Emotion interacts with numerous areas of cognition, including memory, decision-making, and attention (Dolan, 2002). In this dissertation, I conduct four experiments investigating the role of emotion on selective visual attention. In Chapter 1, I describe basic emotion research and the “scope” of selective attention. I outline previous research on the effects of happiness and anxiety on selective attention, some potential mechanisms of these effects, and their practical significance.

In Chapter 2, I present an experiment building on prior findings that positive moods broaden the scope of selective attention (Rowe, Hirsh, & Anderson, 2007). I also present advantages and disadvantages of methods to induce and assess emotional states. In my experiment, participants showed greater flanker interference in a happy mood and less flanker interference in an anxious mood, indicating broadened and narrowed attentional scopes, respectively.

In Chapter 3, I present two experiments exploring the role of mood in featural selection. I outline evidence for a featural scope of attention and changes to the flanker task to incorporate featural selection. When in an anxious mood, participants showed reduced flanker interference when a feature distinguished the target from the flankers, but more interference when the flankers shared the feature. In contrast, in a positive mood, these participants showed relatively non-selective featural attention. A follow-up experiment found that this effect was modified by task context.

In Chapter 4, I examine mood influences in a visual search task similar to the flanker task. I outline the importance of visual search and reasons why mood states might influence it. In this search task, no reliable mood effects were found on visual search efficiency, except for a potential between-subjects effect. I interpret these findings in light of attentional theory and potential issues with the search task.

In Chapter 5, I present overall conclusions and limitations, as well as how this research fits into the existing literature. Overall, participants' spatial and featural selection is broadened by happy moods and narrowed by anxiety, but this may not influence preattentive processing in visual search. I conclude with areas of improvement for future studies and research directions based on this work.