Effect of Caffeine on the Fixation Component of Eye Movement in the Reading Process

Background: Caffeine is a kind of methylxanthine whose consumption can promote the cognitive and executive functions of the human brain. Objectives: In this study, we seek to investigate the effect of drinking coffee on the period of the eye movement fixation component. Materials and Methods: The research was of the quasi-experimental type. 60 subjects were randomly divided into two groups of thirty. The subjects in one group drank coffee before the experiment was conducted. The other group, which is the control group, did not. Both groups would then read a text, and the eye movement tracking device would record the fixation periods of the subjects’ eyes while reading. Results: The results of the independent t-test comparing the mean fixation time in the two groups demonstrated that the difference was significant at the 0.001 level, where the group that drank coffee before studying had significantly less fixation time than the control group. Additionally, Cohen’s d index of 4.29 determined that the difference lies in the maximum effect size range. Conclusion: It can be concluded that drinking a cup of coffee before studying can lead to decrease in eye movement fixation period and increase in information encoding and processing speed.