Electrophysiological investigations of attentional mechanisms governing emotional information processing

There is an on-going debate in the literature concerning the contribution of automatic and controlled processes underlying emotional effects on cognition. The current thesis had two objectives: (1) to investigate attentional mechanisms in the visual perception of and memory for emotional events and (2) to examine the influence of individual differences in fear, anxiety, and approach systems on emotional attention and memory. In Chapter 2 we demonstrate trait-congruency effects in emotional information processing across a range of cognitive domains. More importantly, we show that by examining trait processes underlying trait-congruency effects in emotional information processing one is able to gain valuable insight into how differences in personality traits gives rise to these trait-congruency effects. In Chapter 3 we reveal that early stage of exogenous attention to emotional stimuli are modulated by the valence-arousal interactions of the emotional stimulus, while later stages of exogenous attention appear to be driven by the arousal value of the stimulus. More importantly, individual differences in the fear system and impulsivity dimension influenced attentional biases for emotional stimuli, underlining the importance to differentiate fear from anxiety and reward components from impulsivity. In Chapter 4 we show that divided attention at encoding does not further modulate the influence of affective content on recognition memory performance, but electrophysiological results provide evidence that this is due to different underlying mechanisms. Specifically, electrophysiological results suggest that visual attentional processes play a role in the recollection based recognition of positive/high-arousal images, but not of negative images. Thus, recollection of positive/high-arousal images requires a more effortful search for the memory trace, while negative images, regardless of arousal value, are recollected less effortful, even when attention at encoding is limited. This effect mediated the negative relationship between reward reactivity and recognition performance for positive/high-arousal images presented under conditions of high perceptual load, indicating that dysfunctional reward reactivity is related to disinhibited behavior. In Chapter 5 we provide evidence that the late posterior negativity is modulated by attentional mechanisms rather than by memory specific processes. That is, instead of being modulated by the amount of information needed for the reconstruction of the study episode, we put forward that this electrocortical component reflects controlled stimulus evaluation processes that are, at least in part, modulated by task difficulty. Overall, the results of the present thesis show that emotions exert their influence on sensory information processing via automatic, bottom-up mechanisms and via controlled, top-down processes. Further, elevated activation of fear, anxiety, and approach systems are associated with dysfunctional emotion-attention interactions in sensory information processing. Clarifying the contribution of attentional mechanisms in emotional information processing will help to gain a better understanding of affective disorders characterized by attentional and memory biases, which is necessary for the development of interventions that can be useful in the regulation of dysfunctional attention allocation and memory formation.