Enumeration of collective entities by 5-month-old infants

Recent findings suggest that infants are capable of distinguishing between different numbers of objects, and of performing simple arithmetical operations. But there is debate over whether these abilities result from capacities dedicated to numerical cognition, or whether infants succeed in such experiments through more general, non-numerical capacities, such as sensitivity to perceptual features or mechanisms of object tracking. We report here a study showing that 5-month-olds can determine the number of collective entities -- moving groups of items -- when non-numerical perceptual factors such as contour length, area, density, and others are strictly controlled. This suggests both that infants can represent number per se, and that their grasp of number is not limited to the domain of objects.     

Some markers of mirroring appear intact in schizophrenia: evidence from mu suppression

Although schizophrenia is associated with impairments in social cognition, the scope and neural correlates of these disturbances are largely unknown. In this study, we investigated whether schizophrenia patients show impaired functioning of the mirror neuron system (MNS), as indexed by electroencephalographic (EEG) mu (8–13 Hz) suppression, a hypothesized biomarker of MNS activity that is sensitive to the degree of social interaction depicted in visual stimuli. A total of 32 outpatients and 26 healthy controls completed an EEG paradigm that included six action observation or execution conditions that differed in their degrees of social interaction. Participants also completed a validated empathy questionnaire. Across both groups, we found a significant linear increase in mu suppression across the conditions involving greater levels of social engagement and interaction, but no significant group or interaction effects. Patients self-reported diminished empathic concern and perspective taking, which showed some moderate relations to mu suppression levels. Thus, the schizophrenia group showed generally intact modulation of MNS functioning at the electrophysiological level, despite self-reporting empathic disturbances. The disturbances commonly seen on self-report, performance, and neuroimaging measures of mentalizing in schizophrenia may largely reflect difficulties with higher-level inferential processes about others’ emotions, rather than a basic incapacity to share in these experiences.     

A psychometric study of the Drug Use Disorders Identification Test-Extended in a Norwegian sample

Motivation is a widely used concept in substance use treatment, and is commonly seen as a premise for change during treatment. Different measures of motivation have been suggested. A relatively new instrument is the Drug Use Disorders Identification Test-Extended (DUDIT-E), developed in Sweden. This instrument has recently been introduced in Norway. The present study examined the Motivational Index of the Norwegian version of the Drug Use Disorders Identification Test-Extended (DUDIT-E). We tested whether the three-factor model ("Positive aspects of substance abuse"; "Negative aspects of substance abuse"; and "Treatment readiness") suggested by previous studies could be replicated in a sample of Norwegian inpatients. Responses to the DUDIT-E were obtained from 105 patients admitted to inpatient substance abuse treatment in Northern Norway. Exploratory common factor analyses were used to compare the factor structure from the current sample with the Swedish sample of mainly detoxification patients and prison inmates. The current sample did not include prison inmates, and it consisted of more women than the Swedish sample. The samples did not differ according to age or substance dependency. The analyses suggested that six primary factors was the most efficient way of combining the item scores, and not 11 as in the Swedish sample. A second-order factor analysis found best support for a two-factor solution, and hence, did not replicate the previously suggested three-factor model either. Several regression analyses comparing the efficiency of the different ways of combining the DUDIT scores in primary or secondary factor scores indicated that the model involving six sum scores had best merit and should be explored further.     

Origins of "us" versus "them": prelinguistic infants prefer similar others

A central feature of human psychology is our pervasive tendency to divide the social world into "us" and "them". We prefer to associate with those who are similar to us over those who are different, preferentially allocate resources to similar others, and hold more positive beliefs about similar others. Here we investigate the developmental origins of these biases, asking if preference for similar others occurs prior to language and extensive exposure to cultural norms. We demonstrate that, like adults, prelinguistic infants prefer those who share even trivial similarities with themselves, and these preferences appear to reflect a cognitive comparison process ("like me"/"not like me"). However, unlike adults, infants do not appear to prefer others with an utterly arbitrary similarity to themselves. Together, these findings suggest that the phenomena of ingroup bias, and enhanced interpersonal attraction toward those who resemble ourselves, may be rooted in an inherent preference for similarity to self, which itself may be enhanced during development by the influence of cultural values.     

Mental planning and the Tower of London task

The Tower of London (TOL) task has been used extensively as a test of planning ability in neuropsychological patients and normal populations. Participants are asked to preplan mentally a sequence of moves to match a start set of discs to a goal, and then to execute the moves one by one. The mental preplanning stage has been identified as critical to efficient performance. The current experiments examined whether manipulations of mental preplanning influence performance on the TOL. In Experiment 1, the effect of different planning instructions was examined. Those told to make full mental plans spent considerably longer in planning than participants given no specific planning instructions, yet there was no effect of instruction condition on the efficiency of executing plans. Experiment 2 investigated whether people were able to plan mentally, by looking at their ability to identify intermediate states of an optimum mental plan. Results indicated that most individuals could make accurate preplans up to two subgoals ahead, but not three. However, making an efficient preplan did not result in better subsequent execution of moves to solve the TOL trial. It is concluded that people can make effective mental plans for a limited number of moves. However, on the TOL task, mental preplanning does not offer benefits in terms of quicker performance, or more accurate solution. The nature of planning in the TOL task is therefore questioned.     

Medically Documented Suicide Ideation Among U.S. Army Soldiers

We used administrative data to examine predictors of medically documented suicide ideation (SI) among Regular Army soldiers from 2006 through 2009 (N = 10,466 ideators, 124,959 control person‐months). Enlisted ideators (97.8% of all cases) were more likely than controls to be female, younger, older when entering service, less educated, never or previously deployed, and have a recent mental health diagnosis. Officer ideators were more likely than controls to be female, younger, younger when entering service, never married, and have a recent mental health diagnosis. Risk among enlisted soldiers peaked in the second month of service and declined steadily, whereas risk among officers remained relatively stable over time. Risk of SI is highest among enlisted soldiers early in Army service, females, and those with a recent mental health diagnosis.     

Coordinated Rational Choice

Topoi - When acting in social contexts, we are often able to voluntarily coordinate our choices with one another. It has been suggested that this ability relies on the adoption of preferences that...