Effects of cognitive load on neural and behavioral responses to smoking-cue distractors

Smoking cessation failures are frequently thought to reflect poor top-down regulatory control over behavior. Previous studies have suggested that smoking cues occupy limited working memory resources, an effect that may contribute to difficulty achieving abstinence. Few studies have evaluated the effects of cognitive load on the ability to actively maintain information in the face of distracting smoking cues. For the present study, we adapted an fMRI probed recall task under low and high cognitive load with three distractor conditions: control, neutral images, or smoking-related images. Consistent with a limited-resource model of cue reactivity, we predicted that the performance of daily smokers (n = 17) would be most impaired when high load was paired with smoking distractors. The results demonstrated a main effect of load, with decreased accuracy under high, as compared to low, cognitive load. Surprisingly, an interaction revealed that the effect of load was weakest in the smoking cue distractor condition. Along with this behavioral effect, we observed significantly greater activation of the right inferior frontal gyrus (rIFG) in the low-load condition than in the high-load condition for trials containing smoking cue distractors. Furthermore, load-related changes in rIFG activation partially mediated the effects of load on task accuracy in the smoking-cue distractor condition. These findings are discussed in the context of prevailing cognitive and cue reactivity theories. These results suggest that high cognitive load does not necessarily make smokers more susceptible to interference from smoking-related stimuli, and that elevated load may even have a buffering effect in the presence of smoking cues under certain conditions.     

The relationship between cognitive performance and electrophysiological indices of performance monitoring

Studies of electrophysiological indices of performance monitoring, such as the error-related negativity (ERN), posterror positivity (Pe), and N2 components of the event-related potential (ERP), suggest that increased ERN and Pe amplitudes and decreased N2 amplitudes are associated with better cognitive flexibility and cognitive control abilities; however, few studies have directly examined the relationship between cognitive performance and ERP indices of performance monitoring. We examined the neuropsychological profile of 89 healthy individuals who performed a modified flanker task. The neuropsychological domains tested included memory, verbal fluency, and attention/executive functioning. Pearson’s correlations and multiple regression analyses showed a significant relationship between measures of attention/executive functioning and ERN amplitude, even when negative affect, reaction time interference, and posterror slowing were controlled. N2 amplitude related only to posterror slowing. The amplitude of the Pe was not significantly related to any cognitive domains. These findings are consistent with recent work indicating that performance monitoring requires attention skills and cognitive flexibility. Implications for the conflict-monitoring and reinforcement-learning theories are discussed.     

Individual differences in working memory capacity predict action monitoring and the error-related negativity

Neuroscience suggests that the anterior cingulate cortex (ACC) is responsible for conflict monitoring and the detection of errors in cognitive tasks, thereby contributing to the implementation of attentional control. Though individual differences in frontally mediated goal maintenance have clearly been shown to influence outward behavior in interference-rich contexts, it is unclear whether corresponding differences exist in neural responses that arise out of the ACC. To investigate this possibility, we conducted an electrophysiological study using a variant of the Simon Task, recording event-related potentials (ERPs) in healthy normal individuals with varying working memory capacity (high vs. low spans; a behavioral proxy for variability in goal maintenance). Primary analyses focused on the magnitude of the error-related negativity (ERN), a response-locked ERP component associated with the commission of errors thought to arise because of action monitoring in the ACC. Our results revealed that frontally mediated working memory capacity may alter error monitoring by the ACC, with high spans showing a greater ERN than low spans. These individual differences were also observed in the posterror positivity, a response-locked ERP component associated with updating cognitive strategies, suggesting greater awareness of errors with increased working memory capacity. These results are interpreted within 2-process models of attentional control, suggesting individuals with greater working memory capacity may better maintain task goals by more strongly biasing neural activity in frontal-executive networks.     

Performance breakdown effects dissociate from error detection effects in typing

Mistakes in skilled performance are often observed to be slower than correct actions. This error slowing has been associated with cognitive control processes involved in performance monitoring and error detection. A limited literature on skilled actions, however, suggests that preerror actions may also be slower than accurate actions. This contrasts with findings from unskilled, discrete trial tasks, where preerror performance is usually faster than accurate performance. We tested 3 predictions about error-related behavioural changes in continuous typing performance. We asked participants to type 100 sentences without visual feedback. We found that (a) performance before errors was no different in speed than that before correct key-presses, (b) error and posterror key-presses were slower than matched correct key-presses, and (c) errors were preceded by greater variability in speed than were matched correct key-presses. Our results suggest that errors are preceded by a behavioural signature, which may indicate breakdown of fluid cognition, and that the effects of error detection on performance (error and posterror slowing) can be dissociated from breakdown effects (preerror increase in variability).     

Avoiding another mistake: Error and posterror neural activity associated with adaptive posterror behavior change

The magnitude of posterior medial frontal cortex (pMFC) activity during commission of an error has been shown to relate to adaptive posterror changes in response behavior on the trial immediately following. In the present article, we examined neural activity during and after error commission to identify its relationship to sustained posterror behavior changes that led to performance improvements several trials into the future. The standard task required participants to inhibit a prepotent motor response during infrequent lure trials, which were randomly interspersed among numerous go trials. Posterror behavior was manipulated by introducing a dynamic condition, in which an error on a lure trial ensured that the next lure would appear within two to seven go trials. Behavioral data indicated significantly higher levels of posterror slowing and accuracy during the dynamic condition, as well as fewer consecutive lure errors. Bilateral prefrontal cortex (PFC) and pMFC activity during the posterror period, but not during commission of the error itself, was associated with increased posterror slowing. Activity within two of these regions (right PFC and pMFC) also predicted success on the next lure trial. The findings support a relationship between pMFC/PFC activity and adaptive posterror behavior change, and the discrepancy between these findings and those of previous studies-in the present study, this relationship was detected during the posterror period rather than during commission of the error itself--may have resulted from the requirements of the present task. Implications of this discrepancy for the flexibility of cognitive control are discussed.     

Development of and change in cognitive control: A comparison of children, young adults, and older adults

Cognitive control involves adjustments in behavior to conflicting information, develops throughout childhood, and declines in aging. Accordingly, developmental and age-related changes in cognitive control and response-conflict detection were assessed in a response-compatibility task. We recorded performance measures, pre-response time (pre-RT) activity and medial frontal negativity (MFN)—sequentially occurring, putative event-related potential (ERP) indexes, respectively, of cognitive control and response-conflict detection. When response conflict reached the highest levels by requiring incompatible responses on posterror trials, children and older adults showed the greatest performance decrements. ERPs indicated that young adults implemented control (pre-RT) and detected the increased conflict (MFN) only when that conflict was at the highest levels, whereas children and older adults did so at lower levels (e.g., posterror, compatible responses). Consequently, the developmental and age-related performance decrements observed here may be due to the undifferentiated and inefficient manner in which children and older adults recruited the processes associated with both cognitive control and response-conflict detection.     

Resisting temptation of unhealthy food: interaction between temptation-elicited goal activation and self-control

Counteractive control theory suggests that the cognitive accessibility of a goal in response to a temptation cue predicts self-regulation of behaviour consistent with that goal. The current study provided a novel test of this effect in the eating domain, exploring the moderating role of trait self-control. A sample of 124 women (18–25 years) completed a lexical decision task to assess cognitive accessibility of the weight-management goal after food temptation priming. Eating self-regulation was operationalised as unhealthy snack food intake measured in a task disguised as a taste-test. Participants completed trait self-control and temptation experience intensity measures. Cognitive accessibility predicted lower food intake, but only among high self-control participants. The relationship was mediated by temptation experience intensity: participants with high cognitive accessibility felt less tempted, and subsequently ate less food. Results suggest that changing the processes underlying the temptation experience, rather than the cognitive accessibility of a goal may more effectively enhance self-regulation among low self-control individuals.     

A Cognitive Control Perspective of Self-Control Strength and Its Depletion

Self-control strength is a central construct to theories of willpower, optimal functioning, freedom from addiction, and abilities to override problematic social motives and behaviors (e.g., aggression). Understanding the processing basis of self-control strength, and more particularly its depletion, is thus of paramount importance to both basic and applied literatures. Self-control strength, the present review suggests, can be profitably viewed in cognitive control terms, particularly so in relation to operations of a brain-based cognitive control circuit involving the anterior cingulate cortex (linked to monitoring potential or actual unwanted outcomes) and the dorsolateral prefrontal cortex (linked to controlling potential or actual unwanted outcomes). Also, sufficient task motivation is important to operations of this circuit and depletion effects might be understood in terms of such depletion effects on task motivation. Multiple sources of evidence are marshaled in support of this cognitive control perspective of self-control strength. It is concluded that viewing self-control strength in cognitive control terms has considerable merit. Social, cognitive, personality, and clinical sources of data are integrated in the analysis.     

Self-control relies on glucose as a limited energy source: willpower is more than a metaphor

The present work suggests that self-control relies on glucose as a limited energy source. Laboratory tests of self-control (i.e., the Stroop task, thought suppression, emotion regulation, attention control) and of social behaviors (i.e., helping behavior, coping with thoughts of death, stifling prejudice during an interracial interaction) showed that (a) acts of self-control reduced blood glucose levels, (b) low levels of blood glucose after an initial self-control task predicted poor performance on a subsequent self-control task, and (c) initial acts of self-control impaired performance on subsequent self-control tasks, but consuming a glucose drink eliminated these impairments. Self-control requires a certain amount of glucose to operate unimpaired. A single act of self-control causes glucose to drop below optimal levels, thereby impairing subsequent attempts at self-control.     

Why do we slow down after an error? Mechanisms underlying the effects of posterror slowing

People often become slower in their performance after committing an error, which is usually explained by strategic control adjustments towards a more conservative response threshold. The present study tested an alternative hypothesis for explaining posterror slowing in terms of behavioural interferences resulting from error monitoring by manipulating stimulus contrast and categorization difficulty in a choice reaction time task. The response-stimulus interval (RSI) was either short or long, using a between-subject (Experiment 1) and a within-subject design (Experiment 2). Posterror slowing was larger and posterror accuracy lower in short than in long RSI situations. Effects of stimulus contrast disappeared in posterror trials when RSI was short. At long RSIs, stimulus contrast was additive with posterror slowing. The results support the idea that at least two mechanisms contribute to posterror slowing: a capacity-limited error-monitoring process with the strongest influence at short RSIs and a criterion adjustment mechanism at longer RSIs.     

Performance monitoring and the causal attribution of errors

The present study investigated the role of causal attribution for performance monitoring in the medial frontal cortex. To this end, we compared internally and externally-caused errors in a selective attention task with respect to error-related EEG activity and error-induced adjustments of speed and attentional selectivity. Both error types evoked early negativities and later positivities in the response-locked event-related potential. However, whereas internally-caused errors caused posterror slowing, externally-caused errors were followed by reduced attentional selectivity. Moreover, the amount of reduced attentional selectivity was related to the amplitude of the early negativity on externally-caused errors. This suggests that posterror adjustments are initiated on the basis of perceived causality and, thus, causal attribution of errors.     

False external feedback modulates posterror slowing and the f-P300: implications for theories of posterror adjustment

People tend to slow down after mistakes. This posterror slowing (PES) has commonly been explained by a change to a more conservative response threshold to avoid future errors. Alternatively, the attention-orienting account posits that all infrequent, surprising events (including errors) elicit an orienting response followed by a time-consuming process of task reorientation, explaining PES without increased response caution. In the present study, we employed both behavioral and electrophysiological measures to compare the predictions of these accounts using a flanker paradigm in which accurate or false external response feedback was provided. Participants demonstrated typical posterror adjustments, responding more slowly and accurately in posterror than in postcorrect trials. This finding provides initial evidence suggesting that posterror adjustments are motivated by the avoidance of subsequent mistakes. Most importantly, PES and an event-related potential relating to the attentional processing of feedback, the feedback-related P300 (f-P300), were modulated by feedback type. More specifically, the f-P300 was larger after false than after accurate feedback, suggesting that participants oriented their attention toward (i.e., were surprised by) inaccurate feedback signals. Interestingly, false feedback differentially modulated reaction times: Participants were slower after correct responses when feedback falsely informed of an error rather than confirmed the correct response. In contrast, faster responses were made after errors when feedback falsely indicated correct rather than incorrect performance. When these patterns of results are regarded together, they are best explained by theories of cognitive control in which posterror adjustments in choice reaction time tasks are assumed to reflect control processes leading to more conservative performance after error signals.     

Show or tell: Testimony is sufficient to induce the curse of knowledge in three- and four-year-olds

People often become slower in their performance after committing an error, which is usually explained by strategic control adjustments towards a more conservative response threshold. The present study tested an alternative hypothesis for explaining posterror slowing in terms of behavioural interferences resulting from error monitoring by manipulating stimulus contrast and categorization difficulty in a choice reaction time task. The response–stimulus interval (RSI) was either short or long, using a between-subject (Experiment 1) and a within-subject design (Experiment 2). Posterror slowing was larger and posterror accuracy lower in short than in long RSI situations. Effects of stimulus contrast disappeared in posterror trials when RSI was short. At long RSIs, stimulus contrast was additive with posterror slowing. The results support the idea that at least two mechanisms contribute to posterror slowing: a capacity-limited error-monitoring process with the strongest influence at short RSIs and a criterion adjustment mechanism at longer RSIs.     

Heart work after errors: Behavioral adjustment following error commission involves cardiac effort

Posterror slowing (PES) is the observation that people respond slower on trials subsequent to error commissions than on trials subsequent to correct responses. Different accounts have been proposed to explain PES. On the one hand, it has been suggested that PES arises from an adaptive increase in cognitive control following error commission, thereby making people more cautious after making an error. On the other hand, PES has been attributed to an orienting response, indicating that attention is shifted toward the error. In the present study we tested these accounts by investigating the effects of error commission in both flanker and switch tasks on two task-evoked cardiac measures: the interbeat interval—that is, the interval between two consecutive R peaks—and the RZ interval—that is, the interval between the R peak and the Z point—as measured using electro- and impedance cardiography, respectively. These measures allowed us to measure cardiac deceleration (autonomic orienting) and cardiac effort mobilization, respectively. Our results revealed a shorter RZ interval during posterror trials, indicating increased effort mobilization following errors. In addition, we replicated earlier studies that have shown cardiac slowing during error trials. However, multilevel analyses showed that only the posterror decrease in RZ interval predicted posterror reaction times, whereas there was no positive relationship between error-related cardiac deceleration and posterror reaction times. Our results suggest that PES is related to increased cardiac effort, supporting a cognitive-control account of PES.     

Preliminary evidence for reduced posterror reaction time slowing in hyperactive/inattentive preschool children

Background: Attention deficit/hyperactivity disorder (ADHD) has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in posterror slowing. Method: A computerized two-choice RT task was administered to an ethnically diverse sample of preschool-aged children classified as either “control” (n = 120) or “hyperactive/inattentive” (HI; n = 148) using parent- and teacher-rated ADHD symptoms. Analyses were conducted to determine whether HI preschoolers exhibit a deficit in this self-regulatory ability. Results: HI children exhibited reduced posterror slowing relative to controls on the trials selected for analysis. Supplementary analyses indicated that this may have been due to a reduced proportion of trials following errors on which HI children slowed rather than due to a reduction in the absolute magnitude of slowing on all trials following errors. Conclusions: High levels of ADHD symptoms in preschoolers may be associated with a deficit in error processing as indicated by posterror slowing. The results of supplementary analyses suggest that this deficit is perhaps more a result of failures to perceive errors than of difficulties with executive control.     

自我控制资源与认知资源相互影响的机制:整合模型

尽管有学者认为自我控制资源和认知资源应该是两种独立的资源,但近期的研究却表明两种资源是互相影响的.以往研究从执行控制的角度解释两种资源为什么相互影响,但却没有指出两种资源如何影响执行控制,以及缺乏考虑神经机制和自我控制资源调节变量在其中的作用.为更系统地解释两种资源相互影响的机制,作者提出了一个整合模型,该模型指出:(1)两种资源相互影响的主要原因是两者都受到执行控制和前额叶皮层的影响;(2)个体进行自我控制或认知加工会消耗能量,产生心理疲劳,降低执行任务的动机,表现为前额叶皮层激活水平下降;(3)前额叶皮层激活不足进一步限制了执行控制在随后的自我控制和认知加工任务中的作用,因而影响后续自我控制或认知加工任务的表现;(4)自我控制资源调节变量通过提高个体对疲劳的耐受性、补充能量和提高动机等方法,使前额叶皮层和执行控制在完成前一阶段任务后仍然能够正常发挥作用,从而维持个体在后续自我控制或认知加工任务上的表现.未来的研究可考察自我控制资源与其他认知加工的关系;用动态的认知神经研究方法,建立前额叶皮层激活水平在前后两阶段任务之间的中介作用模型,以及研究自我控制资源调节变量的神经机制.     

Personality predicts working-memory-related activation in the caudal anterior cingulate cortex

Behavioral studies suggest that two affective dimensions of personality are associated with working memory (WM) function. WM load is known to modulate neural activity in the caudal anterior cingulate cortex (ACC), a brain region critical for the cognitive control of behavior. On this basis, we hypothesized that neural activity in the caudal ACC during a WM task should be associated with personality: correlated negatively with behavioral approach sensitivity (BAS) and positively with behavioral inhibition sensitivity (BIS). Using functional magnetic resonance imaging, we measured brain activity in 14 participants performing a three-back WM task. Higher self-reported BAS predicted better WM performance (r = .27) and lower WM-related activation in the caudal ACC (r = -.84), suggesting personality differences in cognitive control. The data bolster approach-withdrawal (action control) theories of personality and suggest refinements to the dominant views of ACC and personality.     

Neural and behavioral measures of error-related cognitive control predict daily coping with stress

This study tested the hypothesis that individual differences in cognitive control can predict individual differences in emotion regulation. Participants completed color-word and emotional Stroop tasks while an electroencephalogram was recorded, and then they reported daily stressful events, affect, and coping for 14 days. Greater posterror slowing in the emotional Stroop task predicted greater negative affect in response to stressors and less use of task-focused coping as daily stressors increased. Participants whose neural activity best distinguished errors from correct responses tended to show less stress reactivity in daily self-reports. Finally, depression levels predicted daily affect and coping independent of cognitive control variables. The results offer qualified support for an integrated conception of cognitive and emotional self-regulation.     

Conflict monitoring and cognitive control

A neglected question regarding cognitive control is how control processes might detect situations calling for their involvement. The authors propose here that the demand for control may be evaluated in part by monitoring for conflicts in information processing. This hypothesis is supported by data concerning the anterior cingulate cortex, a brain area involved in cognitive control, which also appears to respond to the occurrence of conflict. The present article reports two computational modeling studies, serving to articulate the conflict monitoring hypothesis and examine its implications. The first study tests the sufficiency of the hypothesis to account for brain activation data, applying a measure of conflict to existing models of tasks shown to engage the anterior cingulate. The second study implements a feedback loop connecting conflict monitoring to cognitive control, using this to simulate a number of important behavioral phenomena.     

Age-related changes in neural mechanisms of prospective memory

The capability to remember and execute intentions in the future – termed prospective memory (PM) – may be of special significance for older adults to enable successful completion of important activities of daily living. Despite the importance of this cognitive function, mixed findings have been obtained regarding age-related decline in PM, and, currently, there is limited understanding of potential contributing mechanisms. In the current study, older (N=41) and younger adults (N=47) underwent task-functional MRI during performance of PM conditions that encouraged either spontaneous retrieval (Focal) or sustained attentional monitoring (Non-focal) to detect PM targets. Older adults exhibited a reduction in PM-related sustained activity within the anterior prefrontal cortex (aPFC) and associated dorsal frontoparietal cognitive control network, due to an increase in non-specific sustained activation in (no-PM) control blocks (i.e., an age-related compensatory shift). Transient PM-trial specific activity was observed in both age groups within a ventral parietal memory network that included the precuneus. However, within a left posterior inferior parietal node of this network, transient PM-related activity was selectively reduced in older adults during the non-focal condition. These age differences in sustained and transient brain activity statistically mediated age-related declines in PM performance, and were potentially linked via age-related changes in functional connectivity between the aPFC and precuneus. Together, they support an account consistent with the Dual Mechanisms of Control framework, in which age-related PM declines are due to neural mechanisms that support proactive cognitive control processes, such as sustained attentional monitoring, while leaving reactive control mechanisms relatively spared.