How dynamic is interhemispheric interaction? Effects of task switching on the across-hemisphere advantage

Interaction between the cerebral hemispheres may allow both hemispheres to contribute their processing resources in order to cope efficiently with complex tasks [Banich, M. (1998). The missing link: the role of interhemispheric interaction in attentional processing. Brain and Cognition, 36, 128-157]. The current study investigated whether the benefits of interhemispheric interaction arise because of top-down knowledge about the task built up over the course of a block of trials or because of the processing demands present in a single trial. Participants performed a less computationally complex physical identity task and a more complex adding task on within-visual field and across-visual field trials. Task differences in interhemispheric interaction were compared between the blocked and mixed conditions to investigate whether frequent task switches altered the pattern of interhemispheric resource recruitment. A similar interaction between task difficulty and trial type (across- or within-visual field presentation) was obtained for both the blocked and mixed conditions. The degree of task-dependency of interhemispheric interaction was not altered in the mixed condition. This finding supports the view that interhemispheric interaction becomes beneficial in response to the processing demands of an individual trial rather than as a result of top-down task knowledge.     

海洛因戒除者的行为冲动性： 基于DDT和IGT任务反应模式的探讨

以61名男性海洛因戒除者和32名正常成年男性为被试,探讨了海洛因戒除者在延迟折扣任务和Iowa赌博任务两种决策条件下的冲动性反应模式及其关系。结果发现,海洛因戒除者的决策行为受其对即时强化的超敏感性或“即时收益优先”模式控制,其高冲动性特质既表现为对强化物长远价值的非敏感性,又表现为对强化物潜在风险的耐受性;该类人群上述两方面的特征虽有一定关联,但二者分别反应了其行为冲动性的两个相对独立的维度,且具有跨戒除时相的相对稳定性     

大学生感恩内隐效应的实验研究

研究探讨内隐联想测验(Implicit Association Test,IAT)和Go/No-go联想任务测验(Go/No-go Association Task, GNAT)测量大学生感恩的可行性,并分析内隐感恩与外显感恩的关系。预备性研究从现代汉语字典中挑选自我词/他人词各16个,从汉语成语大辞典中挑选出与感恩相关的积极词/消极词各20个,根据65位大学生的评定结果筛选出自我词/他人词各8个,积极词/消极词各8个,用于正式研究。正式研究采用IAT、GNAT感恩测量程序和青少年感恩量表(Adolescent Gratitude Scale,AGS),对155名大学生同时进行IAT、GNAT及外显感恩的测量。结果发现:(1)大学生普遍具有积极的内隐感恩,内隐感恩不存在性别、生源地和独生与否等人口统计学指标上的显著差异;(2)大学生的内隐感恩与外显感恩相关不显著,是两个不同的建构;(3)采用IAT和GNAT研究感恩是可行的。     

Age-related variance in decisions under ambiguity is explained by changes in reasoning,executive functions,and decision-making under risk

Previous literature has explained older individuals’ disadvantageous decision-making under ambiguity in the Iowa Gambling Task (IGT) by reduced emotional warning signals preceding decisions. We argue that age-related reductions in IGT performance may also be explained by reductions in certain cognitive abilities (reasoning, executive functions). In 210 participants (18–86 years), we found that the age-related variance on IGT performance occurred only in the last 60 trials. The effect was mediated by cognitive abilities and their relation with decision-making performance under risk with explicit rules (Game of Dice Task). Thus, reductions in cognitive functions in older age may be associated with both a reduced ability to gain explicit insight into the rules of the ambiguous decision situation and with failure to choose the less risky options consequently after the rules have been understood explicitly. Previous literature may have underestimated the relevance of cognitive functions for age-related decline in decision-making performance under ambiguity.     

Core self-evaluations as a moderator of the relationship between task complexity,job resources,and performance

In this study we examined the role of trait core self-evaluations (CSE) as a person-related resource, hypothesizing that the relationship between task complexity and performance would be positive for people high in trait CSE and negative for people low in trait CSE. Moreover, we hypothesized that trait CSE would influence the buffering effect of job-related resources on the complexity–performance relationship, with such a buffering effect showing for people high but not for people low in trait CSE. To test our hypotheses, we conducted a five-day spanning experience sampling study. Our results showed that trait CSE indeed influenced the complexity–performance relationship in the sense that this relationship was only positive for employees high in CSE. Results on the hypothesized three-way interaction between task complexity, job-related resources, and CSE were less univocal as only one out of four three-way interactions approached conventional levels of significance. By showing that the complexity–performance relationship is only positive for employees high in CSE, our results go against the well-accepted idea that challenge demands act as a two-edged sword for all employees alike. Instead, the effect of challenge demands on performance depends on the individual’s level of person-related resources.     

Shielding voices: The modulation of binding processes between voice features and response features by task representations

Vocal events offer not only semantic-linguistic content but also information about the identity and the emotional-motivational state of the speaker. Furthermore, most vocal events have implications for our actions and therefore include action-related features. But the relevance and irrelevance of vocal features varies from task to task. The present study investigates binding processes for perceptual and action-related features of spoken words and their modulation by the task representation of the listener. Participants reacted with two response keys to eight different words spoken by a male or a female voice (Experiment 1) or spoken by an angry or neutral male voice (Experiment 2). There were two instruction conditions: half of participants learned eight stimulus-response mappings by rote (SR), and half of participants applied a binary task rule (TR). In both experiments, SR instructed participants showed clear evidence for binding processes between voice and response features indicated by an interaction between the irrelevant voice feature and the response. By contrast, as indicated by a three-way interaction with instruction, no such binding was found in the TR instructed group. These results are suggestive of binding and shielding as two adaptive mechanisms that ensure successful communication and action in a dynamic social environment.     

Back to the future: autobiographical planning and the functionality of mind-wandering

Given that as much as half of human thought arises in a stimulus independent fashion, it would seem unlikely that such thoughts would play no functional role in our lives. However, evidence linking the mind-wandering state to performance decrement has led to the notion that mind-wandering primarily represents a form of cognitive failure. Based on previous work showing a prospective bias to mind-wandering, the current study explores the hypothesis that one potential function of spontaneous thought is to plan and anticipate personally relevant future goals, a process referred to as autobiographical planning. The results confirm that the content of mind-wandering is predominantly future-focused, demonstrate that individuals with high working memory capacity are more likely to engage in prospective mind-wandering, and show that prospective mind-wandering frequently involves autobiographical planning. Together this evidence suggests that mind-wandering can enable prospective cognitive operations that are likely to be useful to the individual as they navigate through their daily lives.     

Inverse association between dopaminergic neurotransmission and Iowa Gambling Task performance in pathological gamblers and healthy controls

Linnet, J., Møller, A., Peterson, E., Gjedde, A. & Doudet, D. (2011). Inverse association between dopaminergic neurotransmission and Iowa Gambling Task performance in pathological gamblers and healthy controls. Scandinavian Journal of Psychology 52, 28–34. The dopamine system is believed to affect gambling behavior in pathological gambling. Particularly, dopamine release in the ventral striatum appears to affect decision‐making in the disorder. This study investigated dopamine release in the ventral striatum in relation to gambling performance on the Iowa Gambling Task (IGT) in 16 Pathological Gamblers (PG) and 14 Healthy Controls (HC). We used Positron Emission Tomography (PET) to measure the binding potential of [¹¹C] raclopride to dopamine D2/3 receptors during a baseline and gambling condition. We hypothesized that decreased raclopride binding potentials in the ventral striatum during gambling (indicating dopamine release) would be associated with higher IGT performance in Healthy Controls, but lower IGT performance in Pathological Gamblers. The results showed that Pathological Gamblers with dopamine release in the ventral striatum had significantly lower IGT performance than Healthy Controls. Furthermore, dopamine release was associated with significantly higher IGT performance in Healthy Controls and significantly lower IGT performance in Pathological Gamblers. The results suggest that dopamine release is involved both in adaptive and maladaptive decision‐making. These findings may contribute to a better understanding of dopaminergic dysfunctions in pathological gambling and substance related addictions.     

Brief and rare mental “breaks” keep you focused: Deactivation and reactivation of task goals preempt vigilance decrements

We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from ever habituating. We asked observers to perform a visual vigilance task while maintaining digits in-memory. When observers retrieved the digits at the end of the vigilance task, their vigilance performance steeply declined over time. However, when observers were asked to sporadically recollect the digits during the vigilance task, the vigilance decrement was averted. Our results present a direct challenge to the pervasive view that vigilance decrements are due to a depletion of attentional resources and provide a tractable mechanism to prevent this insidious phenomenon in everyday life.     

Transfer of short-term motor learning across the lower limbs as a function of task conception and practice order

Interlimb transfer of motor learning, indicating an improvement in performance with one limb following training with the other, often occurs asymmetrically (i.e., from non-dominant to dominant limb or vice versa, but not both). In the present study, we examined whether interlimb transfer of the same motor task could occur asymmetrically and in opposite directions (i.e., from right to left leg vs. left to right leg) depending on individuals’ conception of the task. Two experimental conditions were tested: In a dynamic control condition, the process of learning was facilitated by providing the subjects with a type of information that forced them to focus on dynamic features of a given task (force impulse); and in a spatial control condition, it was done with another type of information that forced them to focus on visuomotor features of the same task (distance). Both conditions employed the same leg extension task. In addition, a fully-crossed transfer paradigm was used in which one group of subjects initially practiced with the right leg and were tested with the left leg for a transfer test, while the other group used the two legs in the opposite order. The results showed that the direction of interlimb transfer varied depending on the condition, such that the right and the left leg benefited from initial training with the opposite leg only in the spatial and the dynamic condition, respectively. Our finding suggests that manipulating the conception of a leg extension task has a substantial influence on the pattern of interlimb transfer in such a way that the direction of transfer can even be opposite depending on whether the task is conceived as a dynamic or spatial control task.