Where is (im)balance? Necessity and construction of evaluated cut‐off points for effort‐reward imbalance and overcommitment

The use of cut‐off values is common in research on the effort‐reward imbalance (ERI) model. They are often used to identify health risk situations or behaviour at work, although little is known about their diagnostic properties. The aim of the study was to investigate empirically cut‐off points for the effort‐reward ratio and the overcommitment (OC) scale. The study was based on a sample of 302 teachers. According to the International Classification of Mental and Behavioural Disorders‐10 (ICD‐10), 115 subjects suffered from a mood disorder. The control group consisted of 187 matched healthy subjects. Receiver‐operating characteristic analyses were conducted using the ERI ratio and OC as diagnostic variables. A mood disorder served as gold standard reference test. Results demonstrated the ability of the effort‐reward ratio and OC to discriminate between diseased and healthy individuals. However, a comparison of the areas under the curve revealed a significantly higher diagnostic power for the effort‐reward ratio. According to the Youden index, optimal cut‐off points were ERI>0.715 and OC>16. Furthermore, sensitivity and specificity for different cut‐off values are presented. Results point to shortcomings in the ERI literature using established approaches to define cut‐off points. Validating cut‐off values is of particular importance in order to ensure valid results in ERI research.     

Children's Sensitivity to Cost and Reward in Decision Making across Distinct Domains of Probability,Effort, and Delay

Many behavioral paradigms used to study individuals' decision‐making tendencies do not capture the decision components that contribute to behavioral outcomes, such as differentiating decisions driven toward a reward from decisions driven away from a cost. This study tested a novel decision‐making task in a sample of 403 children (age 9 years) enrolled in an ongoing longitudinal study. The task consisted of three blocks representing distinct cost domains (delay, probability, and effort), wherein children were presented with a deck of cards, each of which consisted of a reward and a cost. Children elected whether to accept or skip the card at each trial. Reward–cost pairs were selected by using an adaptive algorithm to strategically sample the decision space in the fewest number of trials. Using person‐specific regression models, decision preferences were quantified for each cost domain with respect to general tolerance (intercept), as well as parameters estimating the effect of incremental increases in reward or cost on the probability of accepting a card. Results support the relative independence of decision‐making tendencies across cost domains, with moderate correlations observed between tolerance for delay and effort. Specific decision parameters showed unique associations with cognitive and behavioral measures including executive function, academic motivation, anxiety, and hyperactivity. Evidence indicates that sensitivity to reward is an important factor in incentivizing decisions to work harder or wait longer. Dissociating the relative contributions of reward and cost sensitivity in multiple domains may facilitate the identification of heterogeneity in suboptimal decision making. Copyright © 2017 John Wiley & Sons, Ltd.     

Response rate correlates with indifference points in a delay‐discounting procedure

To study how effort affects reward value, we replicated Fortes, Vasconcelos and Machado's (2015) study using an adjusting‐delay task. Nine pigeons chose between a standard alternative that gave access to 4 s of food, after a 10 s delay, and an adjusting‐delay alternative that gave access to 12 s of food after a delay that changed dynamically with the pigeons' choices, decreasing when they preferred the standard alternative, and increasing when they preferred the adjusting alternative. The delay value at which preference stabilized defined the indifference point, a measure of reward value. To manipulate effort across phases, we varied the response rate required during the delay of the standard alternative. Results showed that a) the indifference point increased in the higher‐response‐rate phases, suggesting that reward value decreased with effort, and b) in the higher‐response‐rate phases, response rate in the standard alternative was linearly related to the indifference point. We advance several conceptions of how effort may change perceived delay or amount and thereby affect reward value.     

Reformative self‐control and discounting of reward value by delay or effort1

Abstract: The relation between reformative self‐control and discounting of reward value by delay or effort was examined. Thirty‐two Japanese undergraduates were selected based on their scores on a standardized pencil and paper test of self‐control, the Redressive–Reformative Self‐Control Scale ( Sugiwaka, 1995 ). The subjects indicated their preference (i) between a hypothetical 100 000 yen reward available with various delays and a certain reward of variable amount available immediately; or (ii) between a hypothetical 100 000 yen reward available with various efforts and a certain reward of variable amount available without effort. The discounting of delayed reward value was described well by a hyperbolic function proposed by Mazur (1987 ). The slopes of the delayed discounting curves were steeper for subjects who scored low on the Reformative Self‐Control Scale, which is a measure of reformative self‐control and a subscale of the Redressive–Reformative Self‐Control Scale. The discounting by effort was also described well by the hyperbolic function. The slopes of the effortful discounting curves did not correlate to those of the delayed discounting curves. The slopes were not systematically different across the groups of subjects with different scores on the reformative self‐control scale.     

Effort‐reward‐imbalance,overcommitment and self‐reported health: Is it the interaction that matters?

In recent years, the effort‐reward‐imbalance (ERI) model has become widely used as a framework for examining job characteristics and employee's health. The present study tested the predictive validity of the ERI model's components ‐ ERI, over‐commitment (OC) and their interaction ‐ on the basis of self‐reported health outcomes. In a cross‐sectional study, data were obtained from 1,587 employees working in the aircraft manufacturing industry in southern Germany. Results suggested that all components of the ERI model (effort‐reward‐ratio, effort, reward and over‐commitment) are associated with health‐related quality of life, vital exhaustion, depression and quality of sleep. The separate variables effort and reward explained more of the observed variance than the effort‐reward ratio. No interaction between ERI and OC in predicting measurements of self‐reported health could be found. The findings suggest (1) that the ERI ratio does not provide more information than the separate use of the variables effort and reward, and (2) that there are main effects of ERI and OC but no interaction effect on employees' health. Implications for theory and applied research are discussed.     

Physical and cognitive effort discounting of hypothetical monetary rewards

Effort discounting refers to the decrease in the subjective value of a reward as the effort required to obtain the reward increases. The main aims of this study were to ascertain whether the amount of the reward affects the steepness of the effort discounting process for hypothetical monetary rewards, to identify whether this steepness depends on the type of effort that is required, and to determine whether the steepness of different types of effort covary at the individual level. Two types of effort were studied under hypothetical choice situations: physical effort and cognitive effort. Both physical and cognitive effort discounting were well described by the hyperbolic model. Large rewards were discounted less steeply than small rewards for both types of effort. This finding agrees with the results of prior studies which have found that larger rewards have greater motivational power. In addition, the steepness of physical effort discounting was positively correlated with the steepness of cognitive effort discounting, which suggests that the effort discounting process is a trait‐like characteristic within an individual.     

Eye blink rate predicts reward decisions in adolescents

The ventral striatum displays hyper‐responsiveness to reward in adolescents relative to other age groups, and animal research on the developmental trajectory of the dopaminergic system suggests that dopamine may underlie adolescent sensitivity to reward. However, practical limitations prevent the direct measurement of dopamine in healthy adolescents. Eye blink rate (EBR) shows promise as a proxy measure of striatal dopamine D2 receptor function. We investigated developmental differences in the relationship between EBR and reward‐seeking behavior on a risky decision‐making task. Increasing EBR was associated with greater reward maximization on the task for adolescent but not adult participants. Furthermore, adolescents demonstrated greater sensitivity to reward value than adults, as evinced by shifts in decision patterns based on increasing potential reward. These findings suggest that previously observed adolescent behavioral and neural hypersensitivity to reward may in fact be due to greater dopamine receptor activity, as represented by the relationship of blink rate and reward‐seeking behavior. They also demonstrate the feasibility and utility of using EBR as a proxy for dopamine in healthy youth in whom direct measurements of dopamine are prohibitively invasive.     

Reinforcement sensitivity of sex offenders and non‐offenders: An experimental and psychometric study of reinforcement sensitivity theory

This study tested predictions of Gray's Reinforcement Sensitivity Theory (RST) in subgroups of sex offenders and male non‐offenders using an experimental choice task consisting of a reward and a non‐reward phase. In addition, RST‐related psychometric measures were used. Both experimental and psychometric data were of interest to determine whether sex offenders could be reliably differentiated from non‐offenders. Paraphilic (N=50) and impulse control‐disordered (N=48) sex offenders showed greater sensitivity to continuous reward than male non‐offenders (N=51). Impulse control‐disordered sex offenders showed less behavioural adaptation under non‐reward than both paraphilic sex offenders and male non‐offenders. In addition, reward sensitivity, rash‐spontaneous impulsivity, and anxiety measures discriminated sex offenders from male non‐offenders. The results suggest that reinforcement sensitivity is a promising personality trait for differentiating subgroups of sex offenders from non‐offenders. The experimental and psychometric results illustrate that predictive accuracy in forensic settings could be improved by combining several types of data.     

Different ways to get the job done: comparing the effects of intellectual stimulation and contingent reward leadership on task‐related outcomes

Two experiments were conducted to compare the effects of intellectual stimulation and contingent reward leadership on performance, task enjoyment, and extra effort. Participants (N = 78 and N = 158) viewed one of three videos and performed an in‐basket exercise. Several interesting differences emerged. Across both studies, participants in the control and contingent reward leadership conditions generated more ideas than their counterparts in the intellectual stimulation condition. Additionally, participants reported more willingness to exert extra effort when the leader was either intellectually stimulating or emphasized contingent reward leadership, as compared to the control condition. Finally, while task enjoyment was higher in the contingent reward leadership condition than in the control condition in Study 1, no significant differences emerged among conditions for enjoyment in Study 2.     

努力：成本还是奖赏?

努力(Effort)与奖赏系统关系密切。当前关于努力在奖赏加工中的作用存在两个截然相反的观点：努力是一种成本还是一种奖赏?理论模型包括：其一, 努力是一种成本, 会降低奖赏的价值, 相应的理论解释包括内部成本模型、机会成本模型及信号模型等; 其二, 努力能够提升奖赏的价值, 相应的理论解释包括认知失调和努力的合理化模型、习得性勤奋理论及认知需求理论等。这两种观点均得到了来自于动物学、行为学、电生理学以及神经影像学等证据的支持。未来研究需要对努力准确定义, 从时间进程角度对努力的理论进行整合, 进一步考察努力的相关影响因素。     

Dysfunctional Eating in an Australian Community Sample: The Role of Emotion Regulation,Impulsivity, and Reward and Punishment Sensitivity

This study aimed to examine the role of emotion regulation and reinforcement sensitivity in dysfunctional eating behaviours. Two hundred twenty‐eight adults from the Australian community completed self‐report inventories assessing the variables. Dysfunctional restrained eaters differed from those who did not engage in restrained eating in terms of their emotion regulation, impulsivity, and sensitivity to reward. Difficulties in emotion regulation, low impulsivity, and sensitivity to reward predicted engagement in restrained eating. Emotional eaters significantly differed from those who did not engage in dysfunctional levels of emotional eating in terms of their emotion regulation, impulsivity, and sensitivity towards reward, and difficulties in emotion regulation predicted emotional eating. Finally, dysfunctional external eaters differed from non‐dysfunctional external eaters in terms of their emotion regulation, impulsivity, sensitivity towards reward, as well as sensitivity towards punishment, and difficulties with emotion regulation and sensitivity towards reward predicted external eating. These findings highlight the importance of the inclusion of emotional functioning in models of development and maintenance of eating disorders, and support the potential implementation of treatment interventions that address emotion regulation and include strategies to cope with impulsivity and reinforcement sensitivities.     

Effects of Frustration Increase and Decrease on Percentage of Short Interresponse Times

The finding by H. L. Armus (1986) that short (less than 1 s) interresponse times (IRTs) occur with greater frequency at higher levels of required lever-pressing effort was investigated. It has been hypothesized that greater percentages of short IRTs at higher effort requirements are an expression of frustration (S. Boyer & R. Carroll, 1980); in the present study, between-groups manipulations of effort and reward combinations were made in an attempt to increase and decrease relative frustration and thereby increase and decrease percentages of short IRTs. The subjects were 17 experimentally naive, male Long-Evans rats. Manipulation of effort requirements and reward magnitudes yielded both an increase and a decrease in percentage of short IRTs. The rats switched from low effort and high reward to high effort and low reward demonstrated the greatest increase in percentage of short IRTs, whereas the rats switched from low effort and low reward to high effort and high reward demonstrated a decrease in short IRTs.     

Effort discounting in human nucleus accumbens

A great deal of behavioral and economic research suggests that the value attached to a reward stands in inverse relation to the amount of effort required to obtain it, a principle known as effort discounting. In the present article, we present the first direct evidence for a neural analogue of effort discounting. We used fMRI to measure neural responses to monetary rewards in the human nucleus accumbens (NAcc), a structure previously demonstrated to encode reference-dependent reward information. The magnitude of accumbens activation was found to vary with both reward outcome and the degree of mental effort demanded to obtain individual rewards. For a fixed level of reward, the NAcc was less strongly activated following a high-demand for effort than following a low demand. The magnitude of this effect was noted to correlate with preceding activation in the dorsal anterior cingulate cortex, a region that has been proposed to monitor information-processing demands and to mediate in the subjective experience of effort.     

Rats place greater value on rewards produced by high effort: An animal analogue of the “effort justification” effect

The effort justification phenomenon, in which greater value is given to rewards that require more effort to obtain, is frequently explained in terms of cognitive dissonance (Festinger & Carlsmith, 1959). Here, we employed a novel combination of operant and lick analysis techniques to show that rats place more value on a sucrose reward when it follows high effort than when the same reward follows low effort. This is the first demonstration of a direct analogue of the effort justification phenomenon in nonhuman animals. As the behavior of rats is normally considered in terms of relatively simple mechanisms, the current results question the need for complex cognitive accounts for the effort justification phenomenon (in rats or humans). As an alternative, we examine the possibility that high effort produces an aversive state that enhances reward value by a process of contrast.     

Does effort influence inequity aversion in cotton-top tamarins (Saguinus oedipus)?

The human sense of fairness entails sensitivity not just to equality, the equal division of resources, but also to merit, the relationship between an individual’s share of resources and how hard they worked for their share. Recent evidence suggests that our sensitivity to equality has deep phylogenetic roots: several nonhuman animal species show an aversion to unequal reward distributions. However, the extent to which nonhuman animals share sensitivity to merit remains poorly understood, largely because previous studies have failed to properly manipulate work effort in inequity aversion tasks. Here, we tested whether cotton-top tamarins (Saguinus oedipus) would exhibit a differential response to inequity when acquiring rewards was either (1) effortful or (2) effortless. Subjects engaged in a pulling task in which they had an opportunity to deliver a disadvantageously unequal distribution of food to themselves and a partner (one piece for self, four pieces for partner). We made delivery effortful by adding a weight to the pulling handle. Critically, effort was calibrated to each individual. Results show that individuals varied markedly in their response to effort, highlighting the importance of manipulating work effort at the individual level. Overall, subjects showed little aversion to inequity. However, subjects were slightly less likely to accept inequity when doing so was effortful, although this effect was pronounced in only one individual. Our findings suggest a new method for capturing individual variation in effort and for studying the roots of the concept of merit in nonhuman animals.     

I'm worth more than you! Effects of reward interdependence on performance,cohesion, emotion and effort during team competition

ObjectivesTo examine the effects of reward structures on the performance of a motor task. To evaluate the effects of reward interdependence on performance, cohesion, emotion, and effort during intergroup (team) competition.DesignAn experimental design was used to compare the effects of reward interdependence (no, low, high) on performance of a strength and endurance task.MethodParticipants (N = 111) performed a 3-min handgrip task as a member of a team of four under three reward interdependence conditions (no; low, with an even split of prize money; high, with an uneven split of prize money) in head-to-head competitions against another team. Task performance was assessed using the cumulative force production total. Task-related cohesion, enjoyment, anxiety and effort were measured using self-report scales.ResultsPerformance was better with rewards than no reward, and better with high than low reward interdependence. Team cohesion was highest with low reward interdependence. Effort was greater with rewards than no reward. Anxiety and enjoyment did not vary among the reward conditions. Mediation analyses indicated that increased cohesion mediated improvements in performance from no reward to low reward interdependence conditions, and increased effort mediated improvements in performance from no reward to both low and high reward interdependence conditions.ConclusionPerformance of a simple physical task in team competition was facilitated by rewards, with optimal performance associated with unequal rewards (i.e., performance-related pay). The benefits of performing with rewards compared to no rewards were explained by increased cohesion and effort. Social interdependence theory can help explain performance of simple motor tasks during team-based competitions. The findings have implications for the pay structures adopted by sports teams.     

Impact of the effort–reward imbalance model on intent to leave among Belgian health care workers: A prospective study

The aim of this study was to analyse the impact of the effort–reward imbalance (ERI) model on intent to leave the current organization (ITL organization) and intent to leave the nursing profession (ITL profession) in a prospective way. A total of 1,531 health care workers who remained in their job filled in a self‐administered questionnaire at baseline and 1 year later. ERI was measured at baseline by a 23‐item questionnaire. Multivariate logistic regression analyses were performed. Within a population with low intent to leave at baseline, we found that an imbalance between high efforts and low rewards (extrinsic hypothesis) increased the risk of high ITL organization (OR 4.98; 95% CI 2.07–11.97) and high ITL profession (OR 1.84; 95% CI 1.03–3.30), 1 year later. A high level of overcommitment (OC; intrinsic hypothesis) was not predictive for both intent to leave outcome variables, neither was the interaction between high efforts/low rewards and a high level of OC (interaction hypothesis). Our results showed that a perceived effort‐reward imbalance (ERI) at work is a significant predictor of intent to leave among health care workers. This contribution concludes with some directions aimed at boosting nurses' retention and recommendations for future research.     

Investigating the influence of an effort–reward interaction on cognitive fatigue in individuals with multiple sclerosis

This study examined whether an alteration in the effort–reward relationship, a theoretical framework based on cognitive neuroscience, could explain cognitive fatigue. Forty persons with MS and 40 healthy age- and education-matched cognitively healthy controls (HC) participated in a computerized switching task with orthogonal high- and low-demand (effort) and reward manipulations. We used the Visual Analog Scale of Fatigue (VAS-F) to assess subjective state fatigue before and after each condition during the task. We used mixed-effects models to estimate the association and interaction between effort and reward and their relationship to subjective fatigue and task performance. We found the high-demand condition was associated with increased VAS-F scores (p < .001), longer response times (RT) (p < .001) and lower accuracy (p < .001). The high-reward condition was associated with faster RT (p = .006) and higher accuracy (p = .03). There was no interaction effect between effort and reward on VAS-F scores or performance. Participants with MS reported higher VAS-F scores (p = .02). Across all conditions, participants with MS were slower (p < .001) and slower as a function of condition demand compared with HC (p < .001). This behavioural study did not find evidence that an effort–reward interaction is associated with cognitive fatigue. However, our findings support the role of effort in subjective cognitive fatigue and both effort and reward on task performance. In future studies, more salient reward manipulations could be necessary to identify effort–reward interactions on subjective cognitive fatigue.     

Monetary reward increases attentional effort in the flanker task

An important question is whether monetary reward can increase attentional effort in order to improve performance. Up to now, evidence for a positive answer is weak. Therefore, in the present study, the flanker task was used to examine this question further. Participants had to respond sooner than a certain deadline in a flanker task. One group of participants received a performance-contingent monetary reward, whereas the other group earned a fixed amount of money. As a result, monetary reward significantly improved performance in comparison with the control group. The analysis of speed-accuracy trade-off functions revealed that monetary reward increased attentional effort, leading to an enhanced quality of stimulus coding. Little evidence was found that reward also improved selective spatial attention.