| dc.description.abstract | Attention research has long investigated the mechanisms by which sensory information is selectively filtered for neural representation. Models for visual selective attention initially formed a theoretical dichotomy in which goal-oriented or salience-driven mechanisms were argued as the predominant modes for attentional selection. However, this theoretical dichotomy was challenged when new experimental findings could not be reduced to goal-oriented or salience-driven mechanisms. These results were grouped into a new component of attentional control by an experience-driven mechanism and expanded models of selective attention into a theoretical trichotomy under the third label selection history.
In the context of attention research, threat has been investigated primarily by measuring rapid orienting towards threatening stimuli. Individuals with elevated state anxiety measured via self-report demonstrate increased attentional orienting towards threatening stimuli and enhanced attentional capture by physically salient stimuli. However, such findings are limited to attentional mechanisms toward the threatening nature of a stimulus and do not extend to more systemic changes in attentional control when the observer is in a threatened state. It is yet unknown whether elevated state anxiety globally modulates attentional capture through a core mechanism or whether such changes in observer state uniquely modulate different modes of attentional control. Furthermore, the mechanism by which threatening stimuli are afforded greater attentional priority in individuals with elevated state anxiety is still unclear.
In this dissertation, I investigate how attentional priority can be modulated by changing the state of an individual by experimentally inducing anxiety through the Threat of Shock (ToS) paradigm. I first present a series of behavior experiments that investigate how unpredictable threat modulates the three predominant mechanisms of attentional selection: attentional capture by reward history (selection history), color (salience-driven), and strategic goals. Then, I present a neuroimaging experiment that investigates how the neural mechanisms of processing threat interacts with mechanisms of attentional selection by previously-reward associated stimuli. I conclude by expanding on the core findings of this dissertation and its implications concerning how changes in observer state modulates attentional control and how the identified mechanisms can be expanded to inform our understanding of attentional biases toward threatening stimuli. | en |
