The role of locomotion in the acquisition and transfer of spatial knowledge in children

The role of locomotion in the acquisition and transfer of spatial knowledge was investigated in 144 five-, seven- and eleven-year-old children. Two experiments were conducted in the Kiel locomotor maze. In the first experiment, one group of children explored the spatial layout by walking through the maze, while another learned the maze by surveying the layout. In the second experiment, children were exposed to one of two orientation tests in the maze, one of which could be solved using "landmark orientation", the other only using a "relational place orientation". Children sitting by the side of the experimental chamber surveying the maze needed fewer trials to learn the spatial layout than children exploring the environment in the locomotion condition, but in the orientation test demanding the "relational place orientation" children who had explored the maze in the locomotion condition outperformed the children in the non-locomotion condition. Results are discussed in the context of cognitive mapping models.     

Bimanual interference associated with the selection of target locations

Four experiments were conducted to identify the locus of interference observed during the preparation of bimanual reaching movements. Target locations were specified by color, and the right-hand and left-hand targets could be either the same or a different color. Movements of different amplitudes (Experiment 1) or different directions (Experiment 2) to targets of the same color were initiated more quickly than symmetric movements to targets of different colors. These results indicate that costs observed during bimanual movements arise during target selection rather than during motor programming. Experiments 3 and 4 further examined the interference associated with target selection. Reaction time costs were found with unimanual movements when the target was presented among distractors associated with responses for the other hand. Interference observed during bimanual reaching appears to reflect difficulty in segregating the response rules assigned to each hand.     

Day treatment of patients with personality disorders: experiences from a Norwegian treatment research network

This study sought to investigate the following research questions: Are time-limited day treatment programs for patients with personality disorder (PD) effective outside resourceful university settings, and what are the overall treatment results when the program is implemented on a larger scale? Do all categories and subtypes of PDs respond favorably to such treatment? How intensive should such day treatment programs be? All patients (n = 1,244) were consecutively admitted to eight different treatment programs in the Norwegian Network of Psychotherapeutic Day Hospitals from 1993 to 2000. Altogether, 1,010 patients were diagnosed with PD. Avoidant, borderline, not otherwise specified (NOS), and paranoid PD were the most common conditions. SCID-II and MINI were used as diagnostic instruments. Outcome measures included GAF Global Assessment of Functioning, (GAF; American Psychiatric Association, 1994), SCL-90R, CIP, Quality of Life, work functioning and parasuicidal behavior, measured at admittance, discharge and 1-year follow up. The attrition rate was 24%. The number of dropouts did not improve over time. As a group, completers with PD improved significantly on all outcome variables from admittance to discharge and improvement was maintained or increased at follow up. Treatment results were best for borderline PD, cluster C patients, PD NOS and No PD, and poorer for cluster A patients. Units with a high treatment dosage did not experience better outcomes than those with a low treatment dosage (10 hours per week). Results from the University unit were not better than those from units at local hospitals or mental health centers.     

Grandiose-Manipulative,Callous-Unemotional,and Daring-Impulsive: the Prediction of Psychopathic Traits in Adolescence and their Outcomes in Adulthood

There has been much debate about how to measure psychopathic traits in adolescence. One of the main issues is whether one should focus on callous-unemotional (CU) traits alone, or CU traits in combination with Grandiose-Manipulative (GM) and Daring-Impulsive (DI) traits. The current study first investigates the extent to which youth who are high on CU traits are also high on GM and DI traits. In addition, the study investigates if being high on both CU and GM, and high on both CU and DI, identify groups that are particularly characterized by past and future impairments. To investigate this, data from the Cambridge Study in Delinquent Development (CSDD) was analyzed. The CSDD is a prospective longitudinal study of 411 English boys spanning over 50 years. The information available at age 12–14 was coded on the Antisocial Process Screening Device (APSD). Childhood risk factors were measured at age 8–10 and later life outcomes were measured at age 32. The results indicate that being high on CU in combination with DI delineates a clinically interesting group who are characterized by high childhood risk and poorer adult life outcomes. The same applied to the high CU/high GM group, but to a lesser extent.     

Genetic and environmental contributions to the co-occurrence of depressive personality disorder and DSM-IV personality disorders

One of the main controversies with regard to depressive personality disorder (DPD) concerns the co-occurrence with the established DSM-IV personality disorders (PDs). The main aim of this study was to examine to what extent DPD and the DSM-IV PDs share genetic and environmental risk factors, using multivariate twin modeling. The DSM-IV Structured Interview for Personality was applied to 2,794 young adult twins. Paranoid PD from Cluster A, borderline PD from Cluster B, and all three PDs from Cluster C were independently and significantly associated with DPD in multiple regression analysis. The genetic correlations between DPD and the other PDs were strong (.53-.83), while the environmental correlations were moderate (.36-.40). Close to 50% of the total variance in DPD was disorder specific. However, only 5% was due to disorder-specific genetic factors, indicating that a substantial part of the genetic vulnerability to DPD also increases the vulnerability to other PDs.     

Bicycle helmets – A case of risk compensation?

Several studies have shown that bicycle helmets have the potential of reducing injuries from accidents. Yet, no studies have found good evidence of an injury reducing effect in countries that have introduced bicycle helmet legislation. Two of the most promising explanations for why helmet laws do not work as intended are risk compensation and shifts in the cycle population as a response to the law.The present article investigates whether the lack of effect of helmet wearing laws is due to risk compensation mechanisms or population shifts (i.e. discouraging cyclists with the lowest accident risk, and thereby increasing the overall average risk per cyclist). A random sample of 1504 bicycle owners in Norway responded to a questionnaire on among other things helmet use, bicycle equipment use, accident involvement, cycling behaviour and risk perception. Data were analysed by using structural equation model (SEM). The results show that the cyclist population in Norway can be divided into two sub-populations: one speed-happy group that cycle fast and have lots of cycle equipment including helmets, and one traditional kind of cyclist without much equipment, cycling slowly. With all the limitations that have to be placed on a cross sectional study such as this, the results indicate that at least part of the reason why helmet laws do not appear to be beneficial is that they disproportionately discourage the safest cyclists.     

Associative memory or algorithmic search: a comparative study on learning strategies of bats and shrews

Two common strategies for successful foraging are learning to associate specific sensory cues with patches of prey ("associative learning") and using set decision-making rules to systematically scan for prey ("algorithmic search"). We investigated whether an animal's life history affects which of these two foraging strategies it is likely to use. Natterer's bats (Myotis nattereri) have slow life-history traits and we predicted they would be more likely to use associative learning. Common shrews (Sorex araneus) have fast life-history traits and we predicted that they would rely more heavily on routine-based search. Apart from their marked differences in life-history traits, these two mammals are similar in body size, brain weight, habitat, and diet. We assessed foraging strategy, associative learning ability, and retention time with a four-arm maze; one arm contained a food reward and was marked with four sensory stimuli. Bats and shrews differed significantly in their foraging strategies. Most bats learned to associate the sensory stimuli with the reward and remembered this association over time. Most shrews searched the maze using consistent decision-making rules, but did not learn or remember the association. We discuss these results in terms of life-history traits and other key differences between these species. Our results suggest a link between an animal's life-history strategy and its use of associative learning.