| Emotion has been shown to improve perception, and to both facilitate and impair selective visual attention. The conjoint effect of emotion with attention has been demonstrated across a range of tasks measuring accuracy and response speed. Of particular interest in this dissertation are the behavioral and neural correlates of emotion's cost to visual attention allocation, and the individual differences across observers that modulate the magnitude of this effect. Costs of emotion to visual attention are assessed by measuring decreases in (1) contrast sensitivity, a low-level visual perceptual ability, and (2) word identification accuracy. Chapters 1 and 2 utilize a visual psychophysics spatial cuing paradigm in which emotional or neutral face cues direct attention prior to an orientation discrimination task dependent on contrast sensitivity. An incongruent spatial relationship of cues and oriented targets has previously been shown to alter contrast sensitivity. We show that observer handedness (Chapter 1), trait anxiety and sex of the observer (Chapter 2) also modulate this effect. Chapter 3 utilizes a variant of the attentional blink paradigm to investigate the neural correlates of emotion's cost to temporal attention. Emotional distracter words disrupt processing of neutral target words in a rapid serial visual presentation. We show that brain regions underlying bottom-up emotional responses, such as the amygdala, may help direct attention to distracters via the orbitofrontal cortex and intraparietal sulcus during emotional costs. Emotional costs to attention may be worsened in individuals who engage the dorsolateral prefrontal cortex less (primarily observers low in self-reported attentional control and high in trait anxiety). As opposed to facilitative effects of emotion to attention, costs are suggested to occur when bottom-up emotional responses out-compete top-down attentional control mechanisms. Similar neural circuitry may underlie emotional costs in both the spatial and temporal attention domains. |
