four- and five-year-old children was examined in a variant of the Tower of London, a frequently used neuropsychological assessment tool of planning abilities. The applied problems either required searching ahead for optimal solution or were solvable by pure step-by-step forward processing. Furthermore, the ambiguity of subgoal ordering was varied.Results revealed an age-related effect of search depth: the four-year olds’ planning accuracy was particularly decreased in problems demanding search ahead, while five-year olds mastered both problem types equally well. Interestingly, this interaction between age and search depth could not be accounted for by measures of working memory and inhibition. Differential effects of age were also found for subgoal ordering with respect to initial planning and movement execution times. In sum, planning abilities showed considerable development during late kindergarten age that appeared to be specifically associated with the integration and back-validation of the anticipated consequences of internally modeled actions. The present study demonstrates that a careful consideration of problem structure may greatly enhance the insights gained from the application of a routinely used assessment tool, the Tower of London. This may be especially advantageous when addressing specific subpopulations such as children or clinical samples.     

Microinfusion of the D1 receptor antagonist, SCH23390 into the IL but not the BLA impairs consolidation of extinction of auditory fear conditioning

In auditory fear conditioning, repeated presentation of the tone in the absence of the shock leads to extinction of the acquired fear response. Both the medial prefrontal cortex (mPFC) and the basolateral amygdala (BLA) are involved in extinction. Here we examined this involvement by antagonizing D1 receptors in both regions, in the rat. We microinfused the D1 receptor antagonist, SCH23390, into the infra-limbic part of the mPFC (IL) or BLA at different time points. SCH23390 mircoinfused into the IL either before extinction acquisition or following short extinction training resulted in impairment of extinction consolidation. Microinfusion of SCH23390 into the BLA, prior to acquisition of extinction caused impairment in acquisition of extinction without affecting extinction consolidation. This is supported by the results showing that microinfusion of SCH23390 into the BLA following a short-training session did not affect consolidation. These results further strengthen the role of mPFC in consolidation of extinction while highlighting the role of the D1 receptors in this process.     

The curious incident of the photo that was accused of being false: issues of domain specificity in development, autism, and brain imaging

We resume an exchange of ideas with Uta Frith that started before the turn of the century. The curious incident responsible for this exchange was the finding that children with autism fail tests of false belief, while they pass Zaitchik's (1990) photograph task (Leekam & Perner, 1991). This finding led to the conclusion that children with autism have a domain-specific impairment in Theory of Mind (mental representations), because the photograph task and the false-belief task are structurally equivalent except for the nonmental character of photographs. In this paper we argue that the false-belief task and the false-photograph task are not structurally equivalent and are not empirically associated. Instead a truly structurally equivalent task is the false-sign task. Performance on this task is strongly associated with the false-belief task. A version of this task, the misleading-signal task, also poses severe problems for children with autism (Bowler, Briskman, Gurvidi, & Fornells-Ambrojo, 2005). These new findings therefore challenge the earlier interpretation of a domain-specific difficulty in inferring mental states and suggest that children with autism also have difficulty understanding misleading nonmental objects. Brain imaging data using false-belief, "false"-photo, and false-sign scenarios provide further supporting evidence for our conclusions.     

The relationship between DSM-IV cluster B personality disorders and psychopathy according to Hare's criteria: clarification and resolution of previous contradictions

This study examines the relationship between DSM-cluster B personality disorders (PDs) and psychopaths according to Hare's criteria as detected by the Psychopathy Checklist (PCL:SV) in 299 violent offenders. To clarify some contradictions among several previous studies on this issue, individual cluster B PDs were looked at alone, excluding any cases of comorbidity with other PDs of this cluster. We found highly significant relationships between antisocial and borderline PD and Factor II of the PCL and a highly significant correlation between narcissistic PD and Factor I of the PCL. These results were to be expected from the theoretical basis of the development of the PCL and provide a contribution to the construct validity of the PCL, which until now has not been validated on such a large sample in Germany.     

Skills Practice in Dialectical Behavior Therapy for Suicidal Women Meeting Criteria for Borderline Personality Disorder

Dialectical Behavior Therapy (DBT) is an evidence-based practice for borderline personality disorder (BPD) and suicidal behavior that has been replicated with a variety of populations. Patients’ practice of behavioral skills taught in the group skills training component of DBT may be partly responsible for the positive treatment outcomes according to the skills deficit model of BPD that underlies DBT. This study was designed to examine the type and frequency of skills practiced by DBT patients. Participants were 49 women, who met criteria for BPD and current and chronic suicidal behavior, receiving 1 year of standard DBT as part of a clinical trial. Skills were recorded on the daily diary cards completed by participants each week and reviewed by their individual therapists. Results indicated that the majority of participants reported practicing skills most days throughout treatment. Crisis survival and mindfulness skills were practiced most frequently in our sample. Hierarchical linear modeling demonstrated that skills practice increased as a function of time in therapy. Directions for future research are discussed.     

DEWEX: A system for designing and conducting Web-based experiments

DEWEX is a server-based environment for developing Web-based experiments. It provides many features for creating and running complex experimental designs on a local server. It is freeware and allows for both using default features, for which only text input is necessary, and easy configurations that can be set up by the experimenter. The tool also provides log files on the local server that can be interpreted and analyzed very easily. As an illustration of how DEWEX can be used, a recent study is presented that demonstrates the system’s most important features. This study investigated learning from multiple hypertext sources and shows the influences of task, source of information, and hypertext presentation format on the construction of mental representations of a hypertext about a historical event.     

A time–cost optimization of the national postal distribution network

The postal distribution network in the Czech Republic consists actually of 69 local transit centres (according to the administrative division of the Czech Republic). Each of them operates the post offices in the given region. Some of the important local transit centres can be selected as sorting centres—transhipment points for postal consignments. The aim of this paper is to present a bicriterial optimization model for the selection of the subset of transhipment points from the set of transit centres and choosing their appropriate equipment, such as sorting machines. Another important output of the model is the assignment of the transit centres to the sorting centres. There are two basic optimization criteria defined in this model: minimization of the sum of investment and operational costs connected with building and operating of the sorting centres and the maximization of the percentage of postal consignments delivered to the appropriate post office in the desired time (next day). The proposed model contains several thousands of zero‐one variables and constraints. The model has been verified, and the results accepted. Copyright © 1999 John Wiley & Sons, Ltd.