The Effect of Tablet Size on Cognitive Performance Caffeine

Background: A capsule's physical design (e.g. shape, size, and color) affects individuals' perception of drug efficacy; that is, how well a drug is likely to work. The goal of this study is to assess the effects tablet size may have on participant's performance on cognitive testing since research has found differences between preparation methods. Method: 120 participants will be randomly assigned to one of four groups: 1) 90 mg caffeine with a 1 mm diameter sucrose pillule; 2) no caffeine with the small sucrose pillule; 3) 90 mg caffeine with a 5 mm sucrose pillule; 4) no caffeine with the large sucrose pillule. Participants will consume the designated placebo tablet with water (caffeinated or non-caffeinated); then, participants will provide weekly caffeine intake and complete the neutral portion of Velten's Mood Induction Procedure until 30 minutes have passed to allow for caffeine activation. Participants will complete the Stroop test, Trial Making Tests A and B, and the Rey Auditory Verbal Learning Test. Previous literature, as far as the author knows, relied on evaluating drug efficacy based on appearance alone. This study aims to assess if tablet size, due to placebo effect, alters participants' performance on cognitive tests after consuming caffeine.