Neuroticism as mental noise: a relation between neuroticism and reaction time standard deviations

Those higher in neuroticism are often more variable in their behavior and experience. On the basis of this observation, the authors hypothesized that the trait of neuroticism might be correlated with the variability of performance pertaining to relatively basic cognitive operations. Three studies involving 242 college undergraduates supported this prediction in that neuroticism correlated positively with the variability of performance across trials of reaction time tasks. These results link neuroticism to cognitive noise that intervenes between stimulus and response. Such noise has been associated with executive dysfunctions (e.g., frontal lobe injury) in previous research. The present findings are potentially useful for understanding why neuroticism often correlates with variations in the functionality of cognition and behavior.     

Rightward biases in free-viewing visual bisection tasks: implications for leftward responses biases on similar tasks

Neurologically normal individuals exhibit strong leftward response biases during free-viewing perceptual judgments of brightness, quantity, and size. When participants view two mirror-reversed objects and they are forced to choose which object appears darker, more numerous, or larger, the stimulus with the relevant feature on the left side is chosen 60-75% of the time. This effect could be influenced by inaccurate judgments of the true centre-point of the objects being compared. In order to test this possibility, 10 participants completed three visual bisection tasks on stimuli known to elicit strong leftward response biases. Participants were monitored using a remote eye-tracking device and instructed to stare at the subjective midpoint of objects presented on a computer screen. Although it was predicted that bisection errors would deviate to the left of centre (as is the case in the line bisection literature), the opposite effect was found. Significant rightward bisection errors were evident on two of the three tasks, and the leftward biases seen during forced-choice tasks could be the result of misjudgments to the right of centre on these same tasks.     

Construct validity of the Balloon Analog Risk Task (BART): associations with psychopathy and impulsivity

To continue research assessing the validity of the Balloon Analog Risk Task (BART) as a measure of risk taking, the BART was administered to a nonforensic sample of individuals with varying levels of psychopathic characteristics. Construct validity of the BART was evaluated by measuring risk-taking behavior in relation to self-reported psychopathy, anxiety, psychophysiological data, and demographic variables. Supporting the construct validity of the BART, while controlling for variance accounted for by interrelated variables in the context of hierarchical regression analyses, higher self-reported psychopathy was significantly predictive of increased risk taking on the BART. Findings also revealed interesting gender differences in self-reported psychopathy and a trend for men to engage in riskier behavior. Limitations and research directions are presented.     

Enhancement of auditory fear conditioning after housing in a complex environment is attenuated by prior treatment with amphetamine

Prior exposure to drugs of abuse has been shown to occlude the structural plasticity associated with living in a complex environment. Amphetamine treatment may also occlude some cognitive advantages normally associated with living in a complex environment. To test this hypothesis we examined the influence of prior exposure to amphetamine on fear conditioning in rats housed in either a standard or complex environment. Housing in a complex environment facilitated fear learning to an auditory conditioned stimulus (CS), but not to the training context, relative to animals housed singly or in a social group. Prior treatment with amphetamine eliminated this effect. These results indicate that living in a complex environment facilitates conditional freezing to an auditory CS, and that this effect is abolished by pretreatment with amphetamine.     

Cognitive behaviour therapy for panic disorder: long-term follow-up

This paper describes a long-term follow-up of patients with panic disorder who received cognitive behaviour therapy within a randomized controlled trial. Of 89 patients eligible for follow-up, 28 (31.5%) were reassessed 6-8 years after commencement of treatment in the trial. No differences were found between those who were followed up and those lost to follow-up on most baseline measures including measures of panic-related psychopathology, or depression. Outcomes at long-term follow-up were significantly better than baseline measures of panic, avoidance and depression. In this sub-sample the effect of cognitive behaviour therapy for panic disorder appears to maintain over the long-term.     

Impact of recent findings on study design of future autism clinical trials

There are specific challenges to studying the design of pharmacologic trials in child/adolescent and adult autism, such as subject stratification and parallel versus crossover designs. This article describes how optimal study design is influenced by subject selection and outcome measures chosen. Lessons learned in study design from the Research Units on Pediatric Psychopharmacology Autism Network trial with risperidone, Seaver Center trials with fluoxetine and valproate, Dartmouth trials with amantadine, and National Institutes of Health secretin trials are highlighted. The Internet System for Assessing Autistic Children system for managing multicenter clinical trials in autism and statistical issues in autism research are also described.     

Spatial reference and scanning with the left and right hand

Discrepant findings on performance by the two hands in spatial tasks make it difficult to infer spatial coding unambiguously. We tested the hypotheses (a) that the left hand is consistently better in haptic spatial tasks and (b) that adding spatial reference information produces more accurate coding in spatial tasks, independently task and hand effects. Instructions to use external cues from a surrounding frame as well as body-centred cues for reference produced highly significant increases in accuracy in haptic distance and location experiments. The distance experiments showed no hand differences. A small right-hand advantage with longer positioning movements in the recall of locations was significant when combined with left-hand scanning of the frame, but did not relate to reference conditions. Hand use interacted significantly with the location-versus-distance experiments, but showed no interaction with the spatial reference factor, which was highly significant in both experiments. The finding suggests that modes of coding need to be distinguished from cross-lateral effects of sensory input conditions. The study shows that varying reference information offers a potentially useful behavioural tool for distinguishing spatial coding from input and task conditions independently of hand performance. Methodological, practical, and theoretical implications are discussed.     

Children's difficulties handling dual identity

Thirty-nine 6-year-old children participated in a longitudinal study using tasks that required handling of dual identity. Pre- and posttest sessions employed tasks involving a protagonist who was partially informed about an object or person; for example, he knew an item as a ball but not as a present. Children who judged correctly that the protagonist did not know the ball was a present (thereby demonstrating some understanding of the consequences of limited information access), often judged incorrectly (1) that he knew that there was a present in the box, and (2) that he would search as if fully informed. Intervening sessions added contextual support and tried to clarify the experimenter's communicative intentions in a range of ways. Despite signs of general improvement, the distinctive pattern of errors persisted in every case. These findings go beyond previous studies of children's handling of limited information access, and are hard to accommodate within existing accounts of developing understanding of the mind.