Cerebral Asymmetries, Motivation, and Cognitive Processing: An Analysis of Individual Differences

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Title: Cerebral Asymmetries, Motivation, and Cognitive Processing: An Analysis of Individual Differences
Authors: Düsing, Rainer
Thesis advisor: Prof. Dr. Julius Kuhl
Thesis referee: PD Dr. Markus Quirin
Abstract: Everyday life experience tells us that individual differences apparently matter. Although confronted with the same situation, individuals seem to act and react in different ways. On a behavioral and self-report level, individual differences are well documented. Over the past decades, they have been systematically assessed and embedded in complex theories of personality. On the other hand, the influence of personality differences on cognitive processes and their cerebral substrate is far from being entirely understood. Especially the complex interplay of two or more aspects, like individual differences (e.g., in motivational processes), cognitive functions (e.g., intuition), cerebral activation and lateralization, and humoral processes (e.g., cortisol), are seldom aim of psychological research. The Personality Systems Interaction (PSI) theory (Kuhl, 2000, 2001) provides a theoretical framework, which tries to incorporate the above-mentioned aspects. On the background of PSI theory, the aim of the present work was to investigate differences in motivational processing and how they are related to hemispherical asymmetries, cognitive processing, and humoral reactivity. Each of the three research articles presented throughout the present work tackles different aspects of this general research question. For this, a variety of different methodological techniques were used (e.g., questionnaires, implicit measures, electroencephalography, etc.) to approach the aforementioned goal. The first research paper presented in the current work examines the relationship between the implicit affiliation motive and intuition, as a form cognitive processing. Previous research already demonstrated that affiliation-laden primes facilitate intuitive thought (Kuhl & Kazén, 2008). Therefore, it could be expected that trait affiliation motive would also be correlated with intuition. Intuition in turn is thought to be a function of right hemispheric processes. An association between trait affiliation and intuition could therefore indirectly indicate a lateralization to the right side for affiliation. With the first study of the present work, the author tested this association. Thirty-nine students filled in the Operant Motive Test for the assessment of implicit affiliation, a variant of the Thematic Apperception Test. Then, 9 months later, participants engaged in a Remote Associates Test in which they intuitively had to indicate whether three words are semantically related. As expected, the implicit affiliation motive significantly predicted the accuracy of identifying related word triads. No other implicit or explicit measure, nor state or trait positive affect was associated with intuition. With the second research article, the aforementioned indirect association between affiliation and lateralized processing was investigated more directly. Previous research on relationships between personality and EEG resting state frontal asymmetries mainly focused on individual differences with respect to motivational direction (i.e., approach vs. withdrawal). By contrast, the second article investigated frontal asymmetries as a function of individual differences in implicit affiliation motive. The goal was not only to contribute to the validation of PSI theory and to the investigation of the laterality of the affiliation motive, but also to disentangle the contribution of different social motives to frontal EEG asymmetries. The consideration of social motives, such as the affiliation motive, seemed to be necessary, because a recent meta-analysis showed that the association between approach motivation and frontal asymmetries is negligible or that unidentified moderators drive this association. From previous research and the results from the first paper presented in the current work, an association between affiliation motive and right frontal activity was predicted. Additionally, to control for possible associations with motivational direction, trait behavioral inhibition, behavioral activation, and anger were assessed and correlated with frontal asymmetries. Seventy-two right-handed students were tested. As expected and in accordance with the findings from the first paper, the author found that relative right frontal activity (indicated by low alpha frequency power) was associated with the affiliation motive. To explore brain regions responsible for this association at scalp sites, a source localization algorithm was applied. Intracranial distribution of primary current densities for the alpha band spectrum in source space was estimated and correlated with implicit affiliation scores. A significantly correlating area could be identified in the right ventromedial prefrontal cortex (Brodmann Area 10). No other associations at scalp sites or in source space could be found for motivational direction. The third research article presented in the current work highlights motivational differences slightly different from those presented above. It deals with dynamic motivational processes, such as action orientation, and how they moderate the association between cerebral asymmetries and the physiological stress reaction. Hypothalamus pituitary adrenocortical (HPA) system activity and frontal brain asymmetries have both been linked to stress and emotion but their relationship remains unclear, especially when additionally considering individual differences. Therefore, participants were exposed to public speaking stress while salivary cortisol levels (as a marker of HPA activity) and resting frontal EEG alpha asymmetries were assessed before and after stress induction. The results indicate that higher post stressor cortisol levels were associated with higher relative left frontal activity. State oriented participants showed a stronger association between cortisol response and left frontal activity than action oriented participants. The above-mentioned findings are discussed referring to PSI theory and their possible implications. Additionally, shortcomings of the present research and possible remedies will be presented.
URL: https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2015071713339
Subject Keywords: Motivation; Alpha-Asymmetrie; Intuition; Cortisol
Issue Date: 17-Jul-2015
License name: Namensnennung-NichtKommerziell-KeineBearbeitung 3.0 Unported
License url: http://creativecommons.org/licenses/by-nc-nd/3.0/
Type of publication: Dissertation oder Habilitation [doctoralThesis]
Appears in Collections:FB08 - E-Dissertationen

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