Recent evidence has indicated that chewing gum can enhance attention, as well as promoting well-being and work performance. Four studies (two experiments and two intervention studies) examined the robustness of and mechanisms for these effects. Study 1 investigated the acute effect of gum on mood in the absence of task performance. Study 2 examined the effect of rate and force of chewing on mood and attention performance. Study 3 assessed the effects of chewing gum during one working day on well-being and performance, as well as postwork mood and cognitive performance. In Study 4, performance and well-being were reported throughout the workday and at the end of the day, and heart rate and cortisol were measured. Under experimental conditions, gum was associated with higher alertness regardless of whether performance tasks were completed and altered sustained attention. Rate of chewing and subjective force of chewing did not alter mood but had some limited effects on attention. Chewing gum during the workday was associated with higher productivity and fewer cognitive problems, raised cortisol levels in the morning, and did not affect heart rate. The results emphasise that chewing gum can attenuate reductions in alertness, suggesting that chewing gum enhances worker performance.
Chewing gum can enhance alertness and sustained attention, although its effects upon stress may differ depending upon whether chronic or acute stress is examined; see reviews by Allen and Smith [
Consistent with an alerting effect of chewing gum under laboratory conditions, chewing gum during the workday has also been shown to enhance self-reported productivity both in university staff [
People who chew gum habitually report less stress [
The current research aims to examine the effect of gum on well-being and cognitive performance by combining the study of chewing effects under controlled conditions with a more naturalistic examination of chewing gum during the workday. We firstly examined the acute effect of chewing gum on mood in the absence of cognitive performance (Study 1: Mood Effects in the Absence of Performance). Although previous research on mood effects of gum has examined chewing in the absence of cognitive performance, this has been in the context of sleep deprivation [
All studies described in this paper received ethical approval from Cardiff University’s School of Psychology Ethics Committee and were conducted in accordance with the Declaration of Helsinki.
One hundred adults (81 females, 19 males; mean age = 21.1, SD = 3.6) were recruited. Participants were mostly students from the School of Psychology, Cardiff University. For all studies, people taking medication, who reported medical problems, who consumed more than 40 units of alcohol per week, or who smoked more than 10 cigarettes in the daytime and evening, were excluded from participation. Participants were recruited through a university notice board and an online experiment management system.
Participants were assigned at random to one of four conditions: chewing spearmint gum with replacement of gum (female = 20, male = 5), chewing gum without replacement (female = 22, male = 3), chewing gum base (female = 21, male = 4), and no chewing (female = 18, male = 6).
Testing was scheduled for between 10.00 and 12.00. Participants filled in questionnaires assessing demographic information and habitual gum consumption on arrival. They were then provided with two pieces of spearmint gum or gum base if they were in a chewing condition and told to chew constantly throughout the procedure. Immediately after starting to chew gum they completed the initial mood assessment tasks. They were then requested to sit quietly and continue chewing. After 15 minutes, participants in a chewing condition were verbally reminded to continue chewing, and those in the replacement condition were reminded to replace the gum with two new pellets if the current gum had lost its flavour. Psychology textbooks and journals were available for participants to read, and participants could bring their own reading material. After 25 minutes, the participants filled in the final mood assessment task.
This analysis was conducted in two stages, with the first stage testing the effect of chewing gum per se, by comparing the no-gum control to the three gum conditions combined, using 2 × 2 mixed ANOVA, with the independent variables being time (initial and final assessment) and chewing (chewing versus no chewing). The second stage evaluated differences between all four gum conditions, using 2 × 4 mixed ANOVA, with the independent variable being time (as above) and gum condition (spearmint with replacement, spearmint gum without replacement, gum base, and no-gum control). The dependent variables were alertness, hedonic tone, and anxiety.
Alertness fell significantly between the initial and final assessment,
Averaging across gum conditions, alertness was higher in chewing gum conditions compared to the control,
Chewing gum and initial and final mood (Study 1). (a) Alertness. (b) Hedonic tone. (c) Anxiety (S = spearmint gum without replacement, S/R = spearmint gum with replacement, GB = gum base, and N = no-gum control). Error bars represent standard error of the mean.
Comparing the no-gum control to all gum conditions, there was a trend for gum to increase hedonic tone,
Comparing the no-gum control to all gum conditions, gum did not have a main effect on anxiety,
Consistent with multiple studies examining chewing gum during cognitive performance, the results of Study 1 indicate that chewing gum may increase alertness in the absence of cognitive performance tasks. There was also a trend for hedonic tone to be increased by chewing gum. However, in the absence of cognitive performance tasks anxiety was not affected by chewing gum. The observed alerting effect was not dependent upon mint flavor; it may be the case that chewing plays a key role in such an alerting effect. It is thus of interest if the rate of chewing may moderate alerting effects of gum.
This experiment examined if rate of chewing could potentially moderate the effects of gum on attention and mood. Participants were filmed while chewing in order to establish the rate of chewing (pilot data indicated good interrater reliability for scoring of number of chews per minute).
Fifty-six adults (42 females, 14 males; mean age = 19.6, SD = 1.4) were recruited. Participants were mostly students from the School of Psychology, Cardiff University.
Mean reaction time, number of errors, and number of long responses (>800 ms) were measured. The threshold for long responses was based on previous research [
Mean reaction time, accuracy, and long responses (>1000 ms) were recorded, as well as reaction time and accuracy with which new information was encoded. Differences in reaction time and accuracy for trials where the position of the target stimulus and response key were compatible versus where they were incompatible were used as a measure of response organisation. The effect of the stimulus appearing in a different location versus the same location as the previous trial was measured, as well as the effect of not knowing the location of the target. This task also lasted approximately 5 minutes.
Each participant completed both the chewing gum and no-gum control conditions. Similar to previous studies, gum condition was included as a crossover variable to test if any effects of gum would carry over to a no-gum condition (for those who completed the gum condition first).
Following informed consent and a familiarisation with the mood and attention tasks, participants completed the mood and attention tasks twice. Participants were instructed to chew two pieces of gum constantly at their own pace during one of these testing sessions and not to chew during the other testing session. Each set of the mood and attention tasks took approximately 25 minutes, and participants completed the second condition immediately after the first. Participants selected a packet of gum just before the chewing condition. They were filmed throughout the chewing session. In order to assess the rate of chewing during each task, notes were taken of when each computerised task began and ended. This timing of the tasks was matched to the footage of the participant completing the task, so that the rate of chewing during each specific task could be calculated. Participants indicated how hard they had been chewing on a scale of 1 (as softly as possible) to 11 (as hard as possible) immediately after the gum condition.
Multiple regressions with forced entry were used to test if the predictors were associated with changes in attention and mood between gum and no-gum conditions. The predictors were rate of chewing, speed of chewing and intensity (how hard gum was chewed), and prior amount of chewing (total count of times chewed; this did not apply for pretest mood, when chewing had just begun).
There was a significant main effect of time and chewing gum on alertness; alertness fell between pre- and posttest assessments,
Chewing gum, pre- and posttest mood (Study 2). (a) Alertness. (b) Hedonic tone. (c) Anxiety. Error bars indicate standard error of the mean.
Hedonic tone fell significantly between pre- and posttest,
There was no significant effect of time on anxiety,
Chewing gum had a significant main effect on categoric search speed of encoding. There was a significant interaction between gum condition and time-on-task for repeated digits reaction time,
Time-on-task trends in chewing gum effects on (a) vigilance reaction time, (b) vigilance false alarms, (c) vigilance hits, and (d) categoric search reaction time (Study 2). Error bars represent standard error of the mean.
There was a gum by time-on-task interaction for false alarms,
For vigilance hits, there was no significant main effect of chewing gum,
There was a gum × time interaction for categoric search reaction time, with gum shortening reaction time, but only during the first block,
Gum had a significant main effect on focused attention speed of encoding, with slower encoding of information in the gum condition. There was a significant interaction between chewing gum and order of gum condition for focused attention mean reaction time, errors, speed of encoding, and simple reaction time. For simple reaction time, performance was improved by gum when it came after the control condition, while the opposite was true for focused attention. Results are summarised in Table
Chewing gum, time-on-task, and attention.
Gum | No gum | Results | |
---|---|---|---|
Focused attention | |||
Mean reaction time (ms) | Block 1: |
Block 1: |
Gum: |
Total errors | 10.18 (1.12) | 10.15 (1.04) | Gum: |
Long responses | .27 (.09) | .45 (.21) | Gum: |
Breadth of attention1 | 18.99 (4.71) | 25.83 (5.39) | Gum: |
Speed of encoding2 | 25.47 (2.77) | 24.44 (2.61) | Gum: |
|
|||
Categoric search | |||
Total errors | 11.16 (.8) | 11.84 (.93) | Gum: |
Long responses | 1.66 (.3) | 1.87 (.36) | Gum: |
Response organisation3 | 27.51 (2.54) | 26.88 (2.53) | Gum: |
Speed of encoding | 17.69 (2.73) | 4.77 (2.54) |
|
Spatial uncertainty4 | 105.92 (4.83) | 116.26 (5.34) | Gum: |
Place repetition5 | 15.62 (2.56) | 14 (2.92) | Gum: |
|
|||
Simple reaction time | Block 1: |
Block 1: |
Gum: |
Standard errors of the means are in parentheses. 1Higher score = broader focus of attention. 2Higher score = slower encoding of information. 3Higher score = poorer organisation. 4Higher score = greater uncertainty. 5Higher score = greater effect of place repetition. **indicates
A faster rate of chewing was associated with lengthened simple reaction time (beta = .42,
Level of chewing and its effect on mood and cognition.
Unstandardised |
SE |
Beta | Significance |
|
Adjusted |
|
---|---|---|---|---|---|---|
Mood | ||||||
Pretest alertness | .03 | −.01 | ||||
Constant | 26.45 | 18.14 | .15 | |||
Rate of chewing | −.57 | .62 | −.13 | .36 | ||
Intensity | −1.04 | 2.65 | −.06 | .7 | ||
Posttest alertness | .06 | .01 | ||||
Constant | 20.74 | 13.08 | .12 | |||
Rate of chewing | −.9 | .6 | −.32 | .14 | ||
Prior chewing | .01 | .02 | .12 | .61 | ||
Intensity | 2.19 | 2.53 | .13 | .39 | ||
Pretest hedonic tone | .02 | −.02 | ||||
Constant | .56 | 9.77 | .95 | |||
Rate of chewing | −.25 | .33 | −.11 | .45 | ||
Intensity | 1.44 | 1.43 | .15 | .32 | ||
Posttest hedonic tone | .04 | −.02 | ||||
Constant | 11.67 | 7.37 | .12 | |||
Rate of chewing | −.41 | .34 | −.26 | .23 | ||
Prior chewing | .004 | .01 | .11 | .47 | ||
Intensity | −.33 | 1.43 | −.04 | .82 | ||
Pretest anxiety | .05 | .01 | ||||
Constant | −9.62 | −.01 | .11 | |||
Rate of chewing | −.006 | .2 | −.01 | .98 | ||
Intensity | 1.31 | .85 | .22 | .13 | ||
Posttest anxiety | .02 | −.04 | ||||
Constant | .2 | 4.07 | .96 | |||
Rate of chewing | −.09 | .19 | −.11 | .62 | ||
Prior chewing | −.001 | .005 | −.04 | .86 | ||
Intensity | .29 | .79 | .06 | .71 | ||
Focused attention | ||||||
Mean reaction time (ms) | .02 | −.04 | ||||
Constant | .8 | 8.93 | .93 | |||
Rate of chewing | .25 | .29 | .14 | .39 | ||
Prior chewing | −.003 | .01 | −.04 | .81 | ||
Intensity | −1.01 | 1.78 | −.09 | .57 | ||
Total errors | .1 | .05 | ||||
Constant | −1.6 | 2.09 | .45 | |||
Rate of chewing | .02 | .07 | .04 | .81 | ||
Prior chewing* | .01 | .003 | .32 | .04 | ||
Intensity | −.15 | .42 | −.05 | .72 | ||
Number of long responses | .02 | −.03 | ||||
Constant | .1 | .58 | .86 | |||
Rate of chewing | .01 | .02 | .04 | .81 | ||
Prior chewing | .001 | .001 | .12 | .46 | ||
Intensity | −.11 | .12 | −.15 | .34 | ||
Breadth of attention | .11 | .06 | ||||
Constant | −47.15 | 19.44 | .02 | |||
Rate of chewing | 1.01 | .63 | .27 | .09 | ||
Prior chewing | −.02 | .03 | −.12 | .46 | ||
Intensity | 4.3 | 3.87 | .17 | .27 | ||
Speed of encoding | .03 | −.03 | ||||
Constant | −6.53 | 7.38 | .38 | |||
Rate of chewing | .13 | .24 | .09 | .58 | ||
Prior chewing | .003 | .01 | .04 | .79 | ||
Intensity | .69 | 1.47 | .07 | .64 | ||
Categoric search | ||||||
Mean reaction time | .01 | −.05 | ||||
Constant | −1.86 | 12.14 | .88 | |||
Rate of chewing | .01 | .44 | .002 | .99 | ||
Prior chewing | .004 | .02 | .04 | .83 | ||
Intensity | −1.49 | 2.42 | −.1 | .54 | ||
Total errors | .03 | −.03 | ||||
Constant | −2.12 | 1.72 | .23 | |||
Rate of chewing | −.01 | .06 | −.04 | .83 | ||
Prior chewing | −.001 | .002 | −.07 | .72 | ||
Intensity | .42 | .34 | .19 | .23 | ||
Long responses | .11 | .06 | ||||
Constant | 1.84 | .88 | .04 | |||
Rate of chewing | −.04 | .03 | −.22 | .2 | ||
Prior chewing | <.001 | .001 | .06 | .73 | ||
Intensity | −.26 | .18 | −.23 | .14 | ||
Response organization | .01 | −.05 | ||||
Constant | 1.43 | 8.79 | .87 | |||
Rate of chewing | .21 | .32 | .12 | .52 | ||
Prior chewing | −.003 | .01 | −.05 | .8 | ||
Intensity | −.7 | 1.75 | −.06 | .69 | ||
Speed of encoding | .11 | .05 | ||||
Constant | 29.75 | 9.82 | .004 | |||
Rate of chewing | −.03 | .36 | −.02 | .93 | ||
Prior chewing | .02 | .01 | .21 | .24 | ||
Intensity* | −4.74 | 1.96 | −.37 | .02 | ||
Spatial uncertainty | .05 | −.004 | ||||
Constant | −15.94 | 16.94 | .35 | |||
Rate of chewing | −.88 | .61 | −.25 | .16 | ||
Prior chewing | .01 | .02 | .09 | .63 | ||
Intensity | 3.56 | 3.38 | .16 | .3 | ||
Place repetition | .02 | −.03 | ||||
Constant | −2.41 | 8.23 | .77 | |||
Rate of chewing | −.1 | .3 | −.06 | .73 | ||
Prior chewing | .01 | .01 | .18 | .35 | ||
Intensity | .09 | 1.64 | .009 | .95 | ||
Simple reaction time | .08 | .03 | ||||
Constant | −21.09 | 15.47 | .18 | |||
Rate of chewing* | .84 | .49 | .42 | .04 | ||
Prior chewing | .007 | .02 | .05 | .7 | ||
Intensity | .74 | 2.69 | .04 | .79 | ||
Repeated digits vigilance | ||||||
Percent hits | .09 | .04 | ||||
Constant | 1.41 | 1.79 | .44 | |||
Rate of chewing | −.11 | .05 | −.32 | .06 | ||
Prior chewing | <.001 | .002 | −.03 | .86 | ||
Intensity | .27 | .33 | .12 | .42 | ||
False alarms | .04 | −.01 | ||||
Constant | −.73 | 5.31 | .89 | |||
Rate of chewing | .17 | .16 | .17 | .31 | ||
Prior chewing | .002 | .006 | .06 | .69 | ||
Intensity | −1.11 | .98 | −.18 | .26 | ||
Reaction time | .06 | .007 | ||||
Constant | −17.49 | 24.72 | .48 | |||
Rate of chewing | −1.2 | .75 | −.27 | .12 | ||
Prior chewing | .02 | .03 | .12 | .41 | ||
Intensity | 6.89 | 4.56 | .23 | .14 |
Consistent with previous research as well as Study 1, chewing gum was associated with higher alertness. This might be expected to improve sustained attention performance, although the results indicated lengthened reaction time as well as fewer false alarms as the vigilance task continued, suggesting negative and positive effects on sustained attention performance. Vigilance performance was not moderated by rate of chewing; however, although faster chewing was associated with lengthened simple reaction time, harder chewing was associated with faster encoding of new information on the categoric search task, and prior chewing was associated with more errors on the focused attention task. It thus may be useful for researchers to take some measure of how hard and fast participants are chewing in future research.
In order to further examine the effects of chewing gum on performance and reported feelings in a more naturalistic setting, the next studies examined chewing gum over the course of a working day.
This study examined the effects of chewing gum over a single workday on reported well-being and performance. We hypothesised that chewing gum would be associated with improved well-being and performance at work.
One hundred and twenty-six adults (87 females, 39 males) were recruited. Mean age was 29 (SD = 6.7). Participants were full-time university staff; their occupations were administration/secretary (
Chewing gum was the same as used in Study 2.
The study comprised a one-day intervention; participants were randomly assigned to a chewing condition (female = 39, male = 23) or nonchewing condition (female = 48, male = 16).
During an initial study visit before the main testing day, participants completed a familiarisation with the tasks performed on the PC and completed a questionnaire concerning general levels of well-being and performance at work (these acted as baseline scores of well-being and performance). Participants also provided information about demographics, occupation, and habitual level of chewing gum. On the testing day, participants completed a full battery of the mood and attention tasks in the morning as baseline measures. They were required to chew gum (one full packet of 10 pieces) or avoid chewing gum over the course of the working day. Participants were informed that they could chew when they wished during the working day, although they were encouraged to chew when they felt stressed, and they were told to eat and drink as much as they usually would. They returned to the laboratory following work and completed the same well-being questionnaire as in the familiarisation, except this time pertaining to how they felt that workday. They then completed the full battery again, to assess the effects of gum chewing during the workday; no one chewed gum during this battery.
Analyses of covariance were used, with chewing gum condition as the predictor, baseline scores as covariates, and well-being and performance as dependent variables.
Chewing gum was associated with reduced occupational stress,
Well-being and performance at baseline and following one-day chewing gum intervention/no-gum control.
Baseline | Intervention | |||
---|---|---|---|---|
Chewing gum | No gum | Chewing gum | No gum | |
Job stress | 1.44 (.1) | 1.48 (.07) | 1.08 (.12)* | 1.42 (.11) |
Fatigue | 2.39 (.12) | 2.26 (.11) | 2.18 (.14)* | 2.33 (.12) |
Anxiety | 5.08 (.35) | 4.63 (.29) | 3.03 (.3) | 2.61 (.29) |
Depression | 2.72 (.28) | 2.12 (.24) | 2.42 (.28) | 1.97 (.23) |
Inattention | 2.17 (.17) | 2.32 (.18) | 2.05 (.2)* | 2.52 (.21) |
Behind with work | 2.31 (.1) | 2.48 (.11) | 1.35 (.13)** | 1.84 (.13) |
Cognitive problems | 1.97 (.12) | 1.98 (.11) | 1.01 (.11) |
1.39 (.12) |
Standard errors of the means are in parentheses. Significant effects of gum intervention compared to no-gum, adjusting for baseline scores: *indicates
The results indicated that, similar to a previous intervention using the same measures but lasting for two weeks [
In this study we examined the effects of chewing gum on well-being and performance as well as heart rate and cortisol over the course of a working day. We hypothesised that chewing gum would reduce cortisol, consistent with a reduction in stress, and increase heart rate, consistent with findings of improved performance.
These were thirty full-time university staff (23 females, 7 males). Mean age was 30.4 (SD = 6.9). Their occupations were administration/secretary (
Chewing gum as well as mood and well-being measures was the same as those used in Studies 2 and 3. Heart rate was measured using Polar s610 heart rate monitors with Spectra 360 gel. Saliva samples were collected using Sarstedt salivettes.
Participants completed both chewing and no-gum control conditions in a crossover design.
During a familiarisation day, participants spent a workday wearing a heart rate monitor, giving saliva samples and recording well-being and performance at the same time as they did during the main testing days. The main testing took place over two separate days. Chewing gum was consumed during one testing day and avoided during the other, control day. The testing days were at least one week apart, in order to avoid carryover effects. Participants came into the lab before work (between 8 a.m. and 9.30 a.m.) to collect heart rate monitors, salivettes, gum (in the gum condition), and questionnaires (if using hard copies).
Participants were requested to chew a full packet of gum during the intervention day. Participants were emailed online links or given hard copies of questionnaires, which were filled in at 10.00, 11.00, 12.00, 14.00, and 15.00. Participants were free to chew gum before filling in the first questionnaire at 10.00. Saliva samples were taken at the same time as the questionnaires. Heart rate was measured throughout the working day.
Participants were requested not to eat for one hour before the postwork session. After work, well-being and performance were assessed again. Participants were instructed to keep saliva samples refrigerated after being taken. Saliva samples were frozen in a −20 freezer on return to the laboratory.
There was a trend for work done reported during the day to be higher in the gum condition,
Mean change between gum and control conditions in well-being and performance during the workday.
10 a.m. | 11 a.m. | 12 noon | 2 p.m. | 3 p.m. | Results | |
---|---|---|---|---|---|---|
Cognitive problems | −.03 (.13) | −.03 (.18) | −.27 (.2) | −.11 (.17) | −.41 (.22) | Gum: |
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Job stress | 0 (.25) | −.07 (.25) | −.17 (.17) | −.32 (.21) | −.24 (.18) | Gum: |
|
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Fatigue | −.16 (.32) | −.24 (.36) | −.25 (.39) | −.9 (.4) | −.81 (.45) | Gum: |
|
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Anxiety | 0 (.21) | 0 (.16) | −.4 (.17) | −.07 (.1) | .07 (.16) | Gum: |
|
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Depression | .13 (.14) | .18 (.13) | −.03 (.14) | .07 (.09) | .14 (.15) | Gum: |
Standard errors of the means are in parentheses.
Change between gum conditions in work done (being behind with work) during working day (Study 4). Lower difference scores indicate higher productivity in the gum condition compared to no-gum control. Error bars represent standard error of the mean.
At the end of the workday, reporting of cognitive problems was lower in the gum condition than in the control. The gum intervention reduced anxiety and inattention/hyperactivity reported at the end of the day, although these effects were not significant. The effects of chewing gum reported at the end of the intervention conditions are summarised in Table
Mean change between gum and control conditions in well-being and performance reported at the end of the workday.
Behind with work | −.13 (.21) |
|
Cognitive problems* | −.35 (.15) |
|
Job stress | −.12 (.12) |
|
Fatigue | .02 (.11) |
|
Anxiety | −.49 (.36) |
|
Depression | .25 (.35) |
|
Inattention | −.37 (.25) |
|
Change between gum conditions in heart rate over course of working day (Study 4). Higher difference scores indicate higher heart rate in the gum condition compared to no-gum control. Error bars represent standard error of the mean.
Change between gum conditions in cortisol over course of working day (Study 4). Error bars represent standard error of the mean.
Similar to Study 3, chewing gum was associated with reduced reporting of cognitive problems, along with a trend for being less behind with work, although we did not observe a positive effect on fatigue, inattention, or job stress in the current study, suggesting that over a one-day intervention the effect of chewing gum is more robust for performance than for well-being. There was some preliminary evidence that cortisol was increased in the morning, although heart rate was not significantly enhanced by chewing gum.
This research offers further evidence in support of an alerting effect of chewing gum, which was associated with heightened alertness both with and without cognitive performance. Although it is a possibility that those in chewing gum condition were coincidentally in a more alert state on entering the lab (which would be captured by a baseline mood measure) and that this carried over to the initial mood rating, there is previous evidence that chewing gum is associated with improved mood rated just after receiving gum [
Under experimental conditions in Study 2, chewing gum had varying effects on sustained attention performance, with lengthened reaction time in the fourth minute but fewer false alarms during the final minute. This is consistent with previous evidence, which has suggested generally positive but sometimes mixed effects of gum on attention [
Chewing gum during the working day was associated with reduced cognitive problems and enhanced productivity in both Study 3 and Study 4, suggesting that the experimental findings on sustained attention may generalise to the working environment. Similar to the experimental work of Smith [
Chewing gum reduced stress in Study 3, but not in Study 4, and in contrast to previous research, such as that of Smith et al. [
There are a number of other different mechanisms which could explain the observed effects of chewing gum, such as facial muscle activation [
Similar to a number of previous studies on the effects of chewing gum on cognition and mood [
Future research in this area could assess the psychophysiological effects of chewing gum in more depth; indices of heart rate variability and ambulatory blood pressure have been associated with work stress [
Chewing gum was associated with enhanced productivity and reduced cognitive errors at work, as well as heightened cortisol in the morning. However, rate of chewing, flavor, or cognitive performance did not moderate the enhancement of alertness and changes in sustained attention by chewing gum, suggesting that greater motor activity does not exaggerate these effects.
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors acknowledge Dr. Benita Middleton for performing cortisol assays. The first author’s Ph.D. studies were supported by the Wrigley Science Institute.