36 research outputs found
Evaluation of Hylleraas-CI atomic integrals by integration over the coordinates of one electron. IV. An improved algorithm for three-electron kinetic energy integrals
An improved algorithm to evaluate the nonrelativistic three-electron
Hylleraas-Configuration Interaction (Hy-CI) kinetic energy integrals over
Slater orbitals and the Hamiltonian in Hylleraas coordinates is shown. The
resulting analytical expressions are general for all quantum numbers of the
orbitals. From there, the restriction of employing orbitals with quantum
numbers of the above algorithm presented in paper I of this series
has been removed. With the new algorithm it is possible, in the direct
integration method described in this series, to carry out Hy-CI atomic
structure calculations including -, -, , and higher
angular-momentum Slater orbitals and to determine , , , and
states of higher order symmetry.Comment: 32 pages, 14 references, 1 figure and 1 table, Journal of
Mathematical Chemistry, January 201
Context specificity of post-error and post-conflict cognitive control adjustments
There has been accumulating evidence that cognitive control can be adaptively regulated by monitoring for processing conflict as an index of online control demands. However, it is not yet known whether top-down control mechanisms respond to processing conflict in a manner specific to the operative task context or confer a more generalized benefit. While previous studies have examined the taskset-specificity of conflict adaptation effects, yielding inconsistent results, controlrelated performance adjustments following errors have been largely overlooked. This gap in the literature underscores recent debate as to whether post-error performance represents a strategic, control-mediated mechanism or a nonstrategic consequence of attentional orienting. In the present study, evidence of generalized control following both high conflict correct trials and errors was explored in a task-switching paradigm. Conflict adaptation effects were not found to generalize across tasksets, despite a shared response set. In contrast, post-error slowing effects were found to extend to the inactive taskset and were predictive of enhanced post-error accuracy. In addition, post-error performance adjustments were found to persist for several trials and across multiple task switches, a finding inconsistent with attentional orienting accounts of post-error slowing. These findings indicate that error-related control adjustments confer a generalized performance benefit and suggest dissociable mechanisms of post-conflict and post-error control. © 2014 Forster, Cho
When specific action biases meet nonspecific preparation: Event repetition modulates the variable-foreperiod effect
Preparing for the moment of action speeds up reaction time (RT) performance even if the particular response is unknown beforehand. When the preparatory interval, or foreperiod (FP), varies unpredictably between trials, responses usually become faster with increasing FP length. This variable-FP effect has been demonstrated to partly originate from trial-to-trial sequential effects of FP length, which are asymmetric as they occur mainly in short-FP but not in long-FP trials. In two experiments, we examined whether and how event-specific biases arising from previous target processing and responding affect both variable-FP and sequential FP effects. We found that trial-to-trial repetitions (vs. alternations) of imperative events produced response time benefits in short-FP but not in long-FP trials, almost eliminating the variable-FP effect, while the sequential FP effect remained intact. This asymmetric contribution to speeded performance in variable-FP settings suggests that sequential event-specific biases may be highly transient and not necessarily an integral part of the mental representations that guide time-based expectancy, or may be overridden by high levels of nonspecific preparation in long-FP trials. In conclusion, temporal preparation appears to be a nonspecific mechanism (i.e., generally not bound to particular event features) for prioritizing certain positions on the mental time line, on which event-specific short-term biases are superimposed if time-based preparation is weak. (PsycINFO Database Record
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Positive expectations predict improved mental-health outcomes linked to psychedelic microdosing
Psychedelic microdosing describes the ingestion of near-threshold perceptible doses of classic psychedelic substances. Anecdotal reports and observational studies suggest that microdosing may promote positive mood and well-being, but recent placebo-controlled studies failed to find compelling evidence for this. The present study collected web-based mental health and related data using a prospective (before, during and after) design. Individuals planning a weekly microdosing regimen completed surveys at strategic timepoints, spanning a core four-week test period. Eighty-one participants completed the primary study endpoint. Results revealed increased self-reported psychological well-being, emotional stability and reductions in state anxiety and depressive symptoms at the four-week primary endpoint, plus increases in psychological resilience, social connectedness, agreeableness, nature relatedness and aspects of psychological flexibility. However, positive expectancy scores at baseline predicted subsequent improvements in well-being, suggestive of a significant placebo response. This study highlights a role for positive expectancy in predicting positive outcomes following psychedelic microdosing and cautions against zealous inferences on its putative therapeutic value
Mobilizing cognition for speeded action: try-harder instructions promote motivated readiness in the constant-foreperiod paradigm
We examined the effect of motivational readiness on cognitive performance. An important but still not sufficiently elaborated question is whether individuals can voluntarily increase cognitive efficiency for an impending target event, given sufficient preparation time. Within the framework of the constant-foreperiod design (comparing reaction time performance in blocks of short and long foreperiod intervals, FPs), we examined the effect of an instruction to try harder (instructional cue: standard vs. effort) in a choice-reaction task on performance speed and variability. Proceeding from previous theoretical considerations, we expected the instruction to speed-up processing irrespective of FP length, while error rate should be increased in the short-FP but decreased in the long-FP condition. Overall, the results confirmed this prediction. Importantly, the distributional (ex-Gaussian and delta plot) analysis revealed that the instruction to try harder decreased distributional skewness (i.e., longer percentiles were more affected), indicating that mobilization ensured temporal performance stability (persistence)