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Appetite

Volume 56, Issue 2, April 2011, Pages 299-301
Appetite

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The role of time on task performance in modifying the effects of gum chewing on attention

https://doi.org/10.1016/j.appet.2010.12.021Get rights and content

Abstract

Recent research examined the effects of chewing gum on attention and reported a significant interaction of gum chewing with time. Using a crossover within-subject design, the present study examined the effect of gum chewing on sustained attention in healthy adults over a period of 30 min. The results revealed a significant main effect of time and a significant interaction between gum chewing and time. The findings suggest that gum chewing differentially affects attention performance. While gum chewing has detrimental effects on sustained attention in earlier stages of the task, beneficial effects on sustained attention were observed at later stages.

Research highlights

► Examination of impact of gum chewing on cognition over a prolonged period of time. ► Significant main effect of time and interaction between gum chewing and time. ► Detrimental effects of gum chewing during earlier stages of task performance. ► Beneficial effects of gum chewing during later stages of task performance.

Introduction

It has been observed that the chewing of a piece of ordinary chewing gum can facilitate cognition (Baker et al., 2004, Houcan and Li, 2007, Johnson and Miles, 2008, Stephens and Tunney, 2004b, Wilkinson et al., 2002). With regard to attentional functioning, beneficial effects of gum chewing have been found on alertness, selective attention, language-based attention and sustained attention (Scholey et al., 2009, Smith, 2009b, Smith, 2010, Stephens and Tunney, 2004b, Tucha et al., 2004b). This facilitation of cognitive functioning by gum chewing has been ascribed to a chewing-related increase of regional cerebral blood flow, in particular in fronto-temporal brain regions, and an enhanced release of insulin. However, several studies failed to replicate these findings or demonstrated that gum chewing may even adversely affect attentional functioning (Kohler et al., 2006, Rost et al., 2010, Smith, 2009a, Tucha et al., 2004b, Wilkinson et al., 2002).

The difficulties in replicating the results of studies have been attributed to methodological differences between studies. Comparisons between studies revealed that studies differed in regard to statistical power, the test procedures applied, the brands of chewing gums used, the participants’ familiarity with chewing gum (because of their different nationalities), the experimental designs (within- versus between-subjects design, lack of baseline assessments), the statistical analyses performed (parametric versus non-parametric analysis) and possible changes in gum consistency and flavor during the course of the examination (Scholey, 2004a, Scholey, 2004b, Stephens and Tunney, 2004a, Tucha et al., 2004a). Although the studies differed in all of these aspects, it appears that no single factor or combination of factors can explain the disagreement of results of available studies.

In a recent study a new idea was put forward that might explain why some studies found beneficial and others detrimental effects of gum chewing on cognition (Tänzer, von Fintel, & Eikermann, 2009). This idea focuses on time as an important factor in the psychodynamics of gum chewing. In their study, Tänzer et al. (2009) examined concentration performance in 8–9 year-old children by using a cancellation task for a period of 16 min. Children who chewed a piece of chewing gum throughout the test session performed more poorly than the children who did not chew gum. However, this difference was only present during the first part of the task. After the twelfth minute, children who chewed a piece of gum outperformed the children of the no-gum-condition. Statistical analysis revealed that the interaction between conditions (gum chewing versus no gum chewing) and test period (earlier parts versus later parts of the task) was significant. In their discussion, Tänzer et al. (2009) mentioned that the poorer concentration performance of children chewing gum might have resulted from a biased selection of children with regard to their concentration performance. However, since no baseline assessment of concentration performance of groups has been performed, this is only one possible speculation. On the basis of the available literature, one could also assume that gum chewing might have detrimental or no effects on performance at earlier stages of tasks and beneficial effects at later stages. This explanation receives some support by a closer inspection of the sequence and timing of tests as applied in available studies. While some studies reporting beneficial effects of gum chewing on cognition observed the effects in tests that were performed during later stages of assessment (e.g. Smith, 2009b, Smith, 2010, Tucha et al., 2004b, Wilkinson et al., 2002), studies that failed to replicate these effects performed similar measures at the beginning of assessment (e.g. Johnson and Miles, 2007, Tucha et al., 2004b). However, the evidence provided by an inspection of the test sequences as used in published studies is not clear-cut because there is a lack of detail in publications concerning the exact timing and duration of tasks. Furthermore, positive effects of gum chewing on cognition were also observed at early stages of assessment (Smith, 2009a, Wilkinson et al., 2002). Therefore, it remains unclear whether time represents a mediating factor in the effects of gum chewing on cognition.

The aim of the present study was to examine the impact of gum chewing on cognitive performance over a prolonged period of time. Using a computerized task that has been shown to be sensitive to the effects of gum chewing (Tucha, Mecklinger, Maier, et al., 2004), attention performance of healthy adults was registered for a period of 30 min.

Section snippets

Methods

Forty-two healthy adults participated in the present study (21 female, 21 male; mean age = 22.2 years, SD = 2.4 years). The study used a crossover design in which participants were assessed both with chewing gum (gum-condition) and without chewing gum (no-gum-condition). In the gum-condition, participants were asked to chew naturally and constantly a piece of spearmint flavored sugar-free chewing gum throughout the whole test session. Half of the participants were tested first with chewing gum and

Results

There was no evidence to reject the assumption of normal distribution of reaction time data. Because of a violation of the sphericity assumption, the Greenhouse–Geisser correction was employed. Multivariate analysis of variance (MANOVA) revealed a significant main effect of time block (F(4.06, 205) = 17.13, p < .001, Greenhouse–Geisser corrected). The effect size for this difference in reaction time was large (η2 = .295). Subsequent post hoc analysis using paired t-tests (Bonferroni adjusted)

Discussion

In the present study, the effect of gum chewing on attentional functioning over a prolonged period of time was examined. Attentional functioning was assessed by performing a computerized sustained attention task. Reaction time was measured for each of six consecutive time blocks of 5 min so that changes in test performance over time could be analyzed. An analysis of the number of omission and commission errors was not included in the present study, because errors in healthy participants have

References (26)

  • L. Tucha et al.

    Detrimental effects of gum chewing on vigilance in children with attention deficit hyperactivity disorder

    Appetite

    (2010)
  • L. Wilkinson et al.

    Chewing gum selectively improves aspects of memory in healthy volunteers

    Appetite

    (2002)
  • J. Brisswalter et al.

    Effects of acute physical exercise characteristics on cognitive performance

    Sports Medicine

    (2002)
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