Do Individual Differences Moderate the Cognitive Benefits of Chewing Gum?

Recent experiments investigating whether chewing gum enhances cognitive performance have shown mixed re-sults and a recent replication failed to reproduce earlier findings. The present experiment aimed to investigate whether participant individual differences underlie the discrepant findings. Therefore, in addition to examining differences in Digit Span and Spatial Span performance across gum and control groups, chronotype, extraver-sion, habitual tiredness, current stress, current arousal and current thirst were assessed using questionnaires. Task difficulty was also manipulated. While there were no chewing gum effects under standard testing condi-tions, chewing gum enhanced Digit Span performance in the more difficult dual task condition. Furthermore, Spatial Span performance was improved by chewing gum in introverts but not extraverts and chewing gum was shown to eliminate the negative relationship between thirst and Digit Span performance. In explaining these data it is proposed that chewing gum may act both to reduce stress and to alleviate thirst