Effects of chewing gum and time-on-task on alertness and attention

Rationale: Chewing gum has been shown to reliably increase subjective alertness whereas the effects on attention are more variable. It has been suggested that chewing gum only enhances attention when the person has been performing a task for some time. Objectives: The current research aimed to investigate if time-on-task trends enhancing effects of chewing gum could be observed in alertness and attention during and following chewing. Methods: Study 1 used tests of reported mood, including reported mood, and tests of attention (categoric search, focussed attention, simple reaction time, and vigilance). These tasks were performed shortly after the start of chewing. Study 2 examined effects of previous and current chewing on reported alertness and the attention tests. Results: Study 1 showed that chewing gum increased reported alertness and hedonic tone and improved performance on the categoric search task. Chewing gum maintained reported alertness across sessions in study 2. In the first experimental session of study 2 gum improved categoric search performance, and during the second session gum broadened focus of attention and quickened vigilance reaction time. This effect on vigilance reaction time was moderated by time-on-task, with an initial negative effect being replaced by a positive effect. Discussion: The results confirm the robust effect of chewing gum on reported alertness and show that changes in the effects of chewing gum on attention require further investigation. Future research may also determine underlying mechanisms for an alerting effect.