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Nutritional Neuroscience 2009 Vol 12 No 2 81
Effects of chewing gum on mood, learning,
memory and performance of an intelligence
test
Andrew Smith
Centre for Occupational and Health Psychology, School of Psychology, Cardiff University, Cardiff, UK
Rationale: Recent research suggests that chewing gum may increase alertness and lead to
changes in cognitive performance. The present study examined effects of chewing gum on these
functions within the context of a single study.
Objectives: This study had four main aims. The first was to examine whether chewing gum
improved learning and memory of information in a story.The second aim was to determine whether
chewing gum improved test performance on a validated intellectual task (the Alice Heim task). A
third aim was to determine whether chewing gum improved performance on short memory tasks
(immediate and delayed recall of a list of words, delayed recognition memory, retrieval from
semantic memory, and a working memory task). The final aim was to determine whether chewing
gum improved mood (alertness, calm and hedonic tone).
Subjects and methods: A cross-over design was used with gum and no-gum sessions being on
consecutive weeks. In each week, volunteers attended for two sessions, two days apart. The first
session assessed mood, immediate recall of information from a story and performance on short
memory tasks. The second session assessed mood, delayed recall of information from a story and
performance of an intelligence test (the Alice Heim test).
Results: There were no significant effects of chewing gum on any aspect of recall of the story.
Chewing gum improved the accuracy of performing the Alice Heim test which confirms the benefits
of gum on test performance seen in an earlier study. Chewing gum had no significant effect on the
short memory tasks. Chewing gum increased alertness at the end of the test session in both parts
of the study. This effect was in the region of a 10% increase and was highly significant (P< 0.001).
Conclusions: The results of this study showed that chewing gum increases alertness. In contrast,
no significant effects of chewing gum were observed in the memory tasks. Intellectual performance
was improved in the gum condition. Overall, the results suggest further research on the alerting
effects of chewing gum and possible improved test performance in these situations.
Keywords: chewing gum, learning and memory, intelligence test, alertness
Introduction
In 1939, Hollingworth1found that chewing gum
improved cognitive performance. Until recently, there
has been no further research on the effects of chewing
gum on cognitive function. This is rather surprising
given the anecdotal evidence suggesting that people
Research article
Correspondence to: Prof. Andrew Smith, Centre for Occupational and
Health Psychology, School of Psychology, Cardiff University, 63 Park
Place, Cardiff CF10 3AS, UK
Tel: +44 2920874757; Fax: +44 2920874758;
E-mail smithap@cardiff.ac.uk
Received 15 September 2008;
Revised manuscript accepted 31 December 2008
© W. S. Maney & Son Ltd 2009
DOI 10.1179/147683009X423247
often chew when they need to maintain concentration
(e.g. when driving) or when they feel they are under
stress. However, there have now been a number of
recent studies of the topic and these, plus unpublished
research from our laboratory and other groups, are
reviewed here.
Wilkinson et al.2carried out a study to compare the
effects of chewing gum with sham chewing and no
chewing (total sample size = 75, 25 per group). Heart
rate was found to increase in the chewing condition.
Chewing gum improved immediate and delayed recall
of a list of words and there was also some evidence of
improved working memory. Neither psychomotor
speed (e.g. simple reaction time) nor sustained
attention were influenced by chewing gum. Mood was
not measured in this study. The major problem with
this study was that no baseline measures were taken
prior to the test conditions; this means effects
attributed to gum conditions may reflect individual
differences.
Baker et al.3investigated effects of chewing gum on
learning and recall of a word list with chewing being at
either learning, recall or both (experiment 1:
gum–gum, n= 23; gum–no-gum, n= 20; no-
gum–gum, n= 20; no-gum–no–gum, n= 20). Chewing
gum at initial learning had a beneficial effect and a
switch between gum and no gum between learning and
recall led to poorer performance. In a second
experiment (n= 48), sucking the gum led to the same
effects as chewing it. Again, there was no baseline
session prior to the test conditions.
Tucha et al.4examined effects of chewing gum on a
range of measures investigating memory and attention
in two experiments. Each volunteer (n= 58 in both
studies) was tested in four conditions: no chewing,
sham chewing, chewing a piece of tasteless gum and
chewing spearmint gum. Chewing gum did not
improve memory but it did improve sustained
attention. In contrast, chewing gum reduced alertness
and flexibility. Chewing did not influence heart rate.
The authors concluded their results suggested that
claims that chewing gum improves cognition should
be treated with caution. This study also has
methodological problems. Effects of order of
conditions were not included in the analyses and this
may mask any effects of chewing gum. In addition, no
baseline measures were taken prior to the test sessions.
Stephens and Tunney5tested the view that chewing
increases heart rate which leads to an increased flow of
nutrients, such as glucose, to the brain. Volunteers (n=
30) carried out four conditions made by combining
gum/mint and glucose/water factors. Chewing gum
improved immediate and delayed recall and working
memory. Glucose produced similar improvements in
all but the delayed recall task. They interpreted their
findings in terms of chewing improving delivery of
glucose but also suggested that the motor activity of
chewing may increase adrenergic arousal. Again, there
were no baseline measures prior to testing and effects
of order of conditions were not included in the
analyses.
The results from the above studies have been
debated in a number of other articles. Essentially,
these papers discuss the criticisms of the experimental
designs outlined above and also suggest that sample
sizes may not have been enough to detect smaller
effects in some studies. They also focus on the possible
role of flavour as well as chewing. In addition, regular
chewing habit is considered a possible confounder
across studies. It has also been concluded that many of
the laboratory measures have limited ecological
validity and that future studies should examine the
effect of chewing gum on measures of cognition in
everyday settings such as the classroom or workplace.
Johnson and Miles6examined the prediction that
chewing gum at learning and/or recall facilitated
subsequent memory. They tested 96 volunteers who
were assigned to one of four groups (gum/no-gum at
learning; gum/no-gum at learning and recall). The
results showed that chewing at learning had a
detrimental effect upon recall. There was no evidence
of a context-dependent effect of chewing gum. These
findings contradict results obtained in an earlier study
with an identical design.3Miles and Johnson7reported
two experiments designed to re-examine effects of
chewing gum on learning and also context dependent
memory effects. The studies differed from Baker et al.3
in that they involved a within-subject design and a
sequential presentation of the words. No context-
dependent effect was apparent in the gum condition
although it was in the no-gum condition (i.e. recall
was best with no-gum at both learning and recall).
Results from the first experiment provided no support
for a beneficial effect of gum on word learning nor did
they suggest that gum can produce context-dependent
effects. The second experiment replicated these
findings and also showed that chewing gum had no
effect on delayed recall.
Johnson and Miles6found that significantly more
words were recalled in the no-gum learning condition.
No context-dependent effect was present in the gum
condition even though it was involved in the no-gum
condition (i.e. recall was best with no-gum at both
learning and recall). Johnson and Miles23 examined
the effects of chewing flavourless gum or mint-
flavoured strips on the learning and recall of a list of
82 Nutritional Neuroscience 2009 Vol 12 No 2
Smith Chewing gum and intelligence test
words. Again, no context-dependent effect was
observed in the gum condition but chewing gum did
improve recall of the words. Mint-flavour improved
learning of a list of words but, again, no context-
dependent memory effect was observed in the mint-
flavour condition. Overall, these findings show that
the effects of chewing gum on learning and recall of a
list of words are variable and further research is
needed to determine whether more robust effects of
chewing occur for other outcomes.
The studies above tell us little about effects of
chewing gum on mood. In two studies, Smith8,9
examined this issue. The first (n= 122) examined
effects of prior chewing of both caffeinated gum and
placebo gum on mood. Both gum conditions
increased ratings of alertness and hedonic tone at the
start of the test session. A second study9examined
effects of chewing gum during performance. The aims
of the study were to determine if: (i) chewing gum
improved mood and mental performance; (ii) chewing
gum had benefits in stressed individuals; and (iii)
chewing habit, type of gum and level of anxiety
modified the effects of gum. A total of 133 volunteers
completed the study. Approximately half were tested
in 75-dBA noise and the rest in quiet. Each volunteer
carried out a test session when they were chewing gum
and without gum, with order of gum conditions
counterbalanced across subjects. Baseline sessions
were conducted prior to each test session. Volunteers
were stratified on chewing habit and anxiety level.
Approximately half the volunteers were given mint
gum and half fruit gum. The volunteers rated their
mood at the start and end of each session and had
their heart rate monitored over the session. Saliva
samples were taken at the start and end of each
session to allow cortisol levels (good indicators of
alertness and stress) to be assayed. During the session,
volunteers carried out tasks measuring a range of
cognitive functions (aspects of memory, selective and
sustained attention, psychomotor speed and
accuracy).
The results showed that chewing gum was
associated with greater alertness and a more positive
mood. Reaction times were quicker in the gum
condition, and this effect became bigger as the task
became more difficult. Chewing gum also improved
selective and sustained attention (the volunteers
chewing gum sampled a wider visual field and were
less likely to have lapses of attention). Several of the
memory tasks showed impaired performance in the
gum condition. This may reflect the effects of
increased alertness or chewing interfering with sub-
vocal rehearsal. Chewing gum increased heart rate and
cortisol levels suggesting that it was having an
arousing effect.
Overall, the above results suggest that chewing gum
produces a number of benefits that are generally
observed and not context-dependent (i.e. they were
observed in both stressed and non-stressed
individuals, and did not depend on chewing habit or
flavour). Furthermore, the study had appropriate
statistical power and involved baseline measurements
prior to the test condition.
Like most areas, there have been a number of, as
yet, unpublished studies of behavioural effects of
chewing gum. Reports of some of these studies have
been made available to the author by the Wrigley
Science Institute. Three studies were conducted at
Beijing University to investigate effects of gum on
memory and learning. The first compared gum,
sucking a mint and nothing in a cross-over design (n=
43). There were no significant effects of conditions
and it was suggested that this reflected lack of
familiarity with the gum. The second study examined
immediate and delayed recall of information from a
story by 10–13-year-olds (parallel groups design: n=
43–57). Short-term recall was improved by chewing
gum at both learning and recall. Long-term recall was
not improved by gum. The final study looked at the
effects of chewing gum on maths and language tests.
No effects of gum were observed.
Research at a New York dental school examined
whether chewing gum during a lecture, laboratory
class and studying had an effect on learning. Chewing
gum resulted in better performance in a written
examination but not a practical examination.
Research in Germany has examined the effects of
chewing gum on concentration by examining
performance of school children over time. The results
showed that chewing gum improved performance at
the end of the test period, which supports the
improved sustained attention result reported by
Smith.9
In conclusion, the literature described above clearly
shows variable effects of gum. One could argue that
there is evidence from specific tasks but the problem is
that one can cite other studies that do not support
such claims (e.g. some studies support an effect of
chewing gum on memory for a list of words, others do
not). Indeed, the findings must be viewed within the
context of methodological problems outlined above.
The review of the existing studies suggests that there
may well be some benefits of chewing gum on mental
functioning. Future research must use a sound
experimental design and first clarify the type of
functions that are improved, then try and understand
Nutritional Neuroscience 2009 Vol 12 No 2 83
Smith Chewing gum and intelligence test
the underlying mechanisms and also study real-life
activities (e.g. effects of chewing gum on learning and
retrieval of educational material; effect of chewing
gum on simulated driving; effect of chewing gum on
efficiency at work). Results from two unpublished
studies suggest two areas of practical relevance that
require further investigation. A study at Beijing
University showed that chewing gum resulted in better
immediate recall of information from a story. Second,
the study carried out at New York University showed
that chewing gum resulted in better written
examination performance in dental students. The
main aim of the present study was to replicate these
effects using modified procedures suitable for use with
university students from a range of disciplines. In
addition, the study provides another opportunity to
examine the effects of chewing gum on basic memory
functions and reported alertness.
Subjects and methods
The experiment was sub-divided into two parts carried
out on consecutive weeks. These will be referred to as
parts 1 and 2.
PART 1
This study used a technique that has been employed to
study effects of changes in alertness (e.g. circadian
variation in alertness) on recall of information from a
story.10–12 These results show better long-term memory
when alertness is higher and this is largely due to an
increased focus on important information (i.e. the
themes of the story). In contrast, more unimportant
information is recalled when the material is learnt
when alertness is low. Chewing gum may be
considered to be alerting (both physiologically and in
terms of subjective reports) and one can predict that
this will lead to better memory for important
information. The present technique has the advantage
of allowing the effects of chewing at learning and
recall to be compared and it allows one to look at
immediate recall and delayed recall (2 days later). In
addition, interpolated tasks are required in between
learning the story and short-term test and these were
short memory tasks used in previous studies of the
effects of gum. This allows comparison of different
effects of gum within the same study.
Design
A cross-over design was used with each volunteer
being tested in gum and no-gum conditions in a
counterbalanced order. One group (n= 40) chewed
gum at both learning and test. Another group (n= 40)
only chewed gum at learning and the final group only
chewed gum at test.
Summary of design
The design of the study is summarised in Table 1.
Sample size
Sample size considerations are complicated in this
type of study where one is considering multiple
outcome measures and using different parts of the
database to address different hypotheses. In general, it
is important to have sample sizes that will be able to
detect significant effects in the region of 0.5 SD. In the
case of gum and memory, one is making a within-
subject comparison. For such sample size calculations,
one needs to know the standard deviation of the
difference scores of gum and no-gum conditions. With
n= 64, power set to 0.8 and P< 0.05, then one should
be able to detect an effect size of 0.35 SD. The chosen
sample size was actually 120 which provides
additional power for the study.
Another way of assessing sample size is to look at
those in previous studies using this technique.
Oakhill12 demonstrated time-of-day effects with a
parallel groups design and a total of n= 64. Similarly,
the Beijing study showed effects of chewing gum on
story recall with parallel groups of 40–50. These all
suggest that a cross-over design with a total of n= 120
should be powerful enough to detect such effects.
Ethical approval
The study was carried out with the approval of the
ethics committee (School of Psychology, Cardiff
University) and with the informed consent of the
volunteers.
Procedure
Volunteers were familiarised with the procedure and
then completed the gum and no-gum conditions on
separate weeks (order of conditions counterbalanced
across volunteers). On the first day, volunteers rated
84 Nutritional Neuroscience 2009 Vol 12 No 2
Smith Chewing gum and intelligence test
Table 1 The design of the study
Group Week 1 Week 2
1 Gum, learning and recall (n = 20) No-gum
2 Gum learning (n = 20) No-gum
3 Gum recall (n = 20) No-gum
4 No-gum (n = 20) Gum learning
and recall
5 No-gum (n = 20) Gum learning
6 No-gum (n = 20) Gum recall
their mood and then read a short story (which took
about 10 min). Following this, they carried out the
short memory tests (20 min). Their recall of the story
was then tested using questions designed to cover the
themes of the story and specific details. This took
about 5 min. Mood was then assessed again. Two days
later, volunteers attended for another session and their
mood recorded and delayed recall for material presented
in the story tested. In the rest of this session volunteers
carried out the Alice Heim 5 task (see part 2).
One week later, the volunteers repeated the procedure
in the other condition (gum or no-gum). Table 2 shows
the testing procedure for a volunteer tested in the order
gum/no-gum.
Gum was the volunteer’s choice of the commer-
cially available product they preferred.
Inclusion/exclusion criteria
Inclusion/exclusion criteria are shown in Table 3.
Tests
1. Mood – This was measured using 18 bipolar visual
analogue scales (e.g. drowsy–alert, tense–calm)
presented on the screen of an IBM-compatible
computer. Mood was rated at the start of each
session and at the end. This provided information
about initial and longer term effects of the
manipulations. Three scores were derived from the
mood scales: alertness, hedonic tone and anxiety.
2. Memory for information in a story – The stories
selected were short stories by Somerset Maugham
(Mr Knowall and A string of beads). These were
not familiar to current students and it was easy to
select questions about important and trivial details
of the story. Recall was tested by open-ended
questions (available from the author).
Interpolated memory tasks
I Immediate free recall task – A list of 20 words was
presented on the PC screen at a rate of one every
2 s. At the end of the list, the volunteer had 2 min
to write down (in any order) as many of the words
as possible.
2. Logical reasoning task (a measure of working
memory) – In this task, the volunteers were shown
statements about the order of the letters A and B
followed by the letters AB or BA (e.g. A follows B:
BA). The volunteers had to read the statement and
decide whether the sentence was a true description
of the order of the letters. If it was, the volunteer
Nutritional Neuroscience 2009 Vol 12 No 2 85
Smith Chewing gum and intelligence test
Table 2 Schedule of testing for participant 1 (gum at both
learning and recall)
Test session Tests Gum during
carried out session (Y/N)
Familiarisation All tests N
Test 1 Y
Mood
Story
Free recall
Logical reasoning
Semantic processing
Delayed recall
Recognition memory
Recall of story
Mood
2 days later Y
Mood
Recall of story
Alice Heim task
Mood
One week after test 1 N
Mood
Story
Free recall
Logical reasoning
Semantic processing
Delayed recall
Recognition memory
Recall of story
Mood
2 days later N
Mood
Recall of story
Alice Heim task
Mood
Table 3 Inclusion/exclusion criteria
Is the participant able to chew gum for a period of approximately 45 min? Yes NNoo
Is the participant aged between 18 and 40 years? Yes NNoo
Does the participant consume more than 40 units of alcohol per week? YYeessNo
Does the participant smoke more than 10 cigarettes in the daytime and evening? YYeessNo
Is the participant currently taking any medication? YYeessNo
Is the participant currently experiencing any medical problems (including dental problems)
or have any serious medical conditions (including phenylketonuria (inability to tolerate
phenylanaline i.e. additives in foods), diabetes, heart or kidney disease)? YYeessNo
Does the participant suffer from any allergic reactions to mint or fruit flavours? YYeessNo
Any response to the ‘bold’ categories excluded the participant from the study.
pressed the T key on the keyboard; if it was not,
they pressed the F key. The sentences ranged in
syntactic complexity from simple active to passive
negative (e.g. A is not followed by B). Volunteers
carried out the task for 3 min.
3. Semantic processing task – This test measured
speed of retrieval of information from general
knowledge. Volunteers were shown a sentence and
had to decide whether it was true (e.g. canaries
have wings) or false (e.g. dogs have wings). The
number completed in 3 min was recorded, as was
the accuracy of responding.
4. Delayed free recall task – After the other tasks, the
volunteer had 2 min to write down (in any order)
as many of the words as possible from the list
shown at the start of these tasks.
5. Delayed recognition memory task – At the end of the
test session, volunteers were shown a list of 40 words,
which consisted of the 20 words shown at the start of
the session plus 20 distracters. The volunteers had to
decide as quickly as possible whether each word was
shown in the original list or not.
PART 2
Unpublished research at New York University has
shown that chewing gum may improve the written
examination performance of dental students. This was
tested here using a test of different types of
intellectual functioning (verbal and numerical skills
and non-verbal intelligence) that is suitable for
university students from a range of disciplines (the
Alice Heim 5 test [AH5]24). Each test session lasted for
20 min and the tests were completed after the delayed
recall tests in part 1. In other respects (design, sample
size, etc.), the study was identical to part 1. Again, a
cross-over design with n= 120 provides greater power
than the original study of gum and test performance
in dental students.
Analyses of variance were carried out with the
within-subject factor of gum/no-gum and the between
subject factor of order of gum conditions.
How do the tests relate to the aims of the study?
1. The story task evaluated whether chewing gum
improves learning and memory of text.
2. The mood rating provided an indicator of whether
chewing gum increases alertness.
3. The short memory tasks allowed evaluation of
whether chewing gum improves episodic memory
(immediate and delayed), retrieval of information
from general knowledge (semantic memory) and
working memory (logical reasoning).
4. The Alice Heim test measures verbal and non-
verbal intelligence and allowed one to determine
whether chewing gum improves these skills in a test
situation.
Statistical analysis
This involved analyses of variance with the within
subject factor of gum versus no-gum and the between-
subject factors of ‘order of gum conditions’ and ‘when
gum chewed’ (both learning and test; learning only;
test only). Other task-specific factors were included
for the different tasks (e.g. story recall: immediate
versus delayed recall; important versus unimportant
information).
Results
The results from the first part of the study are shown
in Table 4. The only significant effects of gum were the
increased alertness and hedonic tone at the end of the
test session.
Table 5 shows the results from the second part of
the study. Again, chewing gum was associated with
increased alertness at the end of the session and
improved performance on the Alice Heim test
(significant at the one-tail level).
Discussion
The present study examined four main issues. The first
was to examine whether chewing gum improved
learning and memory of information in a story. The
second aim was to determine whether chewing gum
improved test performance on a validated intellectual
task (the Alice Heim task). A third aim was to
determine whether chewing gum improved
performance on short memory tasks (immediate and
delayed recall of a list of words, delayed recognition
memory, retrieval from semantic memory, and a
working memory task). The final aim was to
determine whether chewing gum improved mood
(alertness, calm and hedonic tone). The results
confirmed that chewing gum increased alertness and
improved intellectual task performance. This is
consistent with the physiological effects of chewing
86 Nutritional Neuroscience 2009 Vol 12 No 2
Smith Chewing gum and intelligence test
gum, which suggest that it increases arousal. Increased
arousal benefits intellectual performance and tasks
involving selective and sustained attention. Smith9has
shown that chewing gum increases the speed of
encoding of new information and he has suggested
that this may reflect changes in cholinergic function.
Episodic memory may be impaired by high arousal
and it is possible that the absence of memory effects in
the present study reflect opposing effects of chewing
on different stages of information processing. This
could plausibly account for the variability in results
from studies of chewing gum and recall of lists of
words.
In contrast to effects of chewing gum on memory,
the alerting effects of chewing appear to be extremely
robust. Indeed, subjective alertness can now be used as
a positive control to determine the sensitivity of
studies examining other functions. Further research is
now required to determine the practical implications
of the alerting effect of chewing gum and to
understand the brain mechanisms that underlie such
changes. However, the alerting effects of chewing gum
are consistent with results from EEG studies13,14 and it
has been suggested that chewing gum activates at least
two types of mechanism, one related to the chewing
and the other to the flavour of the gum.14,15,25 Studies
measuring EMG confirm that EMG activity in
particular facial muscles is related to the mobilization
of energetic resources.16 Mastication also has effects
on both sympathetic and parasympathetic activity.17
Nutritional Neuroscience 2009 Vol 12 No 2 87
Smith Chewing gum and intelligence test
Table 4 Tests carried out in first week
No-gum Gum
Mean SE Mean SE P-value
Alertness before tests 242.98 5.06 241.20 5.21 0.76
Hedonic tone before tests 197.98 3.37 195.20 3.43 0.46
Calm before tests 87.30 1.98 90.00 1.82 0.16
Free recall (number correct) 8.32 0.29 8.45 0.27 0.61
Logical reasoning (number done) 42.36 1.49 40.46 1.18 0.07
Logical reasoning (% correct) 85.21 1.37 85.43 1.43 0.87
Semantic memory (number done) 57.15 1.35 56.08 1.38 0.14
Semantic memory (number correct) 53.74 1.48 52.74 1.49 0.21
Delayed recall (number correct) 6.38 0.28 6.10 0.312 0.28
Recognition memory (hits) 15.46 0.26 14.93 0.28 0.09
Recognition memory (hit RT)* 1102.2 39.57 1102.3 45.13 0.94
Recognition memory (false alarms) 4.36 0.29 4.41 0.29 0.84
Recognition memory (false alarms RT)* 1458.5 73.47 1413.6 61.82 0.72
Story – immediate recall (total) 6.14 0.18 6.28 0.18 0.44
Story – immediate recall (unimportant) 2.33 0.09 2.36 0.09 0.88
Story – immediate recall (medium) 1.30 0.07 1.35 0.06 0.22
Story – immediate recall (important) 2.52 0.09 2.56 0.10 0.70
AAlleerrttnneessss aafftteerr tteessttss222277..557755..2233224455..555544..666600..000022
HHeeddoonniicc ttoonnee aafftteerr tteessttss118866..229933..3333119933..662233..226600..0022
Calm after tests 85.36 1.80 87.32 1.78 0.27
Story – delayed recall (total) 4.41 0.18 4.36 0.17 0.72
Story – delayed recall (unimportant) 0.90 0.08 0.84 0.09 0.73
Story – delayed recall (medium) 0.91 0.07 0.81 0.06 0.17
Story – delayed recall (important) 2.61 0.10 2.71 0.09 0.54
High scores indicate good performance/mood unless marked with an asterisk.
Table 5 Tests carried out in second week
No-gum Gum
Mean SE Mean SE P-value
Alertness before testing 236.27 5.12 229.88 5.02 0.27
Hedonic tone before testing 191.60 3.25 192.49 4.31 0.80
Calm before testing 86.76 1.74 86.44 1.93 0.90
AAlliiccee HHeeiimm ––nnuummbbeerr ccoorrrreecctt1133..339900..44881133..992200..555500..004455 ((11--ttaaiill))
Alice Heim – speed 19.22 0.14 19.27 0.16 0.73
AAlleerrttnneessss aafftteerr tteessttiinngg222222..994455..5599223366..226655..332200..0011
Hedonic tone after testing 182.11 3.67 186.81 3.27 0.16
Calm after testing 81.16 1.81 81.18 2.01 0.77
Studies of brain imaging also demonstrate that chewing
activates wide-spread regions of the brain.18–21 Other
research has demonstrated that chewing gum influences
neurotransmitter function, specifically the 5-HT
descending inhibitory pathway.22
Acknowledgement
The research described in this paper was supported by
a grant from the Wrigley Science Institute.
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