PMID: 19015117;PMCID: PMC2566773;Abstract:
Psychological disengagement allows stigmatized individuals to cope with negative outcomes in stereotype-relevant domains, but its role in online performance monitoring and adjustment is unknown. This study examined how two forms of disengagement (devaluing and discounting) predict performance monitoring at an early (motivational) and later (interpretational) stage of error processing. Among minority college students, event-related brain activity was measured in response to errors on tasks described neutrally or as diagnostic of intelligence. Results found dissociable effects for error-related negativity (ERN) and later positivity (Pe). When the task was linked to intelligence, valuing academics predicted larger ERNs. Unexpectedly, discounting tendencies predicted smaller Pes when the task was described neutrally, a relationship that was attenuated and somewhat reversed when explicitly linking the task to intelligence. In the diagnostic condition, valuing also predicted more efficient behavioral responses to errors, whereas discounting predicted more negative task construals. Results suggest that among stereotype threatened minority students, devaluing has implications for early stage motivational processes involved in monitoring and responding to errors, whereas discounting may have implications for later construal processes. © The Author (2008). Published by Oxford University Press.
PMID: 18801582;PMCID: PMC2688527;Abstract:
Background: Tryptophan depletion (TD) reduces brain serotonin and may induce acute depressive symptomatology, especially among those with a history of Major Depression. Depressive response to TD among euthymic patients with a history of depression also predicts future depression. Better prediction might result by assessing a putative endophenotype for depressive risk, frontal electroencephalographic (EEG) asymmetry, in the context of TD. Method: Nine euthymic history-positive participants and nine controls were administered TD. Symptomatic and EEG frontal asymmetry data were collected for 6 h following TD, and clinical status was followed for the next 12 months. Results: The magnitude of TD-induced change in frontal EEG asymmetry significantly predicted the development of depression during the ensuing six to twelve months, and with greater sensitivity than symptomatic response. Limitations: The results are tempered by the small sample size. Conclusions: Despite the limited sample size, these preliminary results suggest that TD-induced changes in frontal EEG asymmetry may provide a more sensitive indicator of risk for imminent depression than symptomatic response to TD. © 2008 Elsevier B.V. All rights reserved.
Affective models of the mere exposure effect propose that repeated exposure to a stimulus increases the positive affect or reduces the negative affect toward the stimulus, whereas recent cognitive models propose that affect is not involved in the mere exposure effect. To test these competing predictions, participants repeatedly viewed photographs of women's faces and then viewed these women again (familiar) and novel women (unfamiliar) while facial muscle region activity and brain activity were recorded. Familiar stimuli were rated as more likable and they evoked more zygomatic (cheek) muscle region activity than unfamiliar stimuli. Interactions with individual differences occurred. Persons reporting less positive affect and persons reporting more negative affect at baseline evidenced more zygomatic activity to the familiar than to the unfamiliar. Persons with relatively less left frontal cortical activation at baseline evidenced a tendency toward a greater mere exposure effect. These results suggest that repeatedly exposing persons to nonreinforced stimuli increases their positive affective reactions to those stimuli.
Individual differences in resting asymmetrical frontal brain activity have been found to predict subsequent emotional responses. The question of whether frontal brain asymmetry can cause emotional responses has yet to be addressed. Biofeedback training designed to alter the asymmetry of frontal brain activity was therefore examined. Eighteen right-handed female participants were randomly assigned to receive biofeedback training designed to increase right frontal alpha relative to left frontal alpha (n = 9) or to receive training in the opposite direction (n = 9). Five consecutive days of biofeedback training provided signals of reward or nonreward depending on whether the difference between right (F4) and left (F3) frontal alpha exceeded a criterion value in the specified direction. Systematic alterations of frontal EEG asymmetry were observed as a function of biofeedback training. Moreover, subsequent self-reported affect and facial muscle activity in response to emotionally evocative film clips were influenced by the direction of biofeedback training.