Local and global effects of motivation on cognitive control.

Motivation has been found to enhance cognitive control, but the mechanisms by which this occurs are still poorly understood. Cued motivational incentives (e.g., monetary rewards) can modulate cognitive processing locally-that is, on a trial-by-trial basis (incentive cue effect). Recently, motivational incentives have also been found to produce more global and tonic changes in performance, as evidenced by performance benefits on nonincentive trials occurring within incentive blocks (incentive context effect). In two experiments involving incentivized cued task switching, we provide systematic evidence that the two effects are dissociable. Through behavioral, diffusion-modeling, and individual-differences analyses, we found dissociations between local and global motivational effects that were linked to specific properties of the incentive signals (i.e., timing), while also ruling out alternative interpretations (e.g., practice and speed-accuracy trade-off effects). These results provide important clues regarding the neural mechanisms by which motivation exerts both global and local influences on cognitive control.

A characterization of individual differences in prospective memory monitoring using the Complex Ongoing Serial Task.

Prospective memory--remembering to retrieve and execute future goals--is essential to daily life. Prospective remembering is often achieved through effortful monitoring; however, potential individual differences in monitoring patterns have not been characterized. We propose 3 candidate models to characterize the individual differences present in prospective memory monitoring: attentional focus, secondary memory retrieval, and information thresholding. Two experiments using a novel paradigm, the Complex Ongoing Serial Task (COST), investigated the resource allocation patterns underlying individual differences in monitoring. Individuals exhibited differential resource allocation patterns, and the differences remained relatively stable across experimental sessions. Resource allocation patterns associated with information thresholding (high prospective memory, preserved ongoing task performance) and attentional focus (high prospective memory, inefficient ongoing task performance) were superior to secondary memory retrieval (low prospective memory, very inefficient ongoing task performance). Importantly, personality (openness, prevention focus) and cognitive (primary, working, and secondary memory) individual differences influenced monitoring patterns. This research represents the first explicit attempt to elucidate individual differences in prospective memory monitoring patterns.

Survival processing of faces.

The mnemonic benefit of rating words according to their relevance in a survival scenario is well documented (e.g., Nairne, Thompson, & Pandeirada, 2007). The present study examined whether the survival processing effect would extend to face stimuli. We tested this hypothesis in five experiments, using multiple survival and control scenarios, real and computer-generated face sets, within- and between-subjects designs, and several memory tests, as well as free recall of survival-relevant and survival-neutral attribute statements written about the person. Although the standard survival processing effect was obtained for survival-relevant and neutral attribute statements, the survival processing effect was not obtained for face memory across all experiments. These results identify an important boundary condition for survival processing benefits.

Motivated cognitive control: reward incentives modulate preparatory neural activity during task-switching.

It is increasingly appreciated that executive control processes need to be understood in terms of motivational as well as cognitive mechanisms. The current study examined the impact of performance-contingent reward incentives (monetary bonuses) on neural activity dynamics during cued task-switching performance. Behavioral measures indicated that performance was improved and task-switch costs selectively reduced on incentive trials. Trial-by-trial fluctuations in incentive value were associated with activation in reward-related brain regions (dopaminergic midbrain, paracingulate cortex) and also modulated the dynamics of switch-selective activation in the brain cognitive control network. Within lateral prefrontal cortex (PFC), both additive (inferior frontal junction) and interactive [dorsolateral PFC (DLPFC)] incentive effects were observed. In DLPFC, incentive modulation of activation predicted task-switching behavioral performance, but with hemispherically dissociable effects. Furthermore, in left DLPFC, incentive modulation specifically enhanced task-cue-related activation, and this activation in turn predicted that the trial would be subsequently rewarded (because of optimal performance). The results suggest that motivational incentives have a selective effect on brain regions that subserve cognitive control processes during task-switching and, moreover, that one mechanism of effect might be the enhancement of cue-related task preparation within left DLPFC.

Enhancement of cognitive control by approach and avoidance motivational states.

Affective variables have been shown to impact working memory and cognitive control. Theoretical arguments suggest that the functional impact of emotion on cognition might be mediated through shifting action dispositions related to changes in motivational orientation. The current study examined the effects of positive and negative affect on performance via direct manipulation of motivational state in tasks with high demands on cognitive control. Experiment 1 examined the effects of monetary reward on task-switching performance, while Experiment 2 examined the effects of both rewards and punishments on working memory, using primary (liquid) reinforcers. In both experiments, dissociable trial-by-trial and contextual (block-related) enhancements of cognitive control during task performance were observed in relationship to motivational incentive value. Performance enhancements were equivalent in the reward and punishment conditions, but were differentially impacted by individual difference measures of trait reward and punishment sensitivity. Together, the results suggest both common and specific mechanisms by which approach and avoidance motivational states influence cognitive control, via activation of reward and punishment processing systems.

Primary and secondary rewards differentially modulate neural activity dynamics during working memory.

BACKGROUND: Cognitive control and working memory processes have been found to be influenced by changes in motivational state. Nevertheless, the impact of different motivational variables on behavior and brain activity remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: The current study examined the impact of incentive category by varying on a within-subjects basis whether performance during a working memory task was reinforced with either secondary (monetary) or primary (liquid) rewards. The temporal dynamics of motivation-cognition interactions were investigated by employing an experimental design that enabled isolation of sustained and transient effects. Performance was dramatically and equivalently enhanced in each incentive condition, whereas neural activity dynamics differed between incentive categories. The monetary reward condition was associated with a tonic activation increase in primarily right-lateralized cognitive control regions including anterior prefrontal cortex (PFC), dorsolateral PFC, and parietal cortex. In the liquid condition, the identical regions instead showed a shift in transient activation from a reactive control pattern (primary probe-based activation) during no-incentive trials to proactive control (primary cue-based activation) during rewarded trials. Additionally, liquid-specific tonic activation increases were found in subcortical regions (amygdala, dorsal striatum, nucleus accumbens), indicating an anatomical double dissociation in the locus of sustained activation. CONCLUSIONS/SIGNIFICANCE: These different activation patterns suggest that primary and secondary rewards may produce similar behavioral changes through distinct neural mechanisms of reinforcement. Further, our results provide new evidence for the flexibility of cognitive control, in terms of the temporal dynamics of activation.