The influence of accuracy as a function of leader's bias: the role of trustworthiness in the psychology of procedural justice

The present research examined the combined effect of accuracy of procedures and leader's bias on fairness judgments and the experience of positive emotions. The results of two studies showed that the strongest positive effects on both types of reactions were found when procedures were accurate and the leader was unbiased. In addition, accuracy of procedures only revealed an impact when the leader was perceived as unbiased rather than biased. Moreover, this interactive effect was found to be mediated, at least partly, by perceptions of trustworthiness. These findings show that more research is needed on examining different types of procedural fairness, both as single and combined predictors of people's reactions.     

Performing the vertical jump: movement adaptations for submaximal jumping

The purpose of this study was to gain insight into the kinematics and kinetics of the vertical jump when jumping for different heights and to investigate movement effectiveness as a criterion for movement control in submaximal jumping. In order to jump high a countermovement is used and large body segments are rotated, both of which consume energy which is not directly used to gain extra jump height. It was hypothesized that the energy used to reach a specified jump height is minimized by limiting the non-effective energy consumed. Standing vertical jumps attempting 100%, 75%, 50%, and 25% of maximal height were performed by a group of 10 subjects. Force and motion data were recorded simultaneously during each performance. We found that jump height increased due to increasing vertical velocity at take off. This was primarily related to an increase in countermovement amplitude. As such, flexion amplitude of the hip joint increased with jump height whereas the ankle and knee joint flexion did not. These findings revealed that for submaximal jumping a consistent strategy was used of maximizing the contribution of distal joints and minimizing the contribution of proximal joints. Taking into account the high inertia of proximal segments, the potential energy deficit due to countermovement prior to joint extension, the advantageous horizontal orientation of the foot segment during stance and the tendon lengths in distal muscles, it was concluded that movement effectiveness is a likely candidate for the driving criterion of this strategy.     

Kicking coordination captures differences between full-term and premature infants with white matter disorder

This study explores the relation of white matter disorder (WMD) to intralimb coordination patterns in premature infants with very low birth weight (VLBW). We specifically measured the temporal-spatial characteristics of intralimb coordination patterns of the legs. Three groups of infants were compared at one month corrected age (CA): 10 premature infants born VLBW and WMD (PTWMD), 10 premature infants born VLBW without WMD (PT) and 10 full term infants (FT). Using kinematic variables, we discriminate among VLBW infants with WMD from the two comparison groups. Infants born with WMD maintain patterns of tight coupling among leg joints (all flexion or all extension) while PT and FT term infants have begun to decouple leg joints by this age (combinations of flexion with extension). The coupling pattern is captured through joint correlations, discrete relative phase, and phase plane portraits. The PTWMD infants also demonstrate aberrant patterns of coordination evident through both temporal and spatial characteristics of the kicks. This is the first evidence that movement disorder associated with brain lesions can be identified and quantified with kinematic variables as early as one month of age.     

Spatial Simon effects with nonspatial responses

Recent studies have shown that spatial Simon effects can be modulated by short-term associations that are set up as a result of task instructions. I examined whether spatial Simon effects can also be produced by short-term associations even when the responses are unrelated to spatial position. Participants were to say “cale” or “cole” on the basis of the direction of arrows (i.e., left or right), the meaning of words (i.e.,left orright), and the color of squares presented left or right of the screen center. Responses to squares were faster when the correct response was associated with the same position as the irrelevant position of the square (e.g., say “cale” to a square on the left when “cale” was assigned to the wordleft and the left arrow). This new type of stimulus-response compatibility effect provides the first evidence for short-term associations that involve mode-independent representations.     

Coordinate high-frequency pattern of stimulation and calcium levels control the induction of LTP in striatal cholinergic interneurons

Current evidence appoints a central role to cholinergic interneurons in modulating striatal function. Recently, a long-term potentiation (LTP) of synaptic transmission has been reported to occur in these neurons. The relationship between the pattern of cortico/thalamostriatal fibers stimulation, the consequent changes in the intracellular calcium concentration ([Ca2+]i), and the induction of synaptic plasticity was investigated in striatal cholinergic interneurons from a rat corticostriatal slice preparation by means of combined electrophysiological intracellular recordings and microfluorometric techniques. Different protocols of stimulation were considered, varying both the frequency and the duration of the train of stimuli. High-frequency stimulation (HFS) (three trains at 100 Hz for 3 sec, 20-sec interval) induced a rise in [Ca2+]i, exceeding by fivefold the resting level, and caused a LTP of synaptic transmission. Tetanic stimulation delivered at lower frequencies (5-30 Hz) failed to induce long-term changes of synaptic efficacy. The observed elevation in [Ca2+]i during HFS was primarily mediated by L-type high-voltage activated (HVA)-Ca2+ channels, as it was fully prevented by nifedipine. Conversely, blockade of NMDA and AMPA glutamate receptor did not affect either LTP or the magnitude of the [Ca2+]i rise. Interestingly, the pharmacological analysis of the post-tetanic depolarizing postsynaptic potential (DPSP) revealed that LTP was attributable, to a large extent, to the potentiation of the GABA(A)-mediated component. In conclusion, the expression of LTP in striatal cholinergic interneurons is a selective response to a precise stimulation pattern of induction requiring a critical rise in [Ca2+]i.     

Preference and performance measures of handedness

Handedness cannot be predicted using a single performance measure, and preference measures of handedness are unreliable because of their subjectivity. This report was designed to examine the relationship between hand performance and hand preference using six different measures: the Waterloo Handedness Questionnaire (a measure of hand preference), the Wathand Box (a performance-based indicator of hand preference), two pegboard tasks, finger tapping, and grip strength and to determine the most accurate performance-based predictor of hand preference as measured by the Waterloo Handedness Questionnaire. Multiple linear regression analysis showed that together, the Wathand Box score and the lateralized place phase of the grooved pegboard task were the most accurate predictors of hand preference.     

Imposing structure on a Corsi-type task: evidence for hierarchical organisation based on spatial proximity in serial-spatial memory

Structure was imposed on a tapping task by requiring participants to reproduce sequences of responses to icons organised in spatial clusters. A first experiment featured sequences either segregated or not segregated by clusters. Accuracy was higher for sequences segregated by clusters. Moreover, inter-response times were longer at cluster boundaries than within cluster boundaries. To rule out possible confounding effects of movement length, this temporal pattern was replicated in a second experiment requiring a single response indicating the next sequential step, following the presentation of a portion of a previously practised sequence. These results suggest that sequence reproduction can be sustained by a hierarchical representation based on spatial proximity and provide a first indication of the role of spatial structure in serial-spatial memory.     

The effects of skill demands and object position on the distribution of preferred hand reaches

Performance-based measures of hand preference have been developed as an objective method of examining handedness. Previous research using this method showed that both skill demands and the position of the object in working space affect preferential hand reaching. Specifically, preferred hand reaches predominated in left hemispace, in spite of the biomechanical inefficiency involved in reaching across the body midline. This was mediated by the skill demands, with a higher frequency of preferred hand reaches for tasks requiring more skill. To further examine this issue, we increased the task skill demands. Twenty-two right-handed adults reached for five tools located in an array of five positions in front of them. Participants were required to pick up the tool, pick up and demonstrate how to use it, or pick up and actually use the tool on the materials provided. The results showed that the frequency of right hand reaches was greatest for the tool use condition. This effect was mediated by the position of the object in hemispace, with more right hand reaches occurring for the Use task in left hemispace than the other tasks, in support of our previous work.     

Impaired performance of children exposed in utero to cocaine on a novel test of visuospatial working memory

The present study examines the potentially harmful effects of prenatal cocaine exposure on later visuospatial memory functions. A novel neuropsychological measure of immediate- and short-term memory for visuospatial information was administered to 40 children, who were identified as cocaine-exposed, and 11 age and socioeconomic status matched controls (all children were 8-9 years old). The Groton Maze Learning Test is a computer-based hidden maze learning test that consists of a 'timed chase test' (a simple measure of visuomotor speed), 5 learning trials on a hidden maze, followed by a delayed recall trial after an 8 min delay. The specific test parameters are chosen based on the age cohort of the subjects. The cocaine-exposed group performed significantly slower on the 'timed chase test,' the last 3 learning trials, and the delayed recall trial (p < or = .05 for all comparisons). Although there was a modest trend for the cocaine-exposed group to make more errors throughout the learning trials, there were no significant group differences. These results suggest that children who were exposed in utero to cocaine exhibit slowed visuomotor speed, a possible impairment in procedural learning, and diminished efficiency in accessing and using the internal spatial map that subjects create to master the maze.