Appetitive Motivation in Depressive Anhedonia: Effects of Piece-Rate Cash Rewards on Cardiac and Behavioral Outcomes

Action-orientation shields against primed cognitive conflict effects on effort-related cardiac response

This article presents a quasi-experiment (N = 79 university students) testing whether individual differences in action-state orientation moderate primed cognitive conflict's effects on sympathetically mediated cardiac response during task performance reflecting effort. Action control theory posits that action-oriented individuals are less receptive to distracting affective stimuli during goal pursuit than state-oriented individuals because action-orientation is related to higher volitional skills. Therefore, we expected that action-oriented individuals should be shielded against conflict primes' effect on effort-related responses in the cardiovascular system. By contrast, state-oriented individuals should be more sensitive to irrelevant negative affective stimulation and therefore mobilize higher resources under such conditions. Responses of the cardiac pre-ejection period (PEP) during a moderately difficult short-term memory task corroborated these predictions. The present findings provide the first evidence that individual differences in action-state orientation indeed moderate previously demonstrated cognitive conflict priming effects on effort-related cardiac response and extend recent findings on action shielding.

Economic Choice and Heart Rate Fractal Scaling Indicate That Cognitive Effort Is Reduced by Depression and Boosted by Sad Mood

BACKGROUND

People with depression typically exhibit diminished cognitive control. Control is subjectively costly, prompting speculation that control deficits reflect reduced cognitive effort. Evidence that people with depression exert less cognitive effort is mixed, however, and motivation may depend on state affect.

METHODS

We used a cognitive effort discounting task to measure propensity to expend cognitive effort and fractal structure in the temporal dynamics of interbeat intervals to assess on-task effort exertion for 49 healthy control subjects, 36 people with current depression, and 67 people with remitted depression.

RESULTS

People with depression discounted more steeply, indicating that they were less willing to exert cognitive effort than people with remitted depression and never-depressed control subjects. Also, steeper discounting predicted worse functioning in daily life. Surprisingly, a sad mood induction selectively boosted motivation among participants with depression, erasing differences between them and control subjects. During task performance, depressed participants with the lowest cognitive motivation showed blunted autonomic reactivity as a function of load.

CONCLUSIONS

Discounting patterns supported the hypothesis that people with current depression would be less willing to exert cognitive effort, and steeper discounting predicted lower global functioning in daily life. Heart rate fractal scaling proved to be a highly sensitive index of cognitive load, and data implied that people with lower motivation for cognitive effort had a diminished physiological capacity to respond to rising cognitive demands. State affect appeared to influence motivation among people with current depression given that they were more willing to exert cognitive effort following a sad mood induction.

Anhedonia in Relation to Reward and Effort Learning in Young People with Depression Symptoms

Anhedonia, a central depression symptom, is associated with impairments in reward processing. However, it is not well understood which sub-components of reward processing (anticipation, motivation, consummation, and learning) are impaired in association with anhedonia in depression. In particular, it is unclear how learning about different rewards and the effort needed to obtain them might be associated with anhedonia and depression symptoms. Therefore, we examined learning in young people (N = 132, mean age 20, range 17-25 yrs.) with a range of depression and anhedonia symptoms using a probabilistic instrumental learning task. The task required participants to learn which options to choose to maximize their reward outcomes across three conditions (chocolate taste, puppy images, or money) and to minimize the physical effort required to obtain the rewards. Additionally, we collected questionnaire measures of anticipatory and consummatory anhedonia, as well as subjective reports of "liking", "wanting" and "willingness to exert effort" for the rewards used in the task. We found that as anticipatory anhedonia increased, subjective liking and wanting of rewards decreased. Moreover, higher anticipatory anhedonia was significantly associated with lower reward learning accuracy, and participants demonstrated significantly higher reward learning than effort learning accuracy. To our knowledge, this is the first study observing an association of anhedonia with reward liking, wanting, and learning when reward and effort learning are measured simultaneously. Our findings suggest an impaired ability to learn from rewarding outcomes could contribute to anhedonia in young people. Future longitudinal research is needed to confirm this and reveal the specific aspects of reward learning that predict anhedonia. These aspects could then be targeted by novel anhedonia interventions.

The Intensity Side of Volition

Abstract. Attaining sports or health goals requires not only high motivation but also the willpower to translate sport-behavior intentions into successful action. This volitional regulation calls for the mobilization of effort to overcome obstacles in the pursuit of goals. The present article provides a theoretical and empirical overview of motivation intensity theory ( Brehm & Self, 1989 ) – a conceptual framework that makes clear and testable predictions about effort mobilization in various contexts. First, we present the guiding principles of this theory and its operationalizations by measures of effort-related cardiovascular reactivity and physical handgrip force. Second, we review a selection of empirical tests of the basic assumptions of this theory and the impact of psychological moderator variables such as affect, fatigue, pain, and personality on effort mobilization. Finally, we discuss important implications of these findings for the sports and health domains and make suggestions for future research.

Self-Report Measures of Anhedonia and Approach Motivation Weakly Correspond to Anhedonia and Depression Assessed via Clinical Interviews

Self-report scales are popular tools for measuring anhedonic experiences and motivational deficits, but how well do they reflect clinically significant anhedonia? Seventy-eight adults participated in face-to-face structured diagnostic interviews: 22 showed clinically significant anhedonia, and 18 met criteria for depression. Analyses of effect sizes comparing the anhedonia and depression groups to their respective controls found large effects, as expected, for measures of depressive symptoms, but surprisingly weak effect sizes (all less than d=.50) for measures of general, social, or physical anhedonia, behavioral activation, and anticipatory and consummatory pleasure. Measures of Neuroticism and Extraversion distinguished the anhedonic and depressed groups from the controls at least as well as measures of anhedonia and motivation. Taken together, the findings suggest that caution is necessary when extending self-report findings to populations with clinically significant symptoms.

RZ Interval as an Impedance Cardiography Indicator of Effort-Related Cardiac Sympathetic Activity

Research on effort and motivation commonly assesses how the sympathetic branch of the autonomic nervous system affects the cardiovascular system. The cardiac pre-ejection period (PEP), assessed via impedance cardiography, is a common outcome, but assessing PEP requires identifying subtle points on cardiac waveforms. The present research examined the psychometric value of the RZ interval (RZ), which has recently been proposed as an indicator of sympathetic activity, for effort research. Also known as the initial systolic time interval (ISTI), RZ is the time (in ms) between the ECG R peak and the dZ/dt Z peak. Unlike PEP, RZ involves salient waveform points that are easily and reliably identified. Data from two experiments evaluated the suitability of RZ for effort paradigms and compared it to a popular automated PEP method. In Studies 1 (n = 89) and 2 (n = 71), participants completed a standard appetitive task in which each correct response earned a small amount of cash. As expected, incentives significantly affected PEP and RZ in both experiments. PEP and RZ were highly correlated (all rs ≥ 0.89), and RZ consistently yielded a larger effect size than PEP. In Study 3, a quantitative synthesis of the experiments indicated that the effect size of RZ's response to incentives (Hedges's g = 0.432 [0.310, 0.554]) was roughly 15% larger than PEP's effect size (g = 0.376 [0.256, 0.496]). RZ thus appears promising for future research on sympathetic aspects of effort-related cardiac activity.

Reward-Seeking Deficits in Major Depression: Unpacking Appetitive Task Performance with Ex-Gaussian Response Time Variability Analysis

Major depressive disorder (MDD) has extensive ties to motivation, including impaired response time (RT) performance. Average RT, however, conflates response speed and variability, so RT differences can be complex. Because recent studies have shown inconsistent effects of MDD on RT variability, the present research sought to unpack RT performance with several key improvements: (1) a sample of adults (n = 78; 18 MDD, 60 Control) free of antidepressant medication; (2) an unambiguously appetitive task with appealing incentives at stake; and (3) ex-Gaussian RT modeling, which can unconfound speed and variability by estimating parameters for the mean (Mu) and standard deviation (Sigma) of the normal component and the mean of the exponential component (Tau). The groups had comparable Mu and Sigma parameters, but the MDD group had a significantly larger Tau, reflecting greater intraindividual RT variability. The findings suggest that MDD's effect on average RT can stem from greater intraindividual variability, not from overall slowness. Possible mechanisms, such as impaired executive processes in MDD and difficulties maintaining stable mental representations of incentives, are considered.