Two cups of coffee to improve text reading abilities, semantic association and to make activities more fun

The psychostimulant effects of caffeine have been investigated through numerous studies that have shown improvement in global perception of stimuli, typically associated with the right brain hemisphere. To investigate the cognitive and psychophysiological effects of caffeine, we involved a sample of 54 healthy young adults in a crossover double-blind, randomized placebo- controlled trial. We supposed that 200mg of caffeine could improve reading and semantic abilities in connection with an improvement of positive emotion. We administered caffeine or a placebo to the participants and invited them to play a board game for 25 minutes. At the end of the game session, we asked them to evaluate the game and their activation state. Then, we administered text reading and semantic association tasks. Our study shows an improvement in reading speed and in the ability to find semantic associations between words following the administration of a single dose of caffeine. Even more interesting is the effect on heart rate variability and perceived emotion: participants report that the same game activities performed during the two experimental sessions are more fun only after caffeine intake. These effects are not related to sleep deprivation or other types of self-perceived psychophysiological activation.