Evaluating the Role of Expectations in Response to Caffeine Consumption: An RCT

Profile of Mood States (POMS-2)- Volunteers rated a series of 65 mood-related adjectives with regard to how they were feeling right now on a scale of 0 (not at all) to 4 (extremely). The adjectives factor into six mood sub-scales: Tension-Anxiety; Depression-Dejection; Anger-Hostility; Vigor-Activity; Fatigue-Inertia; Confusion-Bewilderment and a Total Mood Disturbance score which aggregates the six sub-scales into a single variable. - from our publication. The minimum and maximum possible raw scores were: 0 and 40 for Tension-Anxiety, 0 and 52 for Depression-Dejection, 0 and 44 for Anger-Hostility, 0 and 36 for Vigor-Aactivity, 0 and 24 for Fatigue-Inertia, 0 and 40 for Confusion-Bewilderment, -36 and 200 for Total Mood Disturbance, and 0 and 24 for Friendliness. For Friendliness and Vigor-Activity, the more positively a person feels, the higher the score. For all other sub-scales and Total Mood Disturbance, the more negatively a person feels, the higher the score.

Time frame: 30 minutes post pill consumption

Population: Results are of raw data as presented in our publication

Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication

Time frame: 45 to 105 minutes post pill consumption

Population: One participant who received the caffeine pill had to use the restroom during the vigilance testing period and had to stop the test. Due to a technicality of the computer program, her data for the vigilance test was not available for analysis.

Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication

Time frame: 45 to 105 minutes post pill consumption

Population: One participant who received the caffeine pill had to use the restroom during the vigilance testing period and had to stop the test. Due to a technicality of the computer program, her data for the vigilance test was not available for analysis.

Scanning Visual Vigilance Test. This test assesses vigilance, ability to sustain attention during long, boring, continuous tasks that generate minimal cognitive load (Fine et al, 1994; Lieberman et al, 1998; 2002). The volunteer continuously scans a computer screen to detect an infrequent, difficult-to-detect stimulus that appears at random intervals and locations for 2 s. On average, a stimulus was presented once per minute. Upon detection of the stimulus, the volunteer pressed the space bar as rapidly as possible. Whether a stimulus was detected and time required for detection was recorded. Responses before or after stimulus occurrence were false alarms. The test lasted 60 minutes. - from our publication

Time frame: 45 to 105 minutes post pill consumption

Population: One participant who received the caffeine pill had to use the restroom during the vigilance testing period and had to stop the test. Due to a technicality of the computer program, her data for the vigilance test was not available for analysis.