Effort Expenditure For Rewards Task Research Articles

Effort-cost decision-making associated with negative symptoms in schizophrenia and bipolar disorder

Motivational deficits and reduced goal-directed behavior for external rewards have long been considered an important features of negative symptoms in patients with schizophrenia (SCZ). Negative symptoms have also a high prevalence in bipolar disorder (BP). We used a transdiagnostic approach in order to examine association between negative symptoms and effort allocation for monetary rewards. 41 patients with SCZ and 34 patients with BP were enrolled in the study along with 41 healthy controls (HC). Effort-Expenditure for Rewards Task (EEfRT) was used to measure subjects' effort allocation for monetary rewards. Generalized estimating equation models were used to analyze EEfRT choice behavior. Negative symptoms were assessed using the Brief Negative Symptom Scale (BNSS). SCZ and BP groups expended lower effort to obtain a monetary rewards compared to HC. Severity of negative symptoms was negatively correlated with EEfRT performance in both diagnostic groups. Each diagnostic group showed lower effort allocation for monetary rewards compared to HC suggesting reduced motivation for monetary rewards. In addition, our results suggest that abnormal effort-based decision-making might be a transdiagnostic factor underlying negative symptoms.

Using Computational Phenotyping to Identify Divergent Strategies for Effort Allocation Across the Psychosis Spectrum.

Disturbances in effort-cost decision-making have been highlighted as a potential transdiagnostic process underpinning negative symptoms in individuals with schizophrenia. However, recent studies using computational phenotyping show that individuals employ a range of strategies to allocate effort, and use of different strategies is associated with unique clinical and cognitive characteristics. Building on prior work in schizophrenia, this study evaluated whether effort allocation strategies differed in individuals with distinct psychotic disorders. We applied computational modeling to effort-cost decision-making data obtained from individuals with psychotic disorders (n = 190) who performed the Effort Expenditure for Rewards Task. The sample included 91 individuals with schizophrenia/schizoaffective disorder, 90 individuals with psychotic bipolar disorder, and 52 controls. Different effort allocation strategies were observed both across and within different disorders. Relative to individuals with psychotic bipolar disorder, a greater proportion of individuals with schizophrenia/schizoaffective disorder did not use reward value or probability information to guide effort allocation. Furthermore, across disorders, different effort allocation strategies were associated with specific clinical and cognitive features. Those who did not use reward value or probability information to guide effort allocation had more severe positive and negative symptoms, and poorer cognitive and community functioning. In contrast, those who only used reward value information showed a trend toward more severe positive symptoms. These findings indicate that similar deficits in effort-cost decision-making may arise from different computational mechanisms across the psychosis spectrum.

Willingness to expend effort for rewards in individuals at clinical high-risk for psychosis: a relationship with the severity and stability of negative symptoms

To identify the deficit in willingness to expend effort and its association with negative symptoms in the high-risk for psychosis (CHR) group. The study included young men: 45 patients, who met CHR criteria and were treated for a depressive episode, and 15 controls. All subjects completed a modified version of the Effort Expenditure for Rewards Task (EEfRT). The CHR group was assessed with the SOPS, SANS and HDRS at the beginning and at the end of treatment. EEfRT was performed only at the end of treatment. The CHR group was significantly less likely to choose high effort tasks across reward probability and magnitude levels compared with the control group (all p<0.001). No significant correlations were found between the rate of selecting the high effort task and the negative syndrome domains of amotivation and diminished expression. The subgroups of CHR with stable and transient (i.e., with a reduction >50% during treatment) negative symptoms, which were identified by a cluster analysis, did not differ in the willingness to expend effort. The study confirmed a decrease in the willingness to expend effort in the CHR group; however, this deficit was only weakly correlated with negative symptoms and persisted after the symptoms reduction during treatment, which requires future studies to investigate mechanisms underlying impaired effort expenditure for rewards in CHR.

Effort-based decision-making as a determinant of supported employment outcomes in psychotic disorders

Schizophrenia is associated with a heavy economic burden in the United States that is partly due to the high rates of chronic unemployment. Individual Placement and Support (IPS) is an evidenced-based type of supported employment that can improve job obtainment and work outcomes in psychotic disorders. Outcomes vary widely and a persistent challenge for IPS is low levels of engagement in the initial job search phase. Past studies have focused on interview-based motivation deficits as a key determinant of poor treatment engagement and work outcomes in schizophrenia. New validated performance-based measures of motivation, including effort-based decision-making (EBDM) tasks, may explain supported employment outcomes and provide insights into individual differences in IPS outcomes. This study investigated the degree to which IPS engagement (i.e., number of sessions attended during the first four months of service delivery) was related to baseline interview-based motivation deficits and performance on three EBDM tasks – two tasks of physical effort and one of cognitive effort (i.e., Balloon Task, Effort Expenditure for Rewards Task, Deck Choice Effort Task) – in a sample (N = 47) of people with a psychotic disorder. Results indicated that the level of EBDM performance, specifically on the Balloon Task, predicted IPS engagement, accounting for an additional 17 % of the variance above and beyond interview-based motivation deficits (total R2 = 24 %). Overall, these findings suggest that addressing motivational deficits in effort-based decision-making may be beneficial to IPS engagement, which in turn may improve the trajectory of work outcomes.

Novel genome-wide associations for effort valuation and psychopathology in children and adults.

The Research Domain Criteria (RDoC) initiative was established by the US National Institute of Mental Health as a multilevel, disorder-agnostic framework for analysis of human psychopathology through designated domains and constructs, including the "Positive Valence Systems" domain focused on reward-related behavior. This study investigates the reward valuation subconstruct of "effort" and its association with genetic markers, functional neurobiological pathways, and polygenic risk scores for psychopathology in 1215 children aged 6-12 and their parents (n = 1044). All participants completed the effort expenditure for rewards task (EEfRT), which assesses "effort" according to two quantitative measures: hard-task choice and reward sensitivity. Genetic association analyses were undertaken in MAGMA, utilizing EEfRT outcome variables as genome-wide association studies phenotypes to compute SNP and gene-level associations. Genome-wide association analyses found two distinct genetic loci that were significantly associated with measures of reward sensitivity and a separate genetic locus associated with hard task choice. Gene-set enrichment analysis yielded significant associations between "effort" and multiple gene sets involved in reward processing-related pathways, including dopamine receptor signaling, limbic system and forebrain development, and biological response to cocaine. These results serve to establish "effort" as a relevant construct for understanding reward-related behavior at the genetic level and support the RDoC framework for assessing disorder-agnostic psychopathology.

Hormone sensitivity predicts the beneficial effects of transdermal estradiol on reward-seeking behaviors in perimenopausal women: A randomized controlled trial

Depression is highly prevalent during the menopause transition (perimenopause), and often presents with anxious and anhedonic features. This increased vulnerability for mood symptoms is likely driven in part by the dramatic hormonal changes that are characteristic of the menopause transition, as prior research has linked fluctuations in estradiol (E2) to emergence of depressed mood in at risk perimenopausal women. Transdermal estradiol (TE2) has been shown to reduce the severity of depression in clinically symptomatic women, particularly in those with recent stressful life events. This research extends prior work by examining the relation between E2 and reward seeking behaviors, a precise behavioral indicator of depression. Specifically, the current study utilizes a randomized, double blind, placebo-controlled design to investigate whether mood sensitivity to E2 flux (“hormone sensitivity”) predicts the beneficial effects of TE2 interventions on reward seeking behaviors in perimenopausal women, and whether recent stressful life events moderate any observed associations. MethodParticipants were 66 women who met standardized criteria for being early or late perimenopausal based on bleeding patterns. Participants were recruited from a community sample; therefore, mood symptoms varied across the continuum and the majority of participants did not meet diagnostic criteria for a depressive or anxiety disorder at the time of enrollment. Hormone sensitivity was quantified over an 8-week baseline period, using within-subjects correlations between repeated weekly measures of E2 serum concentrations and weekly anxiety (State Trait Anxiety Inventory) and anhedonia ratings (Snaith-Hamilton Pleasure Scale). Women were then randomized to receive 8 weeks of TE2 (0.1 mg) or transdermal placebo, and reward-seeking behaviors were assessed using the Effort-Expenditure for Rewards Task (EEfRT). ResultsParticipants who were randomized to receive transdermal estradiol and who demonstrated greater anxiety sensitivity to E2 fluctuations at baseline, demonstrated more reward seeking behaviors on the EEfRT task. Notably, the strength of the association between E2-anxiety sensitivity and post-randomization EEfRT for TE2 participants increased when women experienced more recent stressful life events and rated those events as more stressful. E2-anhedonia sensitivity was not associated with reward-seeking behaviors. ConclusionPerimenopausal women who are more sensitive to E2 fluctuations and experienced more recent life stress may experience a greater benefit of TE2 as evidenced by an increase in reward seeking behaviors.

Using latent profile analyses to classify subjects with anhedonia based on reward-related measures obtained in the FAST-MAS study

BackgroundGrowing evidence indicates that anhedonia is a multifaceted construct. This study examined the possibility of identifying subgroups of people with anhedonia using multiple reward-related measures to provide greater understanding the Research Domain Criteria's Positive Valence Systems Domain and pathways for developing treatments. MethodsLatent profile analysis of baseline data from a study that examined the effects of a novel kappa opioid receptor (KOR) antagonist drug on measures and biomarkers associated with anhedonia was used to identify subgroups. Measures included ventral striatal activation during the Monetary Incentive Delay task, response bias in the Probabilistic Reward Task, reward valuation scores from the Effort-Expenditure for Rewards Task, and scores from reward-related self-report measures. ResultsTwo subgroups were identified, which differed on self-report measures of reward. Participants in the subgroup reporting more anhedonia also reported more depression and had greater illness severity and functional impairments. Graphs of change with treatment showed a trend for the less severe subgroup to demonstrate higher response to KOR antagonist treatment on the neuroimaging measure, probabilistic reward task, and ratings of functioning; the subgroup with greater severity showed a trend for higher treatment response on reward-related self-report measures. LimitationsThe main limitations include the small sample size and exploratory nature of analyses. ConclusionsEvidence of possible dissociation between self-reported measures of anhedonia and other measures with respect to treatment response emerged. These results highlight the importance for future research to consider severity of self-reported reward-related deficits and how the relationship across measurement methods may vary with severity.

Hormone sensitivity and stressful life events predict the effects of transdermal estradiol on reward-seeking behaviors in perimenopausal women: A randomized controlled trial

Internalizing mood symptoms are highly prevalent during the menopause transition (perimenopause). Prior research demonstrates that perimenopausal women with greater estradiol (E2) variability are more likely to experience depression symptoms, especially following recent stressful life events (SLEs). Transdermal estradiol (TE2) has been shown to reduce the severity of depression in clinically symptomatic women, particularly in those with recent SLEs. This research extends prior work by examining the relation between E2 and precise behavioral indicators of depression, including reward-seeking behaviors. The current study utilizes a randomized, double blind, placebo-controlled design to investigate whether sensitivity to E2 flux predicts the effects of a TE2 intervention on reward-seeking behaviors in perimenopausal women, and whether SLE’s moderate any observed associations. Participants were 66 women who met standardized criteria for being early or late perimenopausal based on bleeding patterns. Hormone sensitivity was quantified over an 8-week baseline period, using within-subjects correlations between repeated weekly measures of E2 serum concentrations, anxiety symptoms, and anhedonia levels. Women were then randomized to receive 8 weeks of TE2 (0.1 mg) or transdermal placebo, and reward-seeking behaviors were assessed using the Effort-Expenditure for Rewards Task (EEfRT). There were no differences in EEfRT performance between randomized groups at baseline. Greater hormone sensitivity predicted more reward-seeking behaviors on the EEfRT task post-randomization, but only for participants randomized to TE2. Notably, the strength of this association increased when women experienced more SLEs. Perimenopausal women who are hormone sensitive with recent life stress may experience a greater benefit of TE2.

Modeling Effort-Based Decision Making: Individual Differences in Schizophrenia and Major Depressive Disorder

BackgroundA critical facet of motivation is effort-based decision making, which refers to the mental processes involved in deciding whether a potential reward is worth the effort. To advance understanding of how individuals with schizophrenia and major depressive disorder utilize cost-benefit information to guide choice behavior, this study aimed to characterize individual differences in the computations associated with effort-based decision making. MethodsOne hundred forty-five participants (51 with schizophrenia, 43 with depression, and 51 healthy control participants) completed the Effort Expenditure for Rewards Task, with mixed effects modeling conducted to estimate the predictors of decision making. These model-derived, subject-specific coefficients were then clustered using k-means to test for the presence of discrete transdiagnostic subgroups with different profiles of reward, probability, and cost information utilization during effort-based decision making. ResultsAn optimal 2-cluster solution was identified, with no significant differences in the distribution of diagnostic groups between clusters. Cluster 1 (n = 76) was characterized by overall lower information utilization during decision making than cluster 2 (n = 61). Participants in this low information utilization cluster were also significantly older and more cognitively impaired, and their utilization of reward, probability, and cost was significantly correlated with clinical amotivation, depressive symptoms, and cognitive functioning. ConclusionsOur findings revealed meaningful individual differences among participants with schizophrenia, depression, and healthy control participants in their utilization of cost-benefit information in the context of effortful decision making. These findings may provide insight into different processes associated with aberrant choice behavior and may potentially guide the identification of more individualized treatment targets for effort-based motivation deficits across disorders.

Effects of an experimentally induced inflammatory stimulus on motivational behavior in remitted depressed patients

BackgroundAcute inflammation is associated with sickness behavior characterized by reduced motivation for pleasurable activities in humans. The current study investigated the effect of an experimentally induced inflammatory stimulus on motivational reward in people who remitted from depression. MethodsThis randomized, double-blind crossover study involved 12 participants, 5 with remitted major depressive disorder (rMDD) and 7 healthy controls (HC), who received an injection of typhoid vaccine and placebo (or vice-versa) intramuscularly at least one week apart. At baseline and between 4 and 6 h post-injection on both days, participant mood was measured using the profile of mood states (POMS), and injection blood samples were collected for cytokines measurement. All participants completed the Effort Expenditure for Rewards Task (EEfRT), a behavioral paradigm measuring effort-based decision-making before and 4 h post-both injections. Generalized linear mixed modeling was used to evaluate group differences in choosing the hard over easy task to obtain a monetary reward. ResultsTyphoid vaccine increased IL-6 in all participants. On the EEfRT, a significant interaction between treatment condition (typhoid vs. placebo) and participant group (HC vs. rMDD) was found (p = .004). Analyses of simple effects within treatment conditions found that after placebo, HCs were more likely to choose the harder task than rMDD (OR = 3.21; p = .013). However, after the typhoid vaccine, no differences were found between rMDD and HC (p = .397). Analyses within participant groups found that the probability of choosing a hard task was higher after placebo for HC (OR = 1.37; p = .045), but not different within rMDD (p = .241). For HC at baseline, mood was significantly lower following injection with typhoid vaccine, relative to placebo (b = −1.03, p < .001); however, this effect should be considered coincidental, given that mood rating was taken prior to injection. For rMDD patients 4–6 h post-injection, mood was significantly lower following typhoid vaccine, relative to placebo (b = −0.981, p < .001 b = −0.77, p < .001). Finally, for HC receiving placebo, mood was significantly lower 4–6 h post-injection, relative to baseline (b = −1.76, p < .001). ConclusionsOur preliminary findings suggest persistent deficits in motivational reward processing function despite clinical improvement in remitted depressed patients.

Associations Between Cognitive and Physical Effort–Based Decision Making in People With Schizophrenia and Healthy Control Subjects

BackgroundEffort can take a variety of forms including physical (e.g., button pressing) and cognitive (e.g., working memory tasks). Few studies have examined whether individual differences in willingness to expend effort are similar or different across modalities. MethodsWe recruited 30 individuals with schizophrenia and 44 healthy control subjects to complete 2 effort-cost decision-making tasks: the Effort Expenditure for Rewards Task (physical effort) and the cognitive effort discounting task (cognitive effort). ResultsWillingness to expend cognitive and physical effort was positively associated for both individuals with schizophrenia and control subjects. Further, we found that individual differences in motivation and pleasure dimension of negative symptoms modulated the association between physical and cognitive effort. Specifically, participants with lower motivation and pleasure scores, irrespective of group status, showed stronger associations between task measures of cognitive and physical effort-cost decision making. ConclusionsThese results suggest a generalized deficit across effort modalities in individuals with schizophrenia. Further, reductions in motivation and pleasure may impact effort-cost decision making in a domain-general manner.

Effort-related decision making and cannabis use among college students.

Cannabis exerts an indirect effect on dopamine (DA) output in the mesolimbic projection, a circuit implicated in reward processing and effort expenditure, and thus may be associated with aberrant effort-based decision making. The "amotivation syndrome" hypothesis suggests that regular cannabis use results in impaired capacity for goal-directed behavior. However, investigations of this hypothesis have used divergent methodology and have not controlled for key confounding variables. The present study extends these findings by examining the relation between cannabis use and effort-related decision making in a sample of college students. Cannabis using (n = 25; 68% meeting criteria for Cannabis Use Disorder) and noncannabis using (n = 22) students completed the Effort Expenditure for Rewards Task (EEfRT). In generalized estimating equation models, reward magnitude, reward probability, and expected value predicted greater likelihood of selecting a high-effort trial. Furthermore, past-month cannabis days and cannabis use disorder symptoms predicted the likelihood of selecting a high-effort trial, such that greater levels of both cannabis use days and symptoms were associated with an increased likelihood after controlling for Attention Deficit/Hyperactivity Disorder (ADHD) symptoms, distress tolerance, income, and delay discounting. The results provide preliminary evidence suggesting that college students who use cannabis are more likely to expend effort to obtain reward, even after controlling for the magnitude of the reward and the probability of reward receipt. Thus, these results do not support the amotivational syndrome hypothesis. Future research with a larger sample is required to evaluate possible associations between cannabis use and patterns of real-world effortful behavior over time. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reduced sensitivity but intact motivation to monetary rewards and reversal learning in obesity

BackgroundObesity has been linked to altered reward processing but little is known about which components of reward processing including motivation, sensitivity and learning are impaired in obesity. We examined whether obesity compared to healthy weight controls is associated with differences in distinct subdomains of reward processing. To this end, we used two established paradigms, namely the Effort Expenditure for Rewards task (EEfRT) and the Probabilistic Reversal Learning Task (PRLT). Methods30 individuals with obesity (OBS) and 30 healthy weight control subjects (HC) were included in the study. Generalized estimating equation models were used to analyze EEfRT choice behavior. PRLT data was analyzed using both conventional behavioral variables of choices and computational models. ResultsOur findings from the different tasks speak in favor of a hyposensitivity to non-food rewards in obesity. OBS did not make fewer overall hard task selections compared to HC in the EEfRT suggesting generally intact non-food reward motivation. However, in highly rewarding trials (i.e.,trials with high reward magnitude and high reward probability),OBSmadefewer hard task selections compared to normal weight subjects suggesting decreased sensitivity to highly rewarding non-food reinforcers. Hyposensitivity to non-food rewards was also evident in OBS in the PRLT as evidenced by lower win-stay probability compared to HC. Our computational modelling analyses revealed decreased stochasticity but intact reward and punishment learning rates in OBS. ConclusionsOur findings provide evidence for intact reward motivation and learning in OBS but lower reward sensitivity which is linked to stochasticity of choices in a non-food context. These findings might provide further insight into the mechanism underlying dysfunctional choices in obesity.

The cost of giving: Examining the relationship between narcissistic, self-sacrificing, and empathetic traits on effortful versus effortless prosocial behavior

The purpose of this exploratory study was to examine whether specific personality traits differentially predict willingness to engage in altruistic prosocial behavior in the presence or absence of an effort cost. The study focused on narcissism, empathy, and self-sacrificing tendencies. Effortless prosocial behavior was measured using the Dictator Game, and effortful prosocial behavior was measured using the ‘pay-it-forward’ Effort Expenditure for Rewards Task (EEfRT). Narcissism was not associated with either effortful or effortless prosocial behavior. Empathy and self-sacrificing behavior influenced prosocial behavior differently depending on effort demands. High self-sacrificing tendencies predicted greater effortless prosocial behavior but less effortful prosocial behavior for an unknown recipient. In contrast, empathy was associated with increased effortful prosocial behavior.

Working through negativity: The influence of affective states on effort-based decision-making

Affective states can influence a range of cognitive outcomes, such as decision-making. However, the effect of valence and arousal state inductions on effort-based decision-making is unclear. This study employed a mixed design in which all participants viewed low and high-arousal images, and participants were randomized to either a neutral, positive, or negative valence image manipulation. Participants repeatedly viewed a valenced-image and then completed a trial of the Effort Expenditure for Rewards Task (EFfRT). Results of Experiment 1 (N = 197) demonstrated that a valence induction manipulation influenced effort-based decision-making. Individuals in the negative valence condition chose fewer high-effort, difficult options than those in the neutral and positive valence conditions. Experiment 2 (N = 226) sought to explore the interplay between affective states and motivation on effort-based decision-making. Results of Experiment 2 replicated the finding that negative affective states impair willingness to engage in effortful tasks and showed that negative affect moderated the relationship between intrinsic motivation and willingness to exert effort. Self-reported arousal ratings, but not valence ratings, were also predictive of effort-based decisions. This work demonstrates that affective states may alter the cost of effort expenditure for potential rewards. Negative valence weakens one's volition to exert physical effort to obtain a monetary reward.

Pharmacological investigations of effort-based decision-making in humans: Naltrexone and nicotine.

Many mental health disorders are characterized by an impaired ability, or willingness, to exert effort to obtain rewards. This impairment is modeled in effort-based decision tasks, and neuropharmacological studies implicate dopamine in this process. However, other transmitter systems such as opioidergic and cholinergic systems have received less attention. Here, in two separate studies we tested the acute effects of naltrexone and nicotine on effort-based decision-making in healthy adults. In Study 1, we compared naltrexone (50mg and 25mg) to placebo, and in Study 2, a pilot study, we compared nicotine (7mg) to placebo. In both studies, participants completed the Effort Expenditure for Rewards Task (EEfRT), which measured effort-based decision-making related to monetary rewards. Although subjects expended greater effort for larger reward magnitude and when there was a higher probability of receiving the reward, neither naltrexone nor nicotine affected willingness to exert effort for monetary rewards. Although the drugs produced significant and typical drug effects on measures of mood and behavior, they did not alter effort-based decision-making. This has implications both for the clinical use of these drugs, as well as for understanding the neuropharmacology of effort-related behavior.

Objective measures of reward sensitivity and motivation in people with high v. low anhedonia.

Anhedonia - a diminished interest or pleasure in activities - is a core self-reported symptom of depression which is poorly understood and often resistant to conventional antidepressants. This symptom may occur due to dysfunction in one or more sub-components of reward processing: motivation, consummatory experience and/or learning. However, the precise impairments remain elusive. Dissociating these components (ideally, using cross-species measures) and relating them to the subjective experience of anhedonia is critical as it may benefit fundamental biology research and novel drug development. Using a battery of behavioural tasks based on rodent assays, we examined reward motivation (Joystick-Operated Runway Task, JORT; and Effort-Expenditure for Rewards Task, EEfRT) and reward sensitivity (Sweet Taste Test) in a non-clinical population who scored high (N = 32) or low (N = 34) on an anhedonia questionnaire (Snaith-Hamilton Pleasure Scale). Compared to the low anhedonia group, the high anhedonia group displayed marginal impairments in effort-based decision-making (EEfRT) and reduced reward sensitivity (Sweet Taste Test). However, we found no evidence of a difference between groups in physical effort exerted for reward (JORT). Interestingly, whilst the EEfRT and Sweet Taste Test correlated with anhedonia measures, they did not correlate with each other. This poses the question of whether there are subgroups within anhedonia; however, further work is required to directly test this hypothesis. Our findings suggest that anhedonia is a heterogeneous symptom associated with impairments in reward sensitivity and effort-based decision-making.

Effort-based decision making and self-reported apathy in frequent cannabis users and healthy controls: A replication and extension

ABSTRACT Introduction Amotivational syndrome is a term used to refer to lack of motivation and passive personality related to chronic cannabis use. Given mixed findings, the current study aimed to replicate and extend previous research on frequent cannabis use, motivated behavior, and self-reported apathy. Method Cannabis users (on average, ≥3 days/week of cannabis use over the past year), and healthy controls (≤1 day/month of cannabis use over the past year) completed the Apathy Evaluation Scale (AES), and the Effort Expenditure for Rewards Task (EEfRT). Repeated measures analysis of covariance was used to 1) examine the effects of group, reward magnitude, probability, and their interaction on hard task selections on the EEfRT, and 2) examine between-group differences on the AES, controlling for alcohol use and depressive symptoms. Results There were significant main effects of reward magnitude, probability, and an interaction between reward magnitude and probability on hard task selection (p’s < 0.05). Specifically, as reward magnitude and probability of winning the reward increased, participants were more likely to select hard tasks on the EEfRT. Relative to healthy controls, cannabis users were significantly more likely to select hard tasks on the EEfRT (F(1,56) = 6.49, p = 0.014, ηp 2 = 0.10). When controlling for alcohol use and depressive symptoms, no significant group differences in self-reported apathy were present (p = 0.46). Conclusions Cannabis users exhibit a greater likelihood of exerting more effort for reward, suggesting enhanced motivation relative to healthy controls. Thus, the current results do not support amotivational syndrome in adult frequent cannabis users. Despite some harms of long-term cannabis use, amotivation may not be among them.

Examining the reliability and validity of two versions of the Effort-Expenditure for Rewards Task (EEfRT).

The Effort-Expenditure for Rewards Task (EEfRT) has gained validity evidence from several studies. However, various modifications have been applied to the original version, which have never been compared systematically. In Study 1, we tested 120 healthy participants to directly compare two versions of the EEfRT. In Study 2, we tested a larger sample of 394 healthy participants to further examine the original EEfRT. We replicated the split-half reliability of both task versions. However, self-reported personality traits (e.g., trait BAS) correlated with only some task performance parameters in Study 1, which did not replicate for the original EEfRT in Study 2. Our results indicate complex and sometimes inconsistent relations between different personality traits, task properties, and reward attributes.

Motor Preparation and Execution for Performance Difficulty: Centroparietal Beta Activation during the Effort Expenditure for Rewards Task as a Function of Motivation

Debate exists as to the effects of anxiety in performance-based studies. However, no studies have examined the influence of motivation both in preparation of a motor movement and during movement performance. The present study measured beta activation in preparation for and during execution of the effort expenditure for rewards task (EEfRT), a button-pressing task consisting of easy and hard trials. Results indicated that motor preparation (i.e., reduced beta activation) was greater in preparation for hard trials than for easy trials. Additionally, motor preparation decreased (i.e., beta activation increased) over the course of hard trial execution. These results suggest that motor preparation is enhanced prior to more challenging tasks but that motor preparation declines as participants become closer to completing their goal in each challenging trial. These results provide insight into how beta activation facilitates effort expenditure for motor tasks varying in difficulty and motivation. The impact of these results on models of anxiety and performance is discussed.