Approach‐motivated pregoal states enhance the reward positivity

Past work has demonstrated that the reward positivity (RewP) indexes a performance‐monitoring system sensitive to positive outcomes. However, studies have not investigated how approach‐motivated states occurring in goal pursuit influence performance monitoring. Using a modified monetary incentive delay task, participants played a reaction time game evoking approach‐motivated pregoal (reward trials) or neutral (no‐reward trials) states. Then, they received trial feedback resulting in monetary gain or no gain. Results revealed that the RewP was larger to win feedback on reward trials than win or no‐win feedback after neutral trials. P3 amplitudes were larger to infrequent feedback than frequent feedback, regardless of trial type or outcome. Furthermore, faster reaction times on reward trials related to larger RewP amplitudes after approach‐motivated pregoal states. Approach‐motivated pregoal states enhance RewP amplitudes for both successful and unsuccessful goal outcomes. Enhanced performance, as measured by faster reaction times, in approach‐motivated pregoal states relates to enhanced performance monitoring.     

Hypomania and depression associated with distinct neural activity for immediate and future rewards

Bipolar spectrum and unipolar depressive disorders have been associated with distinct and opposite profiles of reward‐related neural activity. These opposite profiles may reflect a differential preexisting vulnerability for both types of disorders. In support, recent ERP studies find that, following reward feedback, a larger reward positivity (RewP) is associated with greater vulnerability for bipolar spectrum disorders, whereas a smaller RewP is associated with greater vulnerability for depression. However, prior studies have investigated only immediate rewards and have not examined dimensions of both bipolar disorder and unipolar depression within the same sample. The present study is the first to investigate feedback‐related ERP correlates of proneness to hypomania and unipolar depressive tendencies within the same sample and to expand our scope to include future rewards. Participants completed a modified time estimation task where the same monetary reward was available immediately or at one of five different future dates. Results revealed proneness to hypomania and unipolar depressive tendencies were related to an elevated and blunted RewP, respectively, but only following immediate rewards (i.e., today). Following rewards in the distant future (e.g., 8 months), proneness to hypomania and depressive tendencies were associated with elevated and blunted amplitudes for the P3, respectively, a subsequent ERP component reflecting motivational salience during extended feedback processing. Furthermore, these opposing profiles were independent of, and significantly different from, one another. These results suggest that feedback‐related ERPs following immediate and future rewards are candidate biomarkers that can physiologically separate vulnerability for bipolar spectrum from unipolar depressive disorders.     

The reward positivity: From basic research on reward to a biomarker for depression

Feedback indicating monetary loss elicits an apparent negative deflection in the event‐related potential (ERP) that has been referred to as the feedback error‐related negativity, medial frontal negativity, feedback‐related negativity, and feedback negativity—all conceptualizations that suggest a negative ERP component that is greater for loss than gain. In the current paper, I review a programmatic line of research indicating that this apparent negativity actually reflects a reward‐related positivity (RewP) that is absent or suppressed following nonreward. I situate the RewP within a broader nomological network of reward processing and individual differences in sensitivity to rewards. Further, I review work linking reductions in the RewP to increased depressive symptoms and risk for depression. Finally, I discuss future directions for research on the RewP.     

Blunted neural response to rewards prospectively predicts depression in adolescent girls

The prevalence of depression increases substantially during adolescence. Several predictors of major depressive disorder have been established, but their predictive power is limited. In the current study, the feedback negativity (FN), an event‐related potential component elicited by feedback indicating monetary gain versus loss, was recorded in 68 never‐depressed adolescent girls. Over the following 2 years, 24% of participants developed a major depressive episode (MDE); illness onset was predicted by blunted FN at initial evaluation. Lower FN amplitude predicted more depressive symptoms during the follow‐up period, even after controlling for neuroticism and depressive symptoms at baseline. This is the first prospective study to demonstrate a link between a neural measure of reward sensitivity and the first onset of an MDE. The current results suggest that low reward sensitivity may be an important factor in the development of depression.     

Blunted neural response to gains versus losses associated with both risk‐prone and risk‐averse behavior in a clinically diverse sample

Reduced responsiveness to reward has been associated with both risk‐prone and risk‐averse behavior, common features of externalizing and internalizing psychopathology, respectively. Thus, evidence has suggested a potential quadratic relationship (i.e., inverted U) between reward sensitivity and risk‐taking propensity. Blunted response to reward compared to loss may therefore demonstrate transdiagnostic utility as it relates to different patterns of maladaptive risk behavior. The current study sought to disentangle the relationship between risk and reward in a clinically diverse sample. In a sample of 210 adults (aged 18–30), the RewP (an ERP indexing differentiation between rewards and losses) was measured during a monetary guessing game, and risk‐taking propensity was measured with a behavioral task (i.e., BART) that simulates real‐world risk taking. Participants also completed clinical assessments to assess for lifetime psychopathology. Results indicated that there was no linear association between the RewP and risk‐taking propensity; however, there was a significant quadratic relationship. Thus, a reduced sensitivity to reward receipt was associated with both risk‐prone and risk‐averse behavior. There was also a significant quadratic relationship between the RewP and money won during the BART, indicating that being too risk prone or risk averse is disadvantageous and leads to missed reward. Overall, these findings suggested that blunted neural differentiation between gains and losses may contribute to deficits in effectively weighing reward and loss and result in maladaptive risk‐taking behavior. These findings support continued examination of reward dysfunction dimensionally in order to better characterize behavioral profiles implicated in clinical phenotypes.     

Impulsivity-related personality traits and adolescent alcohol use: A meta-analytic review

Heightened impulsivity has been identified as a risk marker for excessive and problematic alcohol use, particularly during adolescence when impulsive behaviour is elevated and alcohol use is often initiated. Recent advances in personality theory indicate that impulsivity comprises several discrete traits which may influence alcohol use through different pathways. This review used meta-analysis to assess the degree to which the impulsivity-related traits of lack of premeditation, lack of perseverance, sensation seeking, negative urgency, positive urgency, and reward sensitivity are associated with alcohol consumption and problematic alcohol use in adolescent samples. All traits were positively associated with both alcohol outcomes. Sensation seeking and positive urgency showed the largest associations with alcohol consumption. Positive and negative urgency showed the largest associations with problematic alcohol use, although this was limited to older adolescent samples. A number of demographic and methodological variables were assessed as potential moderators of these associations. Results indicate that excessive alcohol consumption during adolescence may be driven in part by the desire to seek novel and exciting experiences. Problematic use, specifically amongst older adolescents, may be a consequence of a tendency to act rashly when in a heightened positive or negative mood.     

Win,lose, or draw: Examining salience,reward memory,and depression with the reward positivity

The reward positivity (RewP) is a putative biomarker of depression. Careful control of stimulus properties and manipulation of both stimulus valence and salience could facilitate interpretation of the RewP. RewP interpretation could further be improved by investigating functional outcomes of a blunted RewP in depression, such as reduced memory for rewarding outcomes. This study sought to advance RewP interpretation first by advancing task design through use of neutral (i.e., draw) control trials and counterbalanced feedback stimuli. Second, we examined the RewP’s association with memory and the impact of depression. Undergraduates completed self-report measures of depression and anhedonia prior to a modified doors task in which words were displayed in colored fonts that indicated win, loss, or draw feedback. Memory of the feedback associated with each word (i.e., source memory) was tested. Results showed that RewP response to wins was more positive than to losses, which was more positive than to draws. The RewP was not associated with depression or anhedonia. The low depression group showed a source memory advantage for win words, but the high depression group did not. Source memory showed small relations to the RewP, but these did not survive Bonferroni correction. Results suggest the RewP is sensitive to salience and highlight challenges in detecting an association between the RewP and depression in modified doors tasks. Findings indicate that depression is related to dysfunctional source memory for reward but not loss and that future research should probe the possible associations between the RewP and memory in depression.     

Relation of depression symptoms to sustained reward and loss sensitivity

Depression is characterized by altered sensitivity to rewards, with recent evidence suggesting that the ability to sustain responses to rewards across long experimental tasks is diminished. Most work on sustained reward responsiveness has taken a categorical approach and focused on major depressive disorder. However, impairments in reward sensitivity are also found at lower levels of symptom severity and may be relevant for understanding basic mechanisms linking reward processing abnormalities to depression. The current study took a dimensional approach to examine the relation between depression symptoms and sustained reward responsiveness by examining how early neural responses to rewards and losses change over a short time course (i.e., during the experiment). In a sample of 45 unselected undergraduates, changes in the amplitude of the reward positivity (RewP) and feedback negativity (FN) were examined over the course of a simple gambling task using multilevel modeling. Amplitude of the RewP was sustained and amplitude of the FN increased during the task. Unlike prior work focused on clinical populations, depression symptoms in this unselected sample were associated with enhanced RewP and FN responding over the course of the task. Results echo prior work that underscores the importance of examining changes in response to reward across trials and further suggests that sustained responses to both rewards and losses vary in relation to symptom level.     

Facets of impulsivity are differentially linked to insomnia: evidence from an exploratory study

This study investigated the association between insomnia and four facets of impulsivity as distinguished by Whiteside and Lynam (2001): urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. A sample of 233 university students completed the UPPS Impulsive Behavior Scale, the Insomnia Severity Index, and a short questionnaire on sleep-related mentation. Correlational analyses revealed that urgency was related to insomnia severity and insomnia-related impairments in daytime functioning, and that lack of perseverance was related to insomnia-related impairments in daytime functioning. Follow-up analyses showed that the frequency of disturbing thoughts and visions during the pre-sleep period partially mediated the relation between urgency and sleep-initiation problems, and that the frequency of disturbing dreams and nightmares partially mediated the relation between urgency and sleep-maintenance problems. These findings suggest that the facets of impulsivity are differentially linked to insomnia and that urgency is associated with sleep-interfering nighttime mentation.     

Neural responses to social and monetary reward in early adolescence and emerging adulthood

Reward processing is often considered to be a monolithic construct, with different incentive types eliciting equivalent neural and behavioral responses. The majority of the literature on reward processing has used monetary incentives to elicit reward‐related activity, yet social incentives may be particularly important due to their powerful ability to shape behavior. Findings from studies comparing social and monetary rewards have identified both overlapping and distinct responses. In order to explore whether reward processing is domain general or category specific (i.e., the same or different across reward types), the present study recorded ERPs from early adolescents (ages 12–13) and emerging adults (ages 18–25) while they completed social and monetary reward tasks. Temporospatial principal components analysis revealed morphologically similar reward positivities (RewPs) in the social and monetary reward tasks in each age group. In early adolescents, no significant difference was found between the magnitude of the RewP to social and monetary rewards. In emerging adults, however, the RewP to monetary rewards was significantly larger than the RewP to social rewards. Additionally, responses to feedback between the two tasks were not significantly correlated in either age group. These results suggest that both domain‐general and category‐specific processes underlie neural responses to rewards and that the relative incentive value of different types of rewards may change across development. Findings from this study have important implications for understanding the role that neural response to rewards plays in the development of psychopathology during adolescence.     

Toward a neurobehavioral trait conceptualization of depression proneness

The etiology of major depressive disorder is heterogeneous, and differing pathways leading to the development of depression are proposed to account for alternative variants of depressive illness and their distinct comorbidity patterns. The present study was undertaken as a step toward developing a model for conceptualizing and quantifying dispositional proneness to depression, marked by reduced neural sensitivity to rewarding events and more persistent occurrence of depressive symptomatology. Using data for college and community adult participants (N = 201), we sought to quantify variations in depression proneness by combining symptom indicators of persistent depressive conditions (dysthymic disorder, depressive personality) with a brain potential response that has been shown to index sensitivity to pleasurable events—the reward positivity (RewP; Proudfit, 2015). We first extended prior work on the RewP and depression by showing that the magnitude of RewP covaried negatively with symptoms of persistent depressive conditions (dysthymia, depressive personality) but not with current levels of depression. Persistent depressive symptoms and the RewP were then combined to form a composite neuroclinical index of depression proneness. Compared to persistent depressive symptoms alone, this composite dimensional index showed improved specificity of relations with diagnostic criterion measures, that is, similar‐level associations with other indicators of depression proneness but significantly lower associations with fear disorder symptomatology. These findings provide evidence that a dimension of depression proneness can be quantified effectively by combining psychological indicators of persistent depression with a neurophysiological index of a core depression‐related process (i.e., reward sensitivity).     

Anger is associated with reward‐related electrocortical activity: Evidence from the reward positivity

Previous research indicates that the reward positivity (RewP), an electrophysiological correlate of sensitivity and biases towards rewarding stimuli, is modulated by affective and motivational variables. Studies have provided evidence that states and traits associated with negative affect and reduced approach motivation are correlated with smaller RewP amplitudes. However, the possible confound of affective valence and motivational direction was not addressed in these studies. In the present study, we examined if anger, an emotion associated with negative affect and increased approach motivation, would affect RewP amplitude. We also investigated if RewP amplitude was related to the motivational properties of reward stimuli. One hundred male participants completed two emotion inductions intended to elicit feelings of either neutrality or anger. Each was followed by a simple gambling task, in which correct choices were followed by images of women in lingerie or swimwear. Although the RewP was elicited following each induction, there was no difference in amplitude between the neutral and anger induction. However, RewP amplitude was positively correlated with how much participants liked the reward stimuli, and this correlation was statistically larger following the anger induction. These results support a motivational interpretation for the differences in RewP amplitude reported in previous studies, suggesting that motivational direction and intensity, rather than affective valence, underlie differences in RewP amplitude. Moreover, the RewP appears to be affected by interactions between motivational state and the motivational value of reward stimuli.     

Perceived control increases the reward positivity and stimulus preceding negativity

The reward positivity (RewP) and the stimulus preceding negativity (SPN), two ERPs associated with reward delivery and reward anticipation, are modulated by motivational intensity. Motivational intensity is the effort organisms would make to exert behaviors, and it varies with the difficulty of exerting that behavior. If a task is perceived as impossible, which means that one does not have control over own outcomes, motivational intensity is low. In the current study, we tested the prediction that perceiving control over one's outcomes increases both the RewP to feedback and the SPN prior to feedback compared to perceiving no control. We also examined whether P300 and LPP amplitudes to reward and nonreward images were similarly modulated. Twenty‐five female participants completed a gambling task in which correct choices were followed by pictures of attractive men and incorrect choices were followed by pictures of rocks. To manipulate perceived control, participants were told that, in one block of trials, they could learn a mouse‐click rule in order to see only pictures of men (high perceived control condition), while in the other block, the pictures would appear randomly (low perceived control condition). However, in both conditions, feedback appeared randomly. Although the RewP was elicited in both blocks, the RewP and SPN were higher in the high perceived control condition (i.e., when participants thought that they could influence their outcomes). Perceived control did not modulate the P300 and LPP to pictures. The results suggest that approach motivation and its intensity modulate the processing of performance feedback.     

Acute stress impairs reward positivity effect in probabilistic learning

Decision making based on feedback learning requires a series of cognitive processes, including estimating the probability of particular outcomes and modulating expectations between expected versus actual outcomes. It has been suggested that stress affects decision making and subsequent processing of feedback valence and magnitude. However, less is known about the effect of acute stress on reward expectancy. In the current study, participants performed a probabilistic learning task, in which they learned an association between response and feedback within different reward expectancy trials (30% and 70%) under the conditions of stress (threat of shock) and safety (no shock). We recorded event-related potentials (ERPs) to measure the reward positivity (RewP) which reflects reward prediction error signals during feedback processing. Behavioral data indicated that participants performed better in the 70% reward trials than in the 30% reward trials. However, no significant difference was observed between stress and safe conditions. Importantly, ERP results indicated that unexpected feedback elicited larger RewP than did expected feedback and this expectancy effect of RewP was reduced in the stress relative to safe condition. Moreover, the correlations between RewP and choice accuracy (70% − 30% reward condition) in the safe and stress conditions were in a similar pattern; yet, only in the stress condition the correlation reached significantly. This may indicate that blunted RewP was associated with impaired performance at an individual level. Our study provides ERP evidence that acute stress affects brain responses to reward prediction error processing, which may explain various abnormal learning behaviors associated with stress-related disorders.     

Reliability of the electrocortical response to gains and losses in the doors task

The ability to differentiate between rewards and losses is critical for motivated action, and aberrant reward and loss processing has been associated with psychopathology. The reward positivity (RewP) and feedback negativity (FN) are ERPs elicited by monetary gains and losses, respectively, and are promising individual difference measures. However, few studies have reported on the psychometric properties of the RewP and FN—crucial characteristics necessary for valid individual difference measures. The current study examined the internal consistency and 1‐week test‐retest reliability of the RewP and FN as elicited by the doors task among 59 young adults. The RewP, FN, and their difference score (ΔRewP) all showed significant correlations between Time 1 and Time 2. The RewP and FN also achieved acceptable internal consistency at both time points within 20 trials using both Cronbach's α and a generalizability theory‐derived dependability measure. Internal consistency for ΔRewP was notably weaker at both time points, which is expected from two highly intercorrelated constituent scores. In conclusion, the RewP and FN have strong psychometric properties in a healthy adult sample. Future research is needed to assess the psychometric properties of these ERPs in different age cohorts and in clinical populations.     

Preparing for saliencies: Emotional expectations under probabilistically and aversively salient situations

In humans, the expectation process in decision making has not been as thoroughly investigated as the evaluation process. The present study focused on the interaction between probabilistic saliency and motivational saliency during expectation and evaluation periods using stimulus‐preceding negativity (SPN) and reward positivity (RewP). Twenty healthy participants performed a modified monetary‐incentive delay task under reward‐approach and punishment‐avoidance conditions. Each condition was characterized by the likely outcome (reward only, punishment only) to manipulate motivational saliency. The task difficulty was regulated to control for probabilistic saliency, and the error trial was set as a probabilistically salient event (75% correct, 25% error). The results demonstrated that there was a larger SPN in the 25%‐error trial than the 75%‐correct trial and that it was left hemisphere predominant. Furthermore, there was an interaction between probabilistic and motivational saliency such that the SPN in the error trial was larger in the punishment‐avoidance than in the reward‐approach condition at Fz and at the right hemisphere. In contrast, RewP was only significantly different from zero in the 75%‐correct trial in the reward‐approach condition. These results confirm that the SPN increases with probabilistic saliency and that probabilistically salient events may intervene in the motivational saliency of the outcome; furthermore, that RewP reflects the weighted positive value of the outcome for reward but not the weighted negative value of the outcome for punishment. We discuss the interaction between probabilistic saliency and motivational saliency on SPN and its left hemisphere predominance based on the functions of the insular cortex.     

Electrophysiological measures of conflict and reward processing are associated with decisions to engage in physical effort

Anterior cingulate cortex (ACC), a key brain region involved in cognitive control and decision making, is suggested to mediate effort- and value-based decision making, but the specific role of ACC in this process remains debated. Here we used frontal midline theta (FMT) and the reward positivity (RewP) to examine ACC function in a value-based decision making task requiring physical effort. We investigated whether (1) FMT power is sensitive to the difficulty of the decision or to selecting effortful actions, and (2) RewP is sensitive to the subjective value of reward outcomes as a function of effort investment. On each trial, participants chose to execute a low-effort or a high-effort behavior (that required squeezing a hand-dynamometer) to obtain smaller or larger rewards, respectively, while their brainwaves were recorded. We replicated prior findings that tonic FMT increased over the course of the hour-long task, which suggests increased application of control in the face of growing fatigue. RewP amplitude also increased following execution of high-effort compared to low-effort behavior, consistent with increased valuation of reward outcomes by ACC. Although neither phasic nor tonic FMT were associated with decision difficulty or effort selection per se, an exploratory analysis revealed that the interaction of phasic FMT and expected value of choice predicted effort choice. This interaction suggests that phasic FMT increases specifically under situations of decision difficulty when participants ultimately select a high-effort choice. These results point to a unique role for ACC in motivating and persisting at effortful behavior when decision conflict is high.     

Dissociable effects of reward magnitude on fronto-medial theta and FRN during performance monitoring

Reward processing is influenced by reward magnitude, as previous EEG studies showed changes in amplitude of the feedback-related negativity (FRN) and reward positivity (RewP), or power of fronto-medial theta (FMθ). However, it remains unclear whether these changes are driven by increased reward sensitivity, altered reward predictions, enhanced cognitive control, or a combination of these effects. To address this question, we asked 36 participants to perform a simple gambling task where feedback valence (reward vs. no-reward), its magnitude (small vs. large reward), and expectancy (expected vs. unexpected) were manipulated in a factorial design, while 64-channel EEG was recorded concurrently. We performed standard ERP analyses (FRN and RewP) as well as time-frequency decompositions (FMθ) of feedback-locked EEG data. Subjective reports showed that large rewards were more liked and expected than small ones. At the EEG level, increasing magnitude led to a larger RewP irrespective of expectancy, whereas the FRN was not influenced by this manipulation. In comparison, FMθ power was overall increased when reward magnitude was large, except if it was unexpected. These results show dissociable effects of reward magnitude on the RewP and FMθ power. Further, they suggest, that although large reward magnitude boosts reward processing (RewP), it can nonetheless undermine the need for enhanced cognitive control (FMθ) in case reward is unexpected. We discuss these new results in terms of optimistic bias or positive mood resulting from an increased reward magnitude.     

Teasing apart the anticipatory and consummatory processing of monetary incentives: An event‐related potential study of reward dynamics

The monetary incentive delay (MID) task has been widely used in fMRI studies to investigate the neural networks involved in anticipatory and consummatory reward processing. Previous efforts to adapt the MID task for use with ERPs, however, have had limited success. Here, we sought to further decompose reward dynamics using a comprehensive set of anticipatory (cue‐N2, cue‐P3, contingent negative variation [CNV]) and consummatory ERPs (feedback negativity [FN], feedback P3 [fb‐P3]). ERP data was recorded during adapted versions of the MID task across two experiments. Unlike previous studies, monetary incentive cues modulated the cue‐N2, cue‐P3, and CNV; however, cue‐related ERPs and the CNV were uncorrelated with one another, indicating distinct anticipatory subprocesses. With regard to consummatory processing, FN amplitude primarily tracked outcome valence (reward vs. nonreward), whereas fb‐P3 amplitude primarily tracked outcome salience (uncertain vs. certain). Independent modulation of the cue‐P3 and fb‐P3 was observed, indicating that these two P3 responses may uniquely capture the allocation of attention during anticipatory and consummatory reward processing, respectively. Overall, across two samples, consistent evidence of both anticipatory and consummatory ERP activity was observed on an adapted version of the MID paradigm, demonstrating for the first time how these ERP components may be integrated with one another to more fully characterize the time course of reward processing. This ERP‐MID paradigm is well suited to parsing reward dynamics, and can be applied to both healthy and clinical populations.     

Temporal prediction modulates the evaluative processing of “good” action feedback: An electrophysiological study

The present study aimed to investigate whether or not the evaluative processing of action feedback can be modulated by temporal prediction. For this purpose, we examined the effects of the predictability of the timing of action feedback on an ERP effect that indexed the evaluative processing of action feedback, that is, an ERP effect that has been interpreted as a feedback‐related negativity (FRN) elicited by “bad” action feedback or a reward positivity (RewP) elicited by “good” action feedback. In two types of experimental blocks, the participants performed a gambling task in which they chose one of two cards and received an action feedback that indicated monetary gain or loss. In fixed blocks, the time interval between the participant's choice and the onset of the action feedback was fixed at 0, 500, or 1,000 ms in separate blocks; thus, the timing of action feedback was predictable. In mixed blocks, the time interval was randomly chosen from the same three intervals with equal probability; thus, the timing was less predictable. The results showed that the FRN/RewP was smaller in mixed than fixed blocks for the 0‐ms interval trial, whereas there was no difference between the two block types for the 500‐ms and 1,000‐ms interval trials. Interestingly, the smaller FRN/RewP was due to the modulation of gain ERPs rather than loss ERPs. These results suggest that temporal prediction can modulate the evaluative processing of action feedback, and particularly good feedback, such as that which indicates monetary gain.