Motivation for reward as a function of required effort: Dissociating the ‘liking’ from the ‘wanting’ system in humans

Recent studies investigating the neurobiology of reward motivation in animals have begun to deconstruct reward into separable neural systems involving the ‘liking’ of a reward (hedonic enjoyment of consumption) versus the ‘wanting’ of a reward (incentive salience to obtain reward). To date, however, it is unclear whether these systems are also separable in humans. We examined this question by manipulating the effort (clicking on a moving square) required for participants to obtain a reward (humorous versus non-humorous cartoon). Overall, as the required effort to view a humorous cartoon increased, participants were less likely to choose this reward. Moreover, individual differences in cartoon preference predicted cartoon choice at low levels of required effort, but not at high levels of required effort. These findings suggest that manipulating effort may be a valid method for dissociating the ‘liking’ from ‘wanting’ components of reward motivation in humans.

Category learning from equivalence constraints

Information for category learning may be provided as positive or negative equivalence constraints (PEC/NEC)—indicating that some exemplars belong to the same or different categories. To investigate categorization strategies, we studied category learning from each type of constraint separately, using a simple rule-based task. We found that participants use PECs differently than NECs, even when these provide the same amount of information. With informative PECs, categorization was rapid, reasonably accurate and uniform across participants. With informative NECs, performance was rapid and highly accurate for only some participants. When given directions, all participants reached high-performance levels with NECs, but the use of PECs remained unchanged. These results suggest that people may use PECs intuitively, but not perfectly. In contrast, using informative NECs enables a potentially more accurate categorization strategy, but a less natural, one which many participants initially fail to implement—even in this simplified setting.

Interpretation of Ambiguous Information in Girls at Risk for Depression

Research has consistently documented that depressed individuals process information in a negatively biased manner. There is little evidence, however, concerning whether these biases represent risk factors for depression, as is hypothesized by cognitive models. In the present study we investigated whether a particular cognitive bias observed in currently depressed individuals, the tendency to interpret ambiguous information negatively, characterizes daughters of depressed mothers, a population known to be at increased risk for depression. Following a negative mood induction, young daughters of depressed and never-disordered mothers completed two information-processing tasks in which their interpretations of emotionally ambiguous stimuli were evaluated. Daughters of depressed mothers interpreted ambiguous words more negatively and less positively, and ambiguous stories more negatively, than did daughters of never-disordered mothers. These results provide support for cognitive vulnerability models of depression.     

Selective attention to emotional faces following recovery from depression

This study was designed to examine attentional biases in the processing of emotional faces in currently and formerly depressed participants and healthy controls. Using a dot-probe task, the authors presented faces expressing happy or sad emotions paired with emotionally neutral faces. Whereas both currently and formerly depressed participants selectively attended to the sad faces, the control participants selectively avoided the sad faces and oriented toward the happy faces, a positive bias that was not observed for either of the depressed groups. These results indicate that attentional biases in the processing of emotional faces are evident even after individuals have recovered from a depressive episode. Implications of these findings for understanding the roles of cognitive and interpersonal functioning in depression are discussed.     

Mood regulation in depression: Differential effects of distraction and recall of happy memories on sad mood

Recent research suggests that the recall of positive memories plays an important role in mood regulation. In this study, the authors examined the ability of currently depressed, formerly depressed, and never-depressed participants to regulate sad mood through the recall of positive memories or through distraction. Although improvement in mood was found for all participants in response to distraction, under instructions to recall positive memories, never-depressed participants' moods improved, whereas formerly depressed participants' sad moods remained unchanged. It is important to note that depressed participants exhibited a worsening of their sad moods after recalling positive memories. These results suggest both that depression is associated with an impaired ability to use positive recall to regulate a sad mood and that this impairment continues to be evident following recovery.     

Neural correlates of rumination in depression

Rumination, or recursive self-focused thinking, has important implications for understanding the development and maintenance of depressive episodes. Rumination is associated with the worsening of negative mood states, greater affective responding to negative material, and increased access to negative memories. The present study was designed to use fMRI to examine neural aspects of rumination in depressed and healthy control individuals. We used a rumination induction task to assess differences in patterns of neural activation during ruminative self-focus as compared with a concrete distraction condition and with a novel abstract distraction condition in 14 participants who were diagnosed with major depressive disorder and 14 healthy control participants. Depressed participants exhibited increased activation in the orbitofrontal cortex, subgenual anterior cingulate, and dorsolateral prefrontal cortex as compared with healthy controls during rumination versus concrete distraction. Neural activity during rumination versus abstract distraction was greater for depressed than for control participants in the amygdala, rostral anterior cingulate/medial prefrontal cortex, dorsolateral prefrontal cortex, posterior cingulate, and parahippocampus. These findings indicate that ruminative self-focus is associated with enhanced recruitment of limbic and medial and dorsolateral prefrontal regions in depression. Supplemental materials for this article may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.     

Maladaptive coping, adaptive coping, and depressive symptoms: Variations across age and depressive state

Rumination has consistently been found to be associated with the onset and duration of major depressive episodes. Little research, however, has examined factors that may weaken the association between maladaptive coping, such as rumination, and depressive symptoms. In three samples of participants, including 149 never-depressed adolescent girls, 41 never-depressed women, and 39 depressed women, we examined whether generally adaptive forms of coping interacted with generally maladaptive forms of coping to predict depressive symptoms. Age-appropriate measures of coping and depression were administered to participants in each sample. In never-depressed females, maladaptive coping/rumination were more strongly related to depressive symptoms in the presence of lower levels of adaptive coping. The relation between depression and maladaptive coping/rumination was weaker in the context of higher levels of adaptive coping. In contrast, for the depressed females, we found main effects for rumination and adaptive coping, with higher levels of rumination and lower levels of adaptive coping being associated with higher levels of depressive symptoms. The present findings highlight how adaptive coping and maladaptive coping, including rumination, differentially relate to each other and depressive symptoms depending on individuals' current depressive state.     

Construct accessibility and depression: an examination of cognitive and affective factors

Two studies in which the parameters of construct accessibility in depression were examined are reported. In Experiment 1, depressed and nondepressed subjects were required to name the colors of tachistiscopically presented depressed-content, neutral-content, and manic-content words. Because of the predicted accessibility and interference effects of the depressed-content words, the depressed subjects were expected to demonstrate longer response latencies to these words than to the non-depressed-content words. This response pattern was found for the depressed subjects; the nondepressed subjects did not demonstrate differential response latencies. In Experiment 2, a mood-induction paradigm was used to investigate whether the interference effects obtained in Experiment 1 were due to temporary mood differences between the depressed and nondepressed subjects, or were a function of more stable depression-associated patterns of information processing. Although predicted group differences were obtained on a mood adjective checklist, no effects were found for task performance. These results suggest that transient mood is not a sufficient explanation for the results obtained in Experiment 1. The implications of the present findings for the understanding of both construct accessibility and depression are discussed, and directions for future research are suggested.