Unconscious modulation of the conscious experience of voluntary control

How does the brain generate our experience of being in control over our actions and their effects? Here, we argue that the perception of events as self-caused emerges from a comparison between anticipated and actual action-effects: if the representation of an event that follows an action is activated before the action, the event is experienced as caused by one's own action, whereas in the case of a mismatch it will be attributed to an external cause rather than to the self. In a subliminal priming paradigm we show that participants overestimated how much control they had over objectively uncontrollable stimuli, which appeared after free- or forced-choice actions, when a masked prime activated a representation of the stimuli immediately before each action. This prime-induced control-illusion was independent from whether primes were consciously perceived. Results indicate that the conscious experience of control is modulated by unconscious anticipations of action-effects.     

Periodicities within a fixed-interval session

Within-session periodicities in number of responses per interval and postreinforcement pauses were investigated on fixed-interval schedules of 1, 2, and 3 minutes with rats. Postreinforcement pause values and the number of responses in successive intervals were not systematically related. The direction of change of these variables from one pair of intervals to the next revealed periodicities in that the direction of change varied more than would be expected by chance. A response prevention technique used to manipulate the length of time spent responding in an interval had little effect on the postreinforcement pause value of the next interval except when only a single response was permitted in an interval. This procedure tended to reduce the postreinforcement pause value of the next interval to an abnormally low level.     

Performance predictions affect attentional processes of event-based prospective memory

To investigate whether making performance predictions affects prospective memory (PM) processing, we asked one group of participants to predict their performance in a PM task embedded in an ongoing task and compared their performance with a control group that made no predictions. A third group gave not only PM predictions but also ongoing-task predictions. Exclusive PM predictions resulted in slower ongoing-task responding both in a nonfocal (Experiment 1) and in a focal (Experiment 2) PM task. Only in the nonfocal task was the additional slowing accompanied by improved PM performance. Even in the nonfocal task, however, was the correlation between ongoing-task speed and PM performance reduced after predictions, suggesting that the slowing was not completely functional for PM. Prediction-induced changes could be avoided by asking participants to additionally predict their performance in the ongoing task. In sum, the present findings substantiate a role of metamemory for attention-allocation strategies of PM.     

Dissociations and associations of performance in syntactic comprehension in aphasia and their implications for the nature of aphasic deficits

Sixty-one pwa were tested on syntactic comprehension in three tasks: sentence-picture matching, sentence-picture matching with auditory moving window presentation, and object manipulation. There were significant correlations of performances on sentences across tasks. First factors on which all sentence types loaded in unrotated factor analyses accounted for most of the variance in each task. Dissociations in performance between sentence types that differed minimally in their syntactic structures were not consistent across tasks. These results replicate previous results with smaller samples and provide important validation of basic aspects of aphasic performance in this area of language processing. They point to the role of a reduction in processing resources and of the interaction of task demands and parsing and interpretive abilities in the genesis of patient performance.     

Nanoindentation study of size effects in nickel–graphene nanocomposites

Metal–graphene nanocomposites find applications in nanoscale devices, as functional materials and can serve as a test bed to gain insight into fundamental deformation mechanisms of metals under geometric confinement. Here, we report full atomistic nanoindentation simulations for nickel–graphene nanocomposites with varied numbers of layers of graphene sheets to investigate the size effects on the hardness, and to understand how emerging dislocation loops interact with the nickel–graphene interface under varied geometric confinements. A detailed analysis of the plastic deformation mechanism shows that as dislocation loops reach the nickel–graphene interface, the local bending of the graphene sheet is altered and further dislocation propagation is blocked. An increase in the number of graphene layers decreases the hardness, but increases the maximum elastic deformation of the nickel–graphene nanocomposites. These findings indicate that the mechanical properties of nickel–graphene nanocomposites can be engineered by controlling the thickness of nickel and graphene layers, respectively.     

Temporal preparation,response inhibition and impulsivity

Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a temporal preparation go no-go task. This task measured, in less than 10 min, how response inhibition was influenced both by temporal orienting of attention (guided by predictive temporal cues) and by sequential effects (produced by repetition/alternation of the duration of preparatory intervals in consecutive trials). The results showed that sequential effects produced dissociable patterns of temporal preparation as a function of impulsivity. Sequential effects facilitated both response speed (reaction times – RTs – to the go condition) and response inhibition (false alarms to the no-go condition) selectively in the low impulsivity group. In the high impulsivity group, in contrast, sequential effects only improved RTs but not response inhibition. We concluded that both excitatory and inhibitory processing may be enhanced concurrently by sequential effects, which enables the temporal preparation of fast and controlled responses. Impulsivity could hence be related to less efficient temporal preparation of that inhibitory processing.     

Dissociating the effects of angular disparity and image similarity in mental rotation and object recognition

Performance is often impaired linearly with increasing angular disparity between two objects in tasks that measure mental rotation or object recognition. But increased angular disparity is often accompanied by changes in the similarity between views of an object, confounding the impact of the two factors in these tasks. We examined separately the effects of angular disparity and image similarity on handedness (to test mental rotation) and identity (to test object recognition) judgments with 3-D novel objects. When similarity was approximately equated, an effect of angular disparity was only found for handedness but not identity judgments. With a fixed angular disparity, performance was better for similar than dissimilar image pairs in both tasks, with a larger effect for identity than handedness judgments. Our results suggest that mental rotation involves mental transformation procedures that depend on angular disparity, but that object recognition is predominately dependent on the similarity of image features.     

Testing the differential effects of changes in psychological contract breach and fulfillment

Rousseau (1989 and elsewhere) argued that a defining feature of psychological contract breach was that once a promise had been broken it could not easily be repaired and therefore that the effects of psychological contract breach outweighed those of psychological contract fulfillment. Using two independent longitudinal surveys, this paper investigated whether changes in breach and fulfillment differentially affected work-related attitudes and affective well-being outcomes. Results generally supported differential effects, where increases in reported breach had greater effects on outcomes than increases in fulfillment, for the outcomes of affective wellbeing, job satisfaction, and organizational commitment. The present study underlined the importance of breach as a determinant of negative affect and attitudes. However, fulfillment had a lesser impact, in that it maintained (i.e., had no effect) or had only a modest positive effect on wellbeing and attitudes.     

A randomized trial to evaluate the course of effects of a program to prevent adolescent depressive symptoms over 12 months

Although few prevention studies have been designed to investigate the course of prevention effects over time, it seems that the effects on depressive symptoms increase from post-intervention to 6-month follow-up but then decrease with longer lags to follow-up. Furthermore, previous prevention studies have found differential intervention effects for boys and girls without testing possible explanations for this effect. The present randomized control group study with 301 8th-grade students examined the effects of a depression prevention program from baseline until 12-month follow-up. As expected, while positive intervention effects were found on girls’ depressive symptoms, no such effects were found on boys’ depressive symptoms. Further, the positive intervention effects on girls’ depressive symptoms increased to the 6-month follow-up and remained stable through the 12-month follow-up, while depression symptoms in control-group girls increased from 6-month to 12-month follow-up. Further exploratory analyses revealed that neither baseline conduct problems nor cognitive or social knowledge of the prevention program at 12-month follow-up alone explained the sex effect. However, some limited evidence was found indicating that total knowledge (cognitive and social) might partially explain the effect but there was significant variability remaining to be explained.     

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Abstract

Social comparisons in a real intergroup context involving Anglophones and Francophones from Quebec, Canada, were examined. Three hypotheses were proposed: A variety of potential comparisons arise in an intergroup context, three different motivations for social comparison in an intergroup situation (reality testing, group enhancement, equity appeal) are associated with predictably different targets for comparison, and social comparisons are linked to feelings and actions. Some support for all three hypotheses was found. We suggest that the major dilemmas confronting social comparison theory could be approached more effectively if researchers studying comparisons at the individual level and those interested in intergroup comparisons worked more in concert.