Kruger, Tyler2024-08-162024-08-162024-08-162024-08-06https://hdl.handle.net/10012/20811Caffeine is a popular psychoactive substance used by a large part of the population primarily to increase their cognitive abilities. In this dissertation I explore the links between caffeine consumption, motives to use caffeine, and attention-related experiences. After reviewing the relevant literature (Chapter 1), I report several studies (Chapter 2) exploring 1) how caffeine consumption relates to attention in everyday life using self-report measures that each target a different facet of attentional engagement, and 2) how different motivations for choosing to ingest caffeine may relate to the measures of everyday attention. Findings showed that amount of caffeine consumed in a typical day (estimated in milligrams) was not to related to attention-related experiences in everyday life. However, those who are more likely to ingest caffeine to potentially enhance their cognition, or to experience the reinforcing effects of caffeine, or to help relieve negative affect showed higher levels of inattention in everyday life. Next, I explored how caffeine (versus placebo) may influence performance and attentional engagement during a sustained auditory attention task, as well as the replicability of earlier findings regarding the effects of caffeine consumption on various attention-related experiences such as affect, arousal, boredom, sleepiness, and mental effort (Chapter 3). Participants completed two sessions of an attention task (once before consuming caffeine or placebo and once after) and intermittently responded to thought probes asking about their mind-wandering. Compared to placebo, findings showed that there was a performance and attentional benefit on the attention task following caffeine consumption. I also replicated earlier findings by showing that participants who consumed caffeine reported greater positive affect and arousal as well as less feelings of boredom, sleepiness, and mental effort compared to placebo. I also further explored the positive relation regarding the cognitive motives of caffeine consumption and the tendency to experience more inattention in everyday life. Prior to caffeine consumption, participants who had greater cognitive motives reported being less on task; following caffeination, this correlation became non-significant. In a follow-up study (Chapter 4), I sought to replicate the main findings from the attention task and further explored the relations between cognitive motives and proportion of on task responses in a larger sample. I replicated my earlier findings by showing there was a performance and attentional benefit on the attention task following caffeine consumption. I also replicated the findings regarding affect, arousal, boredom, sleepiness, and mental effort. Importantly, however, I failed to replicate the relations between the cognitive motives and proportion of on task responses suggesting that this relation may not be as robust as originally thought. Finally, I conclude (Chapter 5) by contextualizing the main findings from the studies presented, their limitations, and suggest future directions.encaffeineattentionmind-wanderingDoctoral Thesis