How positive affect modulates cognitive control: Reduced perseveration at the cost of increased distractibility

A fundamental problem that organisms face in a changing environment is how to regulate dynamically the balance between stable maintenance and flexible switching of goals and cognitive sets. The authors show that positive affect plays an important role in the regulation of this stability–flexibility balance. In a cognitive set-switching paradigm, the induction of mild increases in positive affect, as compared with neutral or negative affect, promoted cognitive flexibility and reduced perseveration, but also incurred a cost in terms of increased distractibility. Rather than influencing set switching in an unspecific way, positive affect thus exerted opposite effects on perseveration and distractibility. Results are consistent with neuropsychological models according to which effects of positive affect on cognitive control are mediated by increased dopamine levels in frontal brain areas. Intelligent organisms pursuing goal-directed behavior in a con-stantly changing environment face two fundamental challenges: to maintain current goals over time in the face of distraction on the one hand, and to flexibly switch between goals and update working memory in response to significant changes on the other (Goschke, 1996, 2000, 2003; cf. Mayr & Keele, 2000; O’Reilly, Braver, &amp

The role of task-rules and stimulus-response mappings in the task switching paradigm

Switch costs occur whenever participants are asked to switch between two or more task sets. In a typical task switching experiment, participants have to switch between two task sets composed of up to four different stimuli per task set. These 2 (task sets) × 4 (stimuli) contain only 8 different stimulus–response (S–R) mappings, and the question is why participants base their task performance on task sets instead of S–R mappings. The current experiments compared task performance based on task rules with performance based on single stimulus–response mappings. Participants were led to learn eight different S–R mappings with or without foreknowledge about two underlying task sets. Without task set information no difference between shifts and repetitions occurred, whereas introducing task sets at the beginning led to significant switch costs. Most importantly, introducing task sets in the middle of the experiment also resulted in significant switch costs. Furthermore, introducing task rules at the beginning of the experiment lead to slower RTs when simple stimuli (Experiment 1) had to be processed. This detrimental effect disappeared with more complex stimuli (Experiment 2). Results will be discussed with respect to cognitive control

Context-sensitive adjustments of cognitive control: Conflict-adaptation effects are modulated by processing demands of the ongoing task

Dynamic adjustments of cognitive control in response to interference from irrelevant stimulus attributes have repeatedly been shown. The purpose of the current research was to investigate how these control adjustments are modulated by the processing demands of a primary task. To this end, the authors combined a primary task (a number comparison task: classifying digits as smaller or larger than 5) with a Simon task. Control adjustments were observed in the form of typical sequential modulations of the Simon effect. In addition, the authors found sequential modulations of the numerical distance effect and an interaction of both effects. Results suggest that not only response conflict due to interference from task-irrelevant features but also processing demands of task-relevant features determine the level of control adjustment in the subsequent trial

Implicit task sets in task switching?

In 2 experiments, the authors compare stimulus-based versus task-rule-based task performance. Participants practiced 8 stimulus-response mappings either with or without knowledge about 2 underlying task sets. After practice, 2 transfer blocks with 8 new stimuli were presented. Results show that rule knowledge leads to significant switch and transfer costs, whereas without rule knowledge neither switch nor transfer costs occur. However, significant Task Type × Response Type interactions occurred in both conditions. In a second experiment including only the no rule condition, half of the stimulus-response mappings in the transfer blocks were incongruent to the underlying task rule. Slower response times for these incongruent stimuli as compared with congruent stimuli and the absence of switch costs suggest that participants acquired (presumably implicit) knowledge about 4 different stimulus-response categories

Individual differences in the context-dependent recruitment of cognitive control: Evidence from action versus state orientation

The ability to flexibly adapt to deviations from optimal performance is an important aspect of self-control. In the present study, the authors present first evidence that the personality trait action versus state orientation (Kuhl, 2000) modulates the ability of adaptive control adjustments in response to experienced conflicts. Sixty-two German individuals with extreme scores on the action-state dimension performed a response interference task, that is, 31 extreme action-oriented individuals (30 females; Mage  = 20.35 years) and 31 extreme state-oriented individuals (20 females; Mage  = 23.23 years), respectively. Action-oriented individuals displayed a stronger conflict adaptation effect as evidenced by a stronger reduction of interference on trials following conflict. These results were further corroborated by a correlational analysis including a sample of 105 participants: the higher the score on the action-state dimension, the lower the interference effect following conflict (i.e., stronger conflict adaptation). The results provide evidence that even low-level, bottom-up-driven processes of self-control such as conflict adaptation are systematically moderated by individual differences in control modes and provide insights into the cognitive mechanisms underlying action versus state orientation

Dopamine and cognitive control: The influence of spontaneous eyeblink rate, DRD4 exon III polymorphism and gender on flexibility in set-shifting

Converging evidence suggests a modulatory role of dopamine in cognitive control. We investigated the influence of two correlates of dopaminergic activity, the spontaneous eyeblink rate and the DRD4 exon III polymorphism, and the potential impact of gender on flexibility in an attentional set-shifting paradigm. The objective of the study was to confirm previous findings of an association between high eyeblink rates and increased cognitive flexibility. These findings were replicated in 87 healthy volunteers this time using a continuous variable for eyeblink rates instead of a dichotomized variable. The interaction between eyeblink rate and DRD4 found in the previous study was lower and failed significance. Analysis of the collapsed sample of n = 150 revealed a main effect of gender and an interaction of gender and eyeblink rate on cognitive control. The complete prediction model explained 26% of the total variance. These data suggest that (1) the eyeblink rate is a reliable predictor of dopamine-mediated flexibility of cognitive control and (2) it is useful to include gender as predictor in future studies of dopaminergic modulation of cognitive control

Genetic variation of serotonin function and cognitive control

Although it is widely accepted that serotonin plays a pivotal role in the modulation of anxiety- and depression-related personality traits as well as in the pathogenesis of anxiety disorders and depression, the role of serotonin in cognition is less clear. In the present study, we investigated the involvement of serotonin in cognitive behaviors by examining the impact of genetic variation in key regulators of serotonergic neurotransmission on behavioral measures in a cognitive control task. Eighty-five healthy participants performed a cued continuous performance task (the AX Continuous Performance Task [AXCPT]) and were genotyped for polymorphisms in the transcriptional control regions of the tryptophan hydroxylase 2 gene (TPH2 G-703T; rs4570625) and the serotonin transporter gene (5-HTTLPR). The core result was that individuals lacking the rare TPH2 T allele were not faster than T allele carriers, but committed fewer errors and were less variable in responding. These findings parallel those of a recent study where an enhancement of executive control in individuals without the rare TPH2 T/T genotype was observed. Together with recent evidence that individuals without the T allele exhibit higher scores in anxiety- and depression-related personality traits, our results underscore the role of the TPH2 G-703T polymorphism in the modulation of behavior and raise the intriguing possibility that genetic variants associated with higher negative emotionality may have beneficial effects on some cognitive functions

Dopamine and Cognitive Control: The influence of spontaneous eye-blink rate and dopamine gene polymorphisms on perseveration and distractibility

One fundamental problem of intelligent organisms pursuing goal-directed behavior is how to dynamically regulate the balance between maintenance and flexibility. The authors show that central dopaminergic activity, as indicated by spontaneous eyeblink rate and dopamine gene polymorphisms, plays an important role in the modulation of this balance. Seventy-two young adults were examined. Participants with high blink rates showed increased cognitive flexibility but decreased cognitive stability compared with participants with low blink rates. This pattern of results was even more pronounced for carriers of the DRD4 exon III 4/7 genotype, even though no main effects were found for DRD4 and COMT polymorphisms. Results converge with neuropsychological models that suggest a modulatory role of prefrontal dopaminergic activity for processes of cognitive control