Date of Award


Document Type


Degree Name

Master of Science (MS) in Psychology: General/Experimental



First Advisor

Jonathan Anderson

Second Advisor

Amani El-Alayli

Third Advisor

Doris Munson


The purpose of this study was to investigate the effect of caffeine on several components of time perception in an attention-demanding task. Review of the current literature shows that the rhythm of the brain's internal clock, controlled by the suprachiasmatic nucleus (SCN), which is believed to mediate the perception of short durations, is sensitive to a variety of stimuli including stimulants. This study expands on previous research on the effect of caffeine on prospective time estimation by having participants estimate multiple short durations while completing a cognitively complex time estimation task involving math. The study included a moderate dose caffeine condition and a placebo condition. Previous findings have shown that a moderate dose of caffeine, coupled with a relatively complex information-processing task, limits individuals’ ability to allocate cognitive resources necessary for accessing the internal clock (Gruber & Block, 2005). It was hypothesized that with a more complex cognitive task, participants given caffeine would make shorter temporal predictions than those given a placebo. Contrary to expectations, the results suggest that a 200mg dose of caffeine does not have an impact on an individual’s ability to accurately estimate short durations of time while completing an attention-demanding task. Limitations to these findings are discussed and although the results were counter to the hypotheses, they help to provide scaffolding for future research investigating similar effects of caffeine on the ability to accurately estimate durations of time.