Henson et al. [1996] conducted an experiment to see whether caffeine has a negative effect on short-term visual memory. High school students were randomly chosen: 9 from eighth grade, 10 from tenth grade, and 9 from twelfth grade. Each person was tested once after having caffeinated Coke, and once after having decaffeinated Coke. After each drink, the person was given ten seconds to try to memorize twenty small, common objects, then allowed a minute to write down as many as could be remembered. The main question of interest is whether people remembered more objects after the Coke without caffeine than after the Coke with caffeine.
caffeineA double matrix with 28 observations on the following 3 variables.
Grade of the Student, which is either 8th, 10th, or 12th
Number of items remembered after drinking Coke without Caffine
Number of items remembered after drinking Coke with Caffine
Claire Henson, Claire Rogers, and Nadia Reynolds. Always Coca-Cola. Technical report, University Laboratory High School, Urbana, IL, 1996.