Overview

​

Chewing gum is a gelato or resin like substance intended to be chewed in the mouth but not swallowed. The chewing action has long been thought to stimulate muscle activity and increase overall alertness, thus stimulating students working for long periods of time. The main areas considered in research are concentration for sustained periods, alertness, and working memory. An additional theory more recently has been using gum to reduce anxiety, which, as a side-effect, increases attention. The specific effects of chewing gum in these areas is mixed with some studies showing no effects, but many more showing small magnitude positive effects.

               Early theories around chewing gum started in 1939, with a paper that showed positive effects on attention (Hollingworth, 1939). While it was theorized to be because of the muscle activity of mastication, this was revisited and a similar study looking at foot-tapping showed the same positive effects (Freeman, 1940). Therefore, it was concluded the mechanical activity of motor activity itself was the cause of the effect, and not the chewing itself.

               Chewing gum seems to have a larger impact in long term, sustained attention, and possibly negative effects in short term (less than 10 minutes). Tucha and colleagues (2011) found no short term impact on chewing gum, but adult participants showed increased alertness over sustained periods. Reaction times for participants chewing gum on concentration tasks were significantly better once the concentration task had been going for thirty minutes. This was also found in children by Tanzer and colleagues (2009). In Tanzer’s experiment, children chewing gum completed visual search tasks, and showed a disadvantage compared to children not chewing gum on performance, until the twelve minute mark, after which the gum chewing group outperformed the other children. However this study used a very small subset of children (2 per group). Participants have also been shown to make less mistakes in sustained attention tasks, during the second half of 8 minute concentration tasks (Yuda et al, 2018). This has also been shown on student performances in spelling tests, where students chewing for 5 and 10 minutes did not show an advantage (Wilson, Kim, & Raudenbush, 2016). However students chewing for 15 minutes did show a significant improvement in spelling test scores.

Gum has also been considered to boost alertness. This has been shown by many papers experimentally (e.g. Johnson et al, 2011). In another study, adult participants were given 10 minute and 20 min lessons on academic topics. Half the class was given gum to chew, and the adults chewing gum scored significantly higher on post-tests of lessons learned in both conditions (Ginns, Kim, & Zervos, 2019). In quick response Stroop test scores, participants showed higher alertness, measured by reaction times, but no increase in accuracy, when given chewing gum (Holling et al, 2018).  Related to alertness is the effects on working memory, which have been shown to be positively affected by chewing gum (Wilkinson, Scholey, & Wesnes, 2002). These positive effects of working memory have been replicated by showing increased performance on N-back tasks while under fMRI scans (Hirano et al, 2008). Participants in Hirano and colleagues 2008 study that were chewing gum while completing the N-back memory task showed increased activation in the right premotor cortex, precuneus, thalamus, hippocampus and inferior parietal lobe compared to not chewing gum. Given that several of these areas are directly related to memory and not directly related to motor activation (e.g. hippocampus, Squire & Knowlton, 1995)

A meta-analysis was conducted reviewing twenty-one different studies on sustained attention and alertness in gum chewing (Miquel, Haddou, & Day, 2019). When reviewing all papers, some of which showed negative effects, the meta review found weak, but significant, overall positive effects for gum chewing. The mean effect size (Cohen’s d) for sustained attention was 0.14 (weak, significant) and the mean effect size for alertness was 0.38 (moderate, significant).  

               An additional area explored is the anxiety and stress mediating effects of gum chewing. Gum chewing has also shown to have impacts on anxiety and stress in and out of the workplace (Smith, Chaplin, and Wadsworth, 2012). Gum has been used as an intervention, where university professors experiencing high stress showed reduced stress after being put on a gum-chewing schedule. Scholey and colleagues examined different levels of stress on participants with and without gum, and found in all conditions, participants chewing gum showed lower self report levels of stress, as well was reduced concentrations of cortisol in saliva samples in young adults. This reduced stress based on gum was also shown by Smith and Woods (2012) in university students. Gum chewing has also shown to significantly reduce acute stress during exams in students compared to not chewing gum, in a larger, more recent study of 100 students (Yaman-Sozbir et al, 2019). Additionally, it’s been shown that people who are long-term gum chewers have significantly lower stress, albeit mildly so, compared to people who do not (Smith, 2009). However, other studies have not been able to replicate the reduced salivary cortisol and stress shown (e.g. Johnson et al, 2011). The reasoning for the differing results remains unclear, however it’s been speculated chewing gum works alongside other cognitive processes. For instance, Konno and colleagues (2020) used infrared brain imaging (NIRS) to show activation in the Prefrontal Cortex of the brain in participants chewing gum when exposed to stress. Participants not chewing gum showed less activation in the same area of the prefrontal cortex, which has in the past been associated with responsiveness to stress (Arnsten, 2009). Reactions by these participants was consistent with self-reported measures of reduced stress.

Pros

• Cheap

• Requires no training

• Effects have been shown with sugar-free gum, making it a healthy choice

• Evidence based positive effects on alertness, anxiety, and sustained attention

Cons

• Some papers show no impact or negative impacts

• Cognitive mechanism and underlying principles remain unclear, making it hard to generalize to different groups

• Can reduce performance in the short term (>5 minutes)

To Consider

• All of these effects reported are small differences in performance. Regardless of the positive or negative impact of gum-chewing, the magnitude of the impact on a person seeking to use this tool should be expected to be small as well, which has been repeatedly shown (Miquel, 2019). This technology is not recommended as an intervention or fix by itself.

• These papers consider non-sweetened gum to avoid affects of sucrose consumption.

• Some papers considered flavour effects of the gum as well; peppermint and cinnamon have both been shown to be positive effects (Holling et al, 2018; Wilson, Kim, & Raudenbush, 2016).