Decreased approach motivation in depression

The present study examined relations between choice preference and reaction time to emotionally valenced words, dysphoric symptoms (BDI), and dysfunctional attitudes (DAS) in clinically depressed (CD; n= 61), previously depressed (PD; n= 42), and never depressed controls (ND; n= 46). The results showed: (1) NDs and PDs exhibited a choice preference for the relatively more positive words and differed significantly from CDs; (2) PDs and CDs exhibited longer reaction time and differed significantly from NDs; and (3) BDI and DAS were positively associated with reaction time to positively valenced words, whereas no associations were found for reaction time to negatively valenced words. The increased reaction time, in PDs and CDs, is discussed as a possible vulnerability factor to depression, which may be related to decreased approach motivation.     

Blunted reward responsiveness prospectively predicts emotional distress when exposed to a naturalistic stressor

Both stress and blunted reward responsiveness have been identified as core risk factors of depression. Whether blunted reward responsiveness increases psychological vulnerability to real-life stress from a dynamic perspective (from stress reactivity to recovery) has not been investigated. By utilizing a real-world stressful event (i.e. the final examination), this study aimed to explore the role of reward responsiveness in the stress-emotional distress relationship during stress reactivity and recovery phases. We followed 57 undergraduates with three assessments, from six weeks before examination weeks (T1, baseline), one day before the examinations (T2) to two weeks after the examinations (T3), therefore, covering stress reactivity (T1 to T2) and recovery (T2 to T3) phases. At baseline, reward responsiveness was measured as the Reward Positivity (RewP) in the doors task. Stress and emotional distress (anxiety and depression) were reported at T1, T2 and T3 to capture their dynamic changes. Results showed that self-report stress levels significantly increased from T1 to T2 (stress reactivity phase) and decreased from T2 to T3 (stress recovery phase). Furthermore, blunted reward responsiveness at baseline prospectively predicted emotional distress during the stress reactivity phase but not the recovery phase. Specifically, during the stress reactivity phase, higher perceived stress was associated with greater anxiety and depression only in participants with relatively smaller residual RewP amplitudes but not in participants with relatively larger residual RewP amplitudes. Our study demonstrated that a blunted reward responsiveness is a vulnerable factor of depression, especially when exposed to stress. Our findings provide insights into prevention and intervention for stress-related disturbance.     

Anticipatory pleasure predicts motivation for reward in major depression

Anhedonia, the lack of interest or pleasure in response to hedonic stimuli or experiences, is a cardinal symptom of depression. This deficit in hedonic processing has been posited to influence depressed individuals' motivation to engage in potentially rewarding experiences. Accumulating evidence indicates that hedonic processing is not a unitary construct but rather consists of an anticipatory and a consummatory phase. We examined how these components of hedonic processing influence motivation to obtain reward in participants diagnosed with major depression and in never-disordered controls. Thirty-eight currently depressed and 30 never-disordered control participants rated their liking of humorous and nonhumorous cartoons and then made a series of choices between viewing a cartoon from either group. Each choice was associated with a specified amount of effort participants would have to exert before viewing the chosen cartoon. Although depressed and control participants did not differ in their consummatory liking of the rewards, levels of reward liking predicted motivation to expend effort for the rewards only in the control participants; in the depressed participants, liking and motivation were dissociated. In the depressed group, levels of anticipatory anhedonia predicted motivation to exert effort for the rewards. These findings support the formulation that anhedonia is not a unitary construct and suggest that, for depressed individuals, deficits in motivation for reward are driven primarily by low anticipatory pleasure and not by decreased consummatory liking.     

Anhedonic symptoms of depression are linked to reduced motivation to obtain a reward

People with depression report reduced motivation to obtain a reward and reduced affective responses to reward. However, studies focusing on the relation between anhedonia and deficits in reward processing are scarce. Furthermore, studies investigating wanting through cardiovascular reactivity and liking through facial electromyography in human beings are also scarce. In this study, we used the Temporal Experience of Pleasure Scale score as a continuous predictor variable of anhedonia and we manipulated two within-person conditions (wanting vs. liking). Participants earned money if their performance on a memory task exceeded a particular standard. As expected, effort-related cardiovascular reactivity and self-reports during the anticipatory phase were lower for participants scoring high on anhedonia. Moreover, task performance outcomes were worse for highly anhedonic participants. However, the zygomaticus major muscle’s activity during the consummatory phase was unrelated to the anhedonia score. The present study underlines the importance of anhedonic symptoms, particularly in reduced anticipatory motivation to obtain a reward.     

Frontal brain asymmetry and reward responsiveness: a source-localization study

The influence of approach and avoidance tendencies on affect, reasoning, and behavior has attracted substantial interest from researchers across various areas of psychology. Currently, frontal electroencephalographic (EEG) asymmetry in favor of left prefrontal regions is assumed to reflect the propensity to respond with approach-related tendencies. To test this hypothesis, we recorded resting EEG in 18 subjects, who separately performed a verbal memory task under three incentive conditions (neutral, reward, and punishment). Using a source-localization technique, we found that higher task-independent alpha2 (10.5-12 Hz) activity within left dorsolateral prefrontal and medial orbitofrontal regions was associated with stronger bias to respond to reward-related cues. Left prefrontal resting activity accounted for 54.8% of the variance in reward bias. These findings not only confirm that frontal EEG asymmetry modulates the propensity to engage in appetitively motivated behavior, but also provide anatomical details about the underlying brain systems.     

Selective responsiveness of chronically ill children to assessments of depression.

Many investigators have noted that depression is a common symptom among pediatric cancer patients. However, prevalence rates vary widely across studies. This variation in prevalence rates may be due, in part, to selective reporting of patients based on measures used and environmental cues. In this study, we evaluated 50 chronically ill pediatric patients (19 cancer and 31 diabetic patients) for their use of selective reporting of depression. Factors in the 2 x 2 design were Intervention (disclosure videotape and cartoon videotape) and Examiner (familiar examiner and unfamiliar examiner). In the Intervention manipulation, subjects were shown either a videotape prompting the child that self-disclosure was appropriate or a tape of a cartoon (control condition). In the Examiner manipulation, subjects were administered the experimental measures by either a familiar (parent) or unfamiliar (research assistant) examiner. Dependent variables were the Children's Depression Inventory (CDI; Kovacs, 1981), the Depression scale of the Roberts Apperception Test for Children (RATC; McArthur & Roberts, 1982), and a depression measure taken from the Child Behavior Checklist (CBCL; Achenbach & Edelbrock, 1983). As hypothesized, the Examiner x Intervention interaction revealed that children who did not view the disclosure videotape and who were tested by an unfamiliar examiner gave significantly lower self-reports of depression on the CDI than children in the other conditions. However, parent and child projective reports of depression did not vary as a function of experimental condition. The results are interpreted as selective responding on the part of pediatric patients. Limitations of assessing internal psychological states in children are discussed.     

Something funny happened to reward

The human reward system has been shown to be activated by a wide range of reinforcers, including food, money, sex, drugs, and beauty. Now, a recent fMRI study has found mesolimbic reward activation associated with humorous cartoons, providing a neurobiological link between theories of humour and hedonic processes in the brain.     

The psychological distance to reward

Pigeons' responses in the presence of two concurrently available (initial-link) stimuli produced entry into one of two different and mutually exclusive terminal link stimuli according to identical but independent variable-interval schedules. In one experiment, a two-component chained fixed-interval schedule produced food in one terminal link while a simple fixed-interval schedule produced food in the other terminal link. When the interreinforcement intervals were equal in the two terminal links (i.e., the simple fixed-interval was twice the size of each of the components in the chained schedule) pigeons preferred the simple fixed-interval as measured by their relative rates of responding in the concurrently available initial links. This preference increased as the duration of the terminal links increased. The preference could be reversed by making the simple fixed-interval schedule sufficiently longer than the chained schedule. In the second experiment, the terminal links consisted of two- vs three-component chained fixed-intervals, again with equal interreinforcement intervals. Pigeons preferred the two-component chain to the three-component chain, although these results were less consistent and less dramatic than those in the first experiment. Again, preference increased as the duration of the terminal links increased. The results show that an organism's choice for a schedule will be substantially lowered by the chaining operation even when the interreinforcement interval remains constant.     

Order of partial and consistent reward,reward magnitude shift,and resistance to extinction

In a separate-phase runway experiment with rats, four schedules involving partial (P) and consistent (C) reward (CC, CP, PC, and PP) were crossed with three reward magnitude shift conditions (upshift, nonshift, and downshift). The data revealed three major findings: (a) Reward magnitude downshift generally led to rapid extinction; (b) consistent reward prior to partial reward (CP) resulted in slower extinction than the reverse order (PC) under conditions of reward magnitude shift (particularly downshift); and (c) the relative performance of PC and CP under conditions of reward magnitude shift was reversed from postshift to extinction. On the basis of these data it was suggested that processes not presently identified by reinforcement level theory and stimulus analyzer theory influence extinction following separate-phase acquisition. A modification of reward level theory was presented to provide an account of extinction performance following separate-phase reward reduction.     

Fading to increase heterosexual responsiveness in homosexuals

Heterosexual responsiveness, measured by penile responses and reports of behavior, was strengthened in three homosexuals through a fading procedure. Using two slide projectors, colored slides of nude females were superimposed on colored slides of nude males. As the sexual response was emitted, the nude male was faded out and the nude female faded in. Heterosexual arousal decreased when the fading procedure was reversed or stopped and increased once again when fading was resumed. Homosexual arousal remained high during this experiment but had decreased in two subjects at follow-up. The results suggest that fading was responsible for altering stimulus control of sexual arousal and that aversive techniques may not be necessary in the treatment of sexual deviation.     

Transfer between downshift in reward magnitude and continuous delay of reward

Two separate experiments were conducted to investigate transfer of persistence between delay and a downshift in reward magnitude. In the first experiment, experimental rats were initially downshifted in reward magnitude and later tested for persistence to continuous delay of large reward. It was found that these rats were more persistent to the effects of delay than control rats which did not receive prior experience with a downshift in reward magnitude. In the second experiment, experimental rats were first trained to receive large reward under delayed conditions and then tested for persistence to a downshift in reward magnitude. Compared to control rats which received no prior experience with delay, the experimental rats showed a significantly smaller negative contrast effect. The results were interpreted as supporting Amsel's theory of persistence as well as Capaldi's recent interpretation of contrast effects.     

The reward probability index: design and validation of a scale measuring access to environmental reward

Behavioral models of depression implicate decreased response-contingent positive reinforcement (RCPR) as critical toward the development and maintenance of depression (Lewinsohn, 1974). Given the absence of a psychometrically sound self-report measure of RCPR, the Reward Probability Index (RPI) was developed to measure access to environmental reward and to approximate actual RCPR. In Study 1 (n = 269), exploratory factor analysis supported a 20-item two-factor model (Reward Probability, Environmental Suppressors) with strong internal consistency (α = .90). In Study 2 (n = 281), confirmatory factor analysis supported this two-factor structure and convergent validity was established through strong correlations between the RPI and measures of activity, avoidance, reinforcement, and depression (r = .65 to .81). Discriminant validity was supported via smaller correlations between the RPI and measures of social support and somatic anxiety (r = – .29 to – .40). Two-week test–retest reliability was strong (r = .69). In Study 3 (n = 33), controlling for depression symptoms, hierarchical regression supported the incremental validity of the RPI in predicting daily diary reports of environmental reward. The RPI represents a parsimonious, reliable, and valid measure that may facilitate understanding of the etiology of depression and its relationship to overt behaviors.     

Intolerance to delayed reward in girls with multiple suicide attempts

Impulsivity has been conceptualized as influencing the expression of suicidal behavior. Adolescence is a developmental period characterized both by a relatively high rate of suicide attempts and a high level of impulsivity. The current study examined two behavioral measures (delay reward and disinhibition) and one self-report measure of impulsivity among girls with suicide attempt histories. Girls with multiple suicide attempts performed more impulsively on measures of delayed reward, and had higher self-ratings of depression and aggression than girls with either one or no suicide attempts. The multiple attempter girls' preference for immediate gratification may directly increase vulnerability to suicidal acts in the context of distressing states or indirectly increase risk by creating poor life experience over time.     

Psychological distance to reward: A human replication

Choice behavior in college students was examined in two experiments using the concurrent-chains procedure. In both experiments, the concurrent chains were presented on a microcomputer in the form of an air-defense game in which subjects used two radar systems to detect and subsequently destroy enemy aircraft. Access to one of two radar systems was controlled by a pair of independent concurrent variable-interval 60-s schedules with a 4-s changeover delay always in effect. In the terminal link, the appearance of an enemy aircraft was determined by a pair of differentially segmented fixed-time schedules (Experiment 1) or fixed-interval schedules (Experiment 2) of equal overall duration. In Experiment 1, the terminal-link duration was either 20 s or 40 s, and subjects preferred the unsegmented to the segmented intervals. In Experiment 2, the duration was either 10 s or 60 s, and the reinforcement contingencies required responding during the terminal link. Prior to the reinstatement of the initial link, subjects estimated the duration of the terminal-link schedule. Segmentation affected choice in the 60-s conditions but not in the 10-s ones. Preference for the unsegmented schedule was correlated with an overestimation of the durations for the segmented schedules. These results replicated those found in animal experiments and support the notion of increasing the psychological distance to reward by segmenting a time-based schedule of reinforcement.     

Infants' responsiveness to line junctions in curved objects

Several empirical studies demonstrate that infants under 6-7 months of age are unable to extract static-monocular depth information from their environment. The aim of this study was to extend these findings by using a three-dimensional structure indicated by curved Y junctions. Infants 5 and 8 months of age were habituated to the line drawing of a cylinder. During test trials, the infants viewed two displays, one in which a surface marking had been deleted from the habituation figure and one in which an edge had been erased. An ANOVA revealed that the 8-month-old subjects looked significantly longer at the dishabituation display lacking the edge, whereas the 5-month-olds did not. The results provide evidence that 8-month-old infants distinguish between lines indicating edges and lines indicating markings and that they are able to use line junctions to perceive line drawings as depictions of three-dimensional objects in the picture plane.