Cognitive control refers to the brain's ability to control attention and other cognitive functions in the service of intention-driven behaviors; moreover, it is an essential aspect in cognition. Cognitive control is commonly evaluated through the so-called conflict adaptation effect, which is revealed through trial-to-trial changes in performance after experiencing cognitive conflict. The conflict monitoring theory is a prominent theory intended to describe conflict adaptation and explain how cognitive control might be engaged in the face of conflict. A passive carryover account, originally aimed at explaining task switching and based on parallel distributed processing models, may represent a superior alternative to the conflict monitoring account. In the carryover account, passive inertia of the cognitive control state explains the trial-to-trial modulation of conflict effects. One problem with conflict adaptation is that the typical paradigms used to create conflict adaptation often include trial-to-trial repetitions that mimic the same performance pattern through priming. Conflict monitoring theory also has difficulty explaining other issues such as whether conflict adaptation is task-specific. A meta-analysis of the so-called conflict adaptation effect suggests trial-to-trial repetitions do not entirely account for conflict adaptation effects, but these effects do appear to be task-specific. The meta-analysis also suggests the withdrawal of control is episodic rather than temporal and conflict adaptation may be sensitive to experimental session length. A novel eye-tracking paradigm addresses the timing of control engagement. The results suggest dynamic regulation of attention coupled with conflict detection. This more tightly coupled detection and regulation process in the context of conflict adaptation is more consistent with a carryover account than what would be expected from the conflict monitoring theory. A subsequent eye-tracking paradigm further supported that trial-to-trial modulations of control are generally more consistent with a carryover account than they are with the conflict monitoring theory. Overall, the empirical evidence points toward a carryover model of cognitive control. / 2016-10-17

East African pastoralist societies are characterised by their inherent adaptability to climatic variability, by way of their sophisticated resource management systems and social institutions which provide the knowledge and flexibility needed to respond effectively to risk and uncertainty. However, the impacts of future climate change, in addition to the myriad of social, political, economic and environmental pressures associated with integrating into an increasingly inter-connected globalised system, may be unprecedented in their scope and range, and are likely to undermine their ability to pursue successful livelihoods while putting at risk the things they value. Responses to these challenges need to be based on an accurate and evidence-based understanding of the complexity and synergistic nature of multiple stressors, in order to avoid narrow quick-fix solutions which may undermine resilience and human security in the longer term. This social science research has used a multi-methods approach to fulfil the following objectives: identify the range of stressors impacting livelihoods and wellbeing within the study areas; investigate the multi-directional associations between climate variability and conflict; and evaluate the influence of development interventions on the characteristics of social resilience. Fieldwork was undertaken in collaboration with two non-governmental organisations, with data derived from ethnographic observations and shadowing, participatory rural appraisal, focus group discussions, semi-structured interviews and household livelihood surveys. Results find that communities within the study areas are faced with multiple and interacting pressures on their lives and livelihoods, and that while climate change impacts are likely to compound vulnerability and undermine human security, they cannot be isolated from the broader context, or from local priorities and lived realities. Violent conflict is identified as being more closely associated with periods of abundant rainfall than those of scarcity or resource competition, with climate-related hazards such as drought being more likely to result in reconciliation and cooperation. Conflict is driven primarily by the broader political economy within the region, along with land boundary disputes and the ethnically-based nature of governance and resource allocation. Pastoralist systems are found to inherently contain many of the characteristics of socio-ecological resilience, with development interventions having the potential to build on these strengths in order to simultaneously promote adaptive capacity and build peace. However, the narrow focus on specific risks by organisations within the study areas, without a broader integration of responses to multiple stressors, may lead to path dependency and maladaptation, and could act to undermine resilience in the longer term. This thesis contributes qualitative empirical evidence to the climate security debate, and demonstrates that peace and cooperation are more likely outcomes than violence in pastoralist regions during periods of climate-related stress. It also provides an analysis of the extent to which development interventions inherently support or constrain adaptive capacity and social resilience to climate change, conflict, and other livelihood pressures.

Obsessive-compulsive disorder (OCD) is associated with diminished quality of life and cognitive control dysfunction. Conflict adaptation is a reflection of cognitive control, and consists of the ability to detect conflict in previous trials and adjust performance on current trials. Conflict adaptation is thought to rely on interplay between the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (dlPFC) for detecting conflict and signaling for increases in control, respectively. We hypothesized that individuals with OCD would show reduced conflict adaptation effects in response times, error rates, ACC activation, and dlPFC activation when compared with healthy control subjects. We also expected diminished conflict adaptation to be associated with poorer quality of life in those with OCD. Nineteen individuals with OCD and twenty psychiatrically-healthy controls completed a Stroop task while response times, error rates, and fMRI data were recorded. 2-Group (OCD, control) x 2-Previous Trial Congruency (congruent, incongruent), x 2-Current Trial Congruency (congruent, incongruent) ANOVAs were conducted for both behavioral and fMRI data. Indices of conflict adaptation were correlated with quality of life scores. There was a significant response time conflict adaptation effect collapsed across groups; however, there were no between-groups interactions or main effects. No error rate conflict adaptation was observed at any level of the analysis. On fMRI analyses, the dlPFC showed increased activation on incongruent relative to congruent trials collapsed across groups; however, no ACC activation differences were observed between current incongruent and congruent trials. Conflict adaptation-related activation was noted in the ACC collapsed across groups. The between-groups ANOVA revealed a significant cluster in the ACC with control participants showing greater ACC, medial prefrontal cortex, and left orbitofrontal cortex conflict adaptation activation-related activation relative to individuals with OCD. No between-groups differences were seen in the dlPFC. Conflict adaptation was not significantly related to quality of life. Individuals with OCD may use different neural processes to achieve similar behavioral results to those of healthy controls. Alternative explanations of conflict adaptation effects such as temporal learning theory are also discussed. Our hypothesized model for the ACC and dlPFC functioning as the evaluative and regulative components of cognitive control was only partly supported. ACC and dlPFC activation appeared to highlight different roles, but these roles may be independent rather than existing in a feedback loop. Although quality of life is significantly diminished in individuals with OCD, this loss of quality of life does not appear to be mediated by conflict adaptation differences.

In multitasking, the execution of a prioritized task is in danger of crosstalk by the secondary task. Task shielding allows minimizing this crosstalk. However, the locus and temporal dynamics of crosstalk effects and further sources of influence on the execution of the prioritized task are to-date only vaguely understood. Here we combined a dual-task paradigm with an action dynamics approach and studied how and according to which temporal characteristics crosstalk, previously experienced interference and previously executed responses influenced participants' mouse movements in the prioritized task's execution. Investigating continuous mouse movements of the prioritized task, our results indicate a continuous crosstalk from secondary task processing until the endpoint of the movement was reached, although the secondary task could only be executed after finishing execution of the prioritized task. The motor movement in the prioritized task was further modulated by previously experienced interference between the prioritized and the secondary task. Furthermore, response biases from previous responses of the prioritized and the secondary task in movements indicate different sources of such biases. The bias by previous responses to the prioritized task follows a sustained temporal pattern typical for a contextual reactivation, while the bias by previous responses to the secondary task follows a decaying temporal pattern indicating residual activation of previously activated spatial codes.

Background. Feelings of doubt and perseverative behaviours are key symptoms of obsessive–compulsive disorder (OCD) and have been linked to hyperactive error and conflict signals in the brain. While enhanced neural correlates of error monitoring have been robustly shown, far less is known about conflict processing and adaptation in OCD. Method. We examined event-related potentials during conflict processing in 70 patients with OCD and 70 matched healthy comparison participants, focusing on the stimulus-locked N2 elicited in a flanker task. Conflict adaptation was evaluated by analysing sequential adjustments in N2 and behaviour, i.e. current conflict effects as a function of preceding conflict. Results. Patients with OCD showed enhanced N2 amplitudes compared with healthy controls. Further, patients showed stronger conflict adaptation effects on reaction times and N2 amplitude. Thus, the effect of previous compatibility was larger in patients than in healthy participants as indicated by greater N2 adjustments in change trials (i.e. iC, cI). As a result of stronger conflict adaptation in patients, N2 amplitudes were comparable between groups in incompatible trials following incompatible trials. Conclusions. Larger N2 amplitudes and greater conflict adaptation in OCD point to enhanced conflict monitoring leading to increased recruitment of cognitive control in patients. This was most pronounced in change trials and was associated with stronger conflict adjustment in N2 and behaviour. Thus, hyperactive conflict monitoring in OCD may be beneficial in situations that require a high amount of control to resolve conflict, but may also reflect an effortful process that is linked to distress and symptoms of OCD.

In multitasking, the execution of a prioritized task is in danger of crosstalk by the secondary task. Task shielding allows minimizing this crosstalk. However, the locus and temporal dynamics of crosstalk effects and further sources of influence on the execution of the prioritized task are to-date only vaguely understood. Here we combined a dual-task paradigm with an action dynamics approach and studied how and according to which temporal characteristics crosstalk, previously experienced interference and previously executed responses influenced participants' mouse movements in the prioritized task's execution. Investigating continuous mouse movements of the prioritized task, our results indicate a continuous crosstalk from secondary task processing until the endpoint of the movement was reached, although the secondary task could only be executed after finishing execution of the prioritized task. The motor movement in the prioritized task was further modulated by previously experienced interference between the prioritized and the secondary task. Furthermore, response biases from previous responses of the prioritized and the secondary task in movements indicate different sources of such biases. The bias by previous responses to the prioritized task follows a sustained temporal pattern typical for a contextual reactivation, while the bias by previous responses to the secondary task follows a decaying temporal pattern indicating residual activation of previously activated spatial codes.