Decision-making impairments in patients with Parkinson's disease

A high percentage of Parkinson's disease (PD) patients show cognitive impairments in addition to the cardinal motor symptoms. These deficits primarily concern executive functions most probably linked to dysfunctions in prefrontal regions due to decreased dopaminergic transmission in fronto-striatal loops. To investigate possible associations between decision-making and executive functions in PD, we examined 20 non-demented PD patients and 20 healthy control subjects with a neuropsychological test battery and the Game of Dice Task. In this computerised decision-making task, the rules for gains and losses and the winning probabilities are obvious and stable. Thus, strategic components besides feedback processing might influence decision-making in this task. We found that PD patients were impaired in the Game of Dice task performance and that the frequency of disadvantageous choices correlated with both executive functions and feedback processing. We suggest that decision-making deficits of PD patients in explicit gambling situations might be associated with dysfunctions in two different fronto-striatal loops: the limbic-orbitofrontal-striatal loop, involved in feedback processing, and the dorsolateral prefrontal-striatal loop, involved in executive functions.     

Crews: A Distinct Type of Work Team

Distinctions among different types of work teams have been emerging in the theoretical literature as a key to understanding important work team processes. This has been precipitated by an increased appreciation of the importance of a work team's operating environment on such processes. Moreover, such distinctions are felt to be useful to practice in such areas as team staffing, training, and establishing leadership requirements. The present study investigates the concept of crews and contrasts it with other types of work teams by empirically assessing crewness, the extent to which a work team can be classified as a crew. A new scale of crewness was developed and administered to various collectives of workers including fire fighter crew members and project team members in order to establish the unique qualities of crews to show that they are a distinct type of work team. Construct and discriminant validity evidence is offered in support of the crewness scale. Approaches for further investigation of this distinction are also provided in order to guide both research and practice in this area.     

Influence of consonantal context on the pronunciation of vowels: a comparison of human readers and computational models

In two experiments, we found that college students' pronunciations of vowels in nonwords are influenced both by preceding and following consonants. The predominance of rimes in previous studies of reading does not appear to arise because readers are unable to pick up associations that cross the onset-rime boundary, but rather because English has relatively few such associations. Comparisons between people's vowel pronunciations and those produced by various computational models of reading showed that no model provided a good account of human performance on nonwords for which the vowel shows contextual conditioning. Possible directions for improved models are suggested.     

The nature of speech production impairments in anterior aphasics: an acoustic analysis of voicing in fricative consonants

This study investigated the acoustic characteristics of voicing in English fricative consonants produced by anterior aphasics and the effects of phonetic context on these characteristics. Three patients produced voiced and voiceless fricative-vowel syllables in isolation, following a voiced velar stop, and following a voiceless velar stop. Acoustic analyses were conducted of the amplitude and patterning of glottal excitation, as well as fricative noise duration. Results showed that, although the patients are able to coordinate the articulatory gestures for voicing in fricative consonants, they demonstrated abnormal patterns of glottal excitation in the amplitude measures, owing to weaker amplitudes of glottal excitation in voiced fricatives. Context effects failed to emerge because of dysfluent speech. These results suggest that the locus of the speech production deficit of anterior aphasics is not at the higher stages of phoneme selection or planning but rather in articulatory implementation, one related to laryngeal control.     

Stability and change in longitudinal water-level task performance.

Three longitudinal samples of children (N = 481), 8 to 16 years old, were assessed 3 times at yearly intervals on 8 water-level items. The within-child change in task performance over age is viewed as a stochastic process of the child changing or remaining in 1 of 3 latent (strategy) states: (a) bottom-parallel responders, (b) random responders, or (c) accurate responders. A random-effects binomial mixture distribution is used to model performance at each age. Change over age is gauged by a stochastic transition model. Although there was improvement in task performance over age, the more general finding is that strategy stability, not change, is most typical.     

Self-reflection and the temporal focus of the wandering mind

Current accounts suggest that self-referential thought serves a pivotal function in the human ability to simulate the future during mind-wandering. Using experience sampling, this hypothesis was tested in two studies that explored the extent to which self-reflection impacts both retrospection and prospection during mind-wandering. Study 1 demonstrated that a brief period of self-reflection yielded a prospective bias during mind-wandering such that participants’ engaged more frequently in spontaneous future than past thought. In Study 2, individual differences in the strength of self-referential thought — as indexed by the memorial advantage for self rather than other-encoded items — was shown to vary with future thinking during mind-wandering. Together these results confirm that self-reflection is a core component of future thinking during mind-wandering and provide novel evidence that a key function of the autobiographical memory system may be to mentally simulate events in the future.     

Neurocognitive Function and Suicide in U.S. Army Soldiers

This prospective cohort study used administrative data from the Army Study to Assess Risk and Resilience in Servicemembers to examine associations between neurocognitive functioning and subsequent suicidal events among Regular Army enlisted soldiers during the years 2004–2009. Cases were all soldiers who completed the Army's Automated Neuropsychological Assessment Metrics (ANAM) computerized testing battery prior to documented suicide attempt (n = 607), ideation (n = 955), or death (n = 57). Controls were an equal‐probability sample of 9,893 person‐months from other soldiers. Exploratory factor analysis of five ANAM tests identified a general neurocognitive factor that excluded the mathematic processing test (MTH). When examined separately in logistic regression analyses that controlled for sociodemographics and prior mental health diagnosis, both the general neurocognitive factor (logit [β] = ?.197 to ?.521; p < .01) and MTH (β = ?.024 to ?.064; p < .05) were associated with all outcomes. When both predictors were examined simultaneously, the general neurocognitive factor continued to be associated with all outcomes (β = ?.164 to ?.417; p < .05) and MTH continued to be associated with suicide attempt (β = ?.015; p = .046) and ideation (β = ?.014; p = .018). These small but robust associations suggest that future research must continue to examine the extent to which objective neurocognitive tests may enhance understanding and prediction of suicide risk.     

The deviant citizen: Measuring potential positive relations between counterproductive work behaviour and organizational citizenship behaviour

Studies have shown a strong negative correlation between counterproductive work behaviour (CWB) and organizational citizenship behaviour (OCB), and opposite correlations with hypothesized antecedents. Such observed correlations may have been erroneously caused by three measurement artefacts: items measuring absence of CWBs, rather than behaviours that exceed requirements or expectations in OCB scales; supervisory halo; and agreement rather than frequency response format. A new OCB scale, the OCB‐checklist (OCB‐C) was used that did not have these artefacts. Contrary to prior expectations from the literature, positive relations were found between CWB and OCB, and stressors and OCB. Theoretical explanations for positive CWB/OCB relations (demand‐elicited OCB, social loafing, work process problems, rater perceptions and attributions, and aggravated job stress processes) are discussed.     

Team Mental Models,Team Goal Orientations,and Information Elaboration,Predicting Team Creative Performance

This study aimed to enhance understanding of team creativity by investigating the type of team mental models that team members develop during their work on a creative problem solving task. We hypothesized that teams that develop dissimilar team mental models, compared to similar and complementary team mental models, will achieve a higher information elaboration. This effect will be moderated by the development of a high learning-performance team goal orientation. Information elaboration in turn was hypothesized to predict team creative performance. In a 3 (similar/dissimilar/complementary team mental models) × 3 (learning/performance/learning-performance goal orientation) experimental study on a sample of 33 teams (N = 98) we found that teams that developed more dissimilar team mental models and experienced a learning-performance goal orientation intervention engaged in more information elaboration. Information elaboration, in turn, mediated the relationship between the interaction between team mental models and team goal orientations and team creative performance. Implications for research on team mental models and team creativity are discussed.