According to studies, caffeine in combination with theanine has been shown to improve accuracy and alertness. Accuracy refers to the state of being correct or precise. In some studies, people who consumed caffeine and theanine had improved accuracy on an “attention switching task” – the ability to shift back and forth between different task sets – and reported increased alertness. In another study, people who consumed caffeine and theanine improved on a computer task that measured how accurately the participants responded to targets and did not respond to non-targets.
