The Effect of Tablet Size on Cognitive Performance Caffeine

• Stroop Color-and-Word test[ Time Frame: Within 90 minutes of receiving informed consent. Actual task time: approximately 2 minutes ]
  Measures processing speed. 100-item, time-trial task where participants must read the color of the ink instead of color names printed on the task paper as quickly as possible for 45 seconds. Scores are measured in the number of correct responses within the allotted time.
• Trail Making task B[ Time Frame: Within 90 minutes of receiving informed consent. Actual task time: approximately 3 minutes ]
  Measures processing speed. 25 item, time-trial task where participants must connect numbers and letters in order (e.g. 1-A-2-B, etc.) as quickly as possible. Scores are measured by the amount of time (in seconds) for participants to complete the task.
• Rey Auditory Verbal Learning test[ Time Frame: Within 90 minutes of receiving informed consent. Actual task time: approximately 40 minutes ]
  Measures memory. 30-item, 2 section task where participants are read 15 words and asked to recall as many words as possible in the first section. A second set of 15 words is then introduced and participants recall those. The second section consists of revisiting the original set of words and recalling as many of those. Scores are measured by the total words remembered in section one, and another score for the total intrusions from the second list into the recall of section two.

This study aims to assess if tablet size, due to placebo effect, alters participants' performance on cognitive tests after consuming caffeine. 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.

• Drug: Caffeine Anhydrous with small sucrose pill
  caffeine anhydrous that has been weighed out to 90 mg per dose presented with a 1 mm sucrose pillule
• Other: Placebo - large sucrose pill
  sucrose pillules of 5 mm diameter will be given to all participants in the large pill groups
• Drug: Caffeine Anhydrous with large sucrose pill
  caffeine anhydrous that has been weighed out to 90 mg per dose presented with a 5 mm sucrose pillule
• Other: Placebo - small sucrose pill
  sucrose pillules of 1 mm diameter will be given to all participants in the small pill groups

• Active Comparator: Caffeine with small sucrose pill
  Participants will be given one dose of 90 milligrams caffeine anhydrous dissolved in 8 ounces of water and a 1 mm sucrose pill to consume in 10 minutes. After 30 minutes post-administration, the cognitive tests will be administered.
• Active Comparator: Caffeine with large sucrose pill
  Participants will be given one dose of 90 milligrams caffeine anhydrous dissolved in 8 ounces of water and a 5 mm sucrose pill to consume in 10 minutes. After 30 minutes post-administration, the cognitive tests will be administered.
• Placebo Comparator: No caffeine with small sucrose pill
  Participants will be given 8 ounces of water and a 1 mm sucrose pill to consume in 10 minutes. After 30 minutes post-administration, the cognitive tests will be administered.
• Placebo Comparator: No caffeine with large sucrose pill
  Participants will be given 8 ounces of water and a 1 mm sucrose pill to consume in 10 minutes. After 30 minutes post-administration, the cognitive tests will be administered.