Chewing and Concentration — What Does the Research Say?

Last updated: 12 April 2026 · Chewel

Research consistently shows that chewing has measurable effects on sustained attention, reaction time, and stress hormones. The effect is real but nuanced — it works best for people who are sensory seeking or under-aroused. Understanding the Yerkes-Dodson principle helps explain why chewing helps some people dramatically and has little effect on others.

The Research in Detail

Hirano et al. (2015) — Sustained Attention and Reaction Time

A study published in Brain & Cognition investigated the effects of chewing on cognitive processing speed. Participants performed a sustained attention task under three conditions: chewing, not chewing, and a control. The chewing condition produced:

• Significantly faster reaction times
• Fewer errors on a sustained attention task
• Increased activity in brain regions associated with attention (observed via neuroimaging)

The researchers concluded that chewing appears to increase cerebral blood flow and activate neural networks associated with attention and working memory. The effect was most pronounced during the later part of the sustained attention task — consistent with chewing providing a counter to the attention decrements that occur with time-on-task.

Miquel et al. (2019) — Meta-Analysis of 15 Studies

This systematic review and meta-analysis examined 15 randomised controlled trials (RCTs) investigating the effect of chewing gum on cognitive function and mood. The analysis found:

• Statistically significant positive effects on attention across studies
• Positive effects on episodic memory (remembering specific events)
• Positive effects on mood (reduced anxiety, improved alertness)
• Effects were larger in longer studies, suggesting cumulative benefit over time

The researchers noted that the effects are "modest but consistent" — they are not dramatic cognitive enhancements, but they are real and reproducible. The meta-analysis gives us more confidence in the findings than any single study could.

Yaman-Sözbir et al. (2019) — Exam Stress and Performance

This study examined university students during examination periods — one of the most stressful academic experiences. Students who chewed gum during exams showed:

• Significantly lower salivary cortisol levels (cortisol is the primary stress hormone)
• Lower self-reported anxiety
• Higher examination scores

This is a particularly compelling finding for practical application. Chewing during exams appears not only to reduce stress but to translate that reduction into measurable performance improvements.

The Yerkes-Dodson Explanation

The Yerkes-Dodson law (Yerkes & Dodson, 1908) describes the relationship between arousal and performance as an inverted U-curve. At very low arousal (drowsy, bored), performance is poor. At very high arousal (anxious, overwhelmed), performance is also poor. Performance peaks at a moderate, optimal arousal level.

Different people have different "set points" — their natural resting arousal level. People with ADHD often have a lower resting arousal level, which means they need more stimulation to reach the optimal zone. People who are anxious or overwhelmed are at the upper end of the curve and need calming input to return to optimal.

Chewing is unusual in that it appears to work bidirectionally: it can increase arousal in under-aroused individuals (by providing stimulating input) and reduce it in over-aroused individuals (via vagal nerve activation and the calming effects of rhythmic jaw movement). This bidirectional effect is consistent with what occupational therapists observe clinically — proprioceptive input from the jaw tends to bring people toward, not away from, their optimal arousal level.

Who Benefits Most?

The research effects are most pronounced in:

• People who are sensory seeking — actively looking for oral input
• People in situations of elevated stress (exams, presentations, cognitively demanding tasks)
• People with ADHD, who tend toward under-arousal and need additional stimulation
• People who are already chewing something else (nails, clothing, pen lids) — a chew necklace gives them a better outlet for the same need

For someone who is already well-regulated, calm, and focused, adding chewing is unlikely to produce a dramatic additional benefit. Chewing is not a universal cognitive enhancer — it is a sensory regulation tool that works best when there is a sensory regulation need.