Reward circuitry activation reflects social preferences in the face of cognitive effort

Disentangling effort from probability of success: Temporal dynamics of frontal midline theta in effort-based reward processing

The ability to weigh a reward against the effort required to acquire it is critical for decision-making. However, extant experimental paradigms oftentimes confound increased effort demand with decreased reward probability, thereby obscuring neural correlates underlying these cognitive processes. To resolve this issue, we designed novel tasks that disentangled probability of success - and therefore reward probability - from effort demand. In Experiment 1, reward magnitude and effort demand were varied while reward probability was kept constant. In Experiment 2, effort demand and reward probability were varied while reward magnitude remained fixed. Electroencephalogram (EEG) data was recorded to explore how frontal midline theta (FMT; an electrophysiological index of mPFC function) and component P3 (an index of incentive salience) respond to effort demand, and reward magnitude and probability. We found no evidence that FMT tracked effort demands or net value during cue evaluation. At feedback, however, FMT power was enhanced for high compared to low effort trials, but not modulated by reward magnitude or probability. Conversely, P3 was sensitive to reward magnitude and probability at both cue and feedback phases and only integrated expended effort costs at feedback, such that P3 amplitudes continued to scale with reward magnitude and probability but were also increased for high compared to low effort reward feedback. These findings suggest that, when likelihood of success is equal, FMT power does not track net value of prospective effort-based rewards. Instead, expended cognitive effort potentiates FMT power and enhances the saliency of rewards at feedback. SIGNIFICANCE STATEMENT: The way the brain weighs rewards against the effort required to achieve them is critical for understanding motivational disorders. Current paradigms confound increased effort demand with decreased reward probability, making it difficult to disentangle neural activity associated with effort costs from those associated with reward likelihood. Here, we explored the temporal dynamics of effort-based reward (via frontal midline theta (FMT) and component P3) while participants underwent a novel paradigm that kept probability of reward constant between mental effort demand conditions. Our findings suggest that the FMT does not track net value and that expended effort enhances, instead of attenuates, the saliency of rewards.

Cognitive effort for self, strangers, and charities

Effort is aversive and often avoided, even when earning benefits for oneself. Yet, people sometimes work hard for others. How do people decide who is worth their effort? Prior work shows people avoid physical effort for strangers relative to themselves, but invest more physical effort for charity. Here, we find that people avoid cognitive effort for others relative to themselves, even when the cause is a personally meaningful charity. In two studies, participants repeatedly decided whether to invest cognitive effort to gain financial rewards for themselves and others. In Study 1, participants (N = 51; 150 choices) were less willing to invest cognitive effort for a charity than themselves. In Study 2, participants (N = 47; 225 choices) were more willing to work cognitively for a charity than an intragroup stranger, but again preferred cognitive exertion that benefited themselves. Computational modeling suggests that, unlike prior physical effort findings, cognitive effort discounted the subjective value of rewards linearly. Exploratory machine learning analyses suggest that people who represented others more similarly to themselves were more willing to invest effort on their behalf, opening up new avenues for future research.

Neural dynamics of effort-modulated reward processing

Previous studies have established that effort can either decrease reward value as a cost or increase reward value as an augmenter, which is referred to as the effort paradox. The present event-related potential study investigated the neural dynamics underlying the modulation of reward processing by effort expenditure. Thirty-two participants completed a modified monetary incentive delay task in a high-effort context and a low-effort context to earn monetary rewards while their EEG was recorded during effort anticipation, effort execution, and effort completion, respectively. Results revealed the multiphase nature of the effort-reward relationship, which unfolds over time. During effort anticipation, effort discounts reward value as reflected by a reduced contingent negative variation for high- versus low-effort trials. During effort exertion, the target-P3 reward effect was accrued by effort expenditure. Finally, effort also provides its own value following effort completion, as revealed by an enhanced stimulus-preceding negativity for high-effort relative to low-effort trials. These findings provide new insights into the relationship between effort expenditure and reward processing and are helpful to mitigate the effort paradox.

Predicting an Outcome Less Probable yet More Desirable than the Other

Extant research suggests that the desirability of an outcome influences the way an individual makes a prediction. The current research investigated how an outcome’s desirability influences the extent to which an individual evaluates its probability when making a prediction. Two studies were conducted using a single binary prediction based on the urn model. Individuals predicted which color—red or blue—a ball drawn from a bag would be, while being aware of the proportion of each color in the bag. The results of the first study indicated that individuals predicted the more probable outcome regardless of the probabilities of two outcomes. However, when the less probable outcome was more desirable, the proportion of predictions became significantly correlated and better calibrated to the actual probability. This result was interpreted as showing that, when motivated to predict the more desirable but less probable outcome, individuals evaluate its probability more effortfully. This interpretation was tested in the second study. When the probabiity- matching motivation was implemented, the proportion of individuals who predicted the less probable outcome increased significantly. However, when the less probable outcome was more desirable, the same motivation did not significantly increase the proportion of such individuals. Taken together, these results imply that individuals likely process the same probability informatio differently based on whether this information is useful for predicting a desirable outcome.

Underlying Mechanisms of Psychological Interventions in Magnetic Resonance Imaging and Image-Guided Radiology Procedures

Positive patient care and healthcare facility outcomes are associated with using various psychological interventions during magnetic resonance imaging and interventional radiology procedures. Interventions such as hypnosis, relaxation, guided imagery, and empathic communication can improve anxiety, pain, and hemodynamic stability during procedures, as well as improve claustrophobia and anxiety during magnetic resonance imaging. Little is understood as to the potential underlying mechanisms of how these interventions operate and contribute to positive outcomes. Thus, this article seeks to address that question by integrating autonomic nervous system functioning, neuropsychological concepts, and common factors theory of psychotherapy as potential underlying mechanisms. Opportunities for future directions in the field are also included.

Decomposing the effort paradox in reward processing: Time matters

Effort expenditure not only discounts reward value prospectively but also accrues reward value retrospectively. To decompose the effort paradox in reward processing, the current event-related potential study investigated the neural dynamics underlying effects of effort expenditure on subsequent reward processing. Participants exerted one of two levels of effort to obtain an opportunity of winning a high or low amount of monetary reward, and we focused on electrophysiological activity during the anticipatory and consummatory phases of reward processing. During the anticipatory phase, the stimulus-preceding negativity was enhanced when potential high rewards were anticipated, but this reward effect disappeared following high-effort expenditure. During the consummatory phase, feedback-related ERPs were increased for high relative to low rewards, and this reward effect was enlarged following effort expenditure during the early stage (200-300 ms) as indexed by the reward positivity but not the late stage (400-600 ms) as indexed by the P3. Our findings provide a strong support for the psychological contrast theory and indicate that time matters in decomposing the effort paradox for reward processing such that effort expenditure reduces reward sensitivity during the anticipatory phase but enhances reward sensitivity during the consummatory phase.

Predicting an Outcome Less Probable yet More Desirable than the Other

Extant research suggests that the desirability of an outcome influences the way an individual makes a prediction. The current research investigated how an outcome's desirability influences the extent to which an individual evaluates its probability when making a prediction. Two studies were conducted using a single binary prediction based on the urn model. Individuals predicted which color-red or blue-a ball drawn from a bag would be, while being aware of the proportion of each color in the bag. The results of the first study indicated that individuals predicted the more probable outcome regardless of the probabilities of two outcomes. However, when the less probable outcome was more desirable, the proportion of predictions became significantly correlated and better calibrated to the actual probability. This result was interpreted as showing that, when motivated to predict the more desirable but less probable outcome, individuals evaluate its probability more effortfully. This interpretation was tested in the second study. When the probabiity- matching motivation was implemented, the proportion of individuals who predicted the less probable outcome increased significantly. However, when the less probable outcome was more desirable, the same motivation did not significantly increase the proportion of such individuals. Taken together, these results imply that individuals likely process the same probability informatio differently based on whether this information is useful for predicting a desirable outcome.