|Home | About | Journals | Submit | Contact Us | Français|
This paper investigates whether mindfulness-based interventions might ameliorate the detrimental health effects of aircraft noise on residential communities.
Numerous empirical studies over the past 50 years have demonstrated the increasing negative impact of aircraft noise on residents worldwide. However, extensive database searches have revealed no published studies on psychological interventions that reduce residents’ reactivity to environmental noise. By contrast, there has been extensive research over several decades confirming the effectiveness of mindfulness-based stress reduction training in lowering people’s stress from work and life. Considering that stress is a major component of aircraft noise reaction, it would seem worth assessing whether mindfulness-based interventions might be effective in reducing the health effects of aircraft noise. It appears that no existing conceptualization of mindfulness specifically accounts for noise as a stressor.
A new conceptual model is presented here which explains how mindfulness can reduce noise reactivity. Two types of mindfulness are distinguished: an active form (meta-mindfulness) and a passive form (supra-mindfulness). It is posited that meta-mindfulness can facilitate “cognitive defusion” which research has confirmed as enabling people to disconnect from their own dysfunctional thoughts. In the case of aircraft noise, negative thinking associated with residents’ reactive experiences can exacerbate the health effects they suffer. The present model further proposes that supra-mindfulness can enable an individual to disengage their own sense of identity from the often overwhelming negative thoughts which can define their existence when they are consumed by extreme noise annoyance.
The mindfulness processes of defusion and disidentification are postulated to be the key efficacy mechanisms potentially responsible for reducing reactivity to aircraft noise. This approach can be evaluated by extending previous research on the health benefits of mindfulness training.
For more than 50 years, aircraft noise has been an ongoing problem in developed countries and an escalating problem in developing countries to the ever increasing health detriment of their residential communities.[1,2] This situation has led to a growing research interest regarding the nature of community reaction to aircraft noise.[3,4] In particular, there has been extensive social survey research aimed at determining the relationship between environmental noise exposure and the subjective reaction of residents.[5,6] For example, Bassarab et al.  published a comprehensive catalogue of no fewer than 628 separate socioacoustic studies of environmental noise reaction that had been reported as of 2008, updating the catalogue of 521 studies published a few years earlier.
From the numerous empirical studies that have been reported in scientific journals over many years, the clear overall finding is that human reaction to aircraft noise is not just a matter of objective noise exposure. Rather, for the typical resident living near any major airport in any country, the average sum of the aircraft noise energy to which they are exposed over the long-term has been found to be the primary determinant of their reaction as distinct from the noisiest overflight, the number of flights above a specified level, or other possible noise indicators.[3,9] However, the same body of research shows that this overall measure explains only a relatively small part (viz., 10–20%) of the dose–response relationship.[5,9,10] The obvious implication is that human reaction to aircraft noise is predominantly influenced by nonacoustic factors which modify the effect of the physical noise. More importantly, it is apparent that complex psychological processes determine how each individual resident will be affected by the noise they experience.[12,13,14]
Such modifying factors include the following: (1) residents’ attitudes toward the noise and those they believe are responsible for it;[10,15,16] (2) residents’ sensitivity to noise;[17,18,19] (3) residents’ ability to tolerate noise; (4) the time of day when the noise is experienced;[21,22] and (5) whether residents have recently experienced a significant change in noise exposure.[23,24] In addition, there are psychological factors such as residents’ expectations about future noise which can alter their current reaction. Further, residents’ aircraft noise reaction has been found to be significantly influenced by both the format and the context of the social survey scales that investigators use to assess their response.[25,26,27]
The physiological effects of environmental noise on humans are well documented.[28,29,30] Babisch has summarized the stress effects of noise as follows: “Noise activates the pituitary-adrenal-cortical axis and the sympathetic-adrenal-medullary axis. Changes in stress hormones including epinephrine, norepinephrine, and cortisol are frequently found in acute and chronic noise experiments. The catecholamines and steroid hormones affect the organism’s metabolism. Cardiovascular disorders are especially in focus for epidemiological studies on adverse noise effects.”
Many researchers have found that residents’ health is negatively impacted by aircraft noise exposure.[32,33] Residents’ self-reported stress levels, for example, have been found to increase with noise exposure whereas their health decreased on a range of measures such as general health, sense of vitality, and mental health. A more recent finding is that the psychological reaction of noise annoyance appears to modify the effect that noise exposure has on cardiovascular health, specifically, hypertension.
A study around Sydney Airport examined the health effects residents experience from high exposure to aircraft noise. The results indicated that residents were more likely to report experiencing stress and hypertension if they had suffered long-term exposure to high levels of aircraft noise as compared with residents not exposed to aircraft noise. This raises the question of whether residents’ negative reaction to aircraft noise can be reduced via direct interventions at the individual level.
Literature searches consistently indicate that there have been no studies that assess procedures which residents might use to reduce their personal stress and other reactions to the aircraft noise they experience in their home. The only relevant paper appears to be an unpublished conference presentation that proposed a possible empirical study to determine whether residents could apply yoga training to reduce the stress they experienced from aircraft noise. The proposal was to teach a form of yoga meditation to a group of people exposed to high levels of aircraft noise in their residences. The proposed form of meditation would have encouraged participants to achieve an ongoing state of “mental silence” or “thoughtless awareness.” However, the projected study did not proceed and no comparable study has been published in the decade since.
Mindfulness is an ancient psychological technique developed over the centuries by Buddhist scholars[38,39] which has over several decades been incorporated globally as part of mainstream professional practice in psychology.[40,41,42,43] Notably, the discipline of psychology has strived in recent years to redefine mindfulness exclusively in scientific and secular terms presumably to disassociate itself from the original spiritual and religious roots of this approach.[44,45]
Undoubtedly, the most widely adopted and successful health application of mindfulness has been in the area of stress reduction. Pioneered by Kabat-Zinn at University of Massachusetts Medical School in 1979,[46,47] mindfulness-based stress reduction (MBSR) has since been implemented in most developed countries.[48,49] The American Mindfulness Research Association monitors the number of academic journal articles on mindfulness published annually since 1980 – their total currently exceeds 4000 including 667 articles from 2016 (https://goamra.org/resources/ Accessed May 8, 2017).
The efficacy of mindfulness has been confirmed in numerous scientific studies but none of them relate to environmental noise.[48,49] For example, Grossman et al.  conducted two meta-analyses of 20 eligible studies covering 1605 patients (out of an initial 64 studies) and found that mindfulness-based programs had statistically significant health effects. This result occurred for both controlled and uncontrolled studies and included stress reduction as well as improvement in various clinical symptoms. Another meta-analysis examined 10 studies selected from 150 published articles on the criteria that they investigated the efficacy of MBSR, measured stress by using validated scales and also reported pre-post quantitative data. These results also indicated that MBSR was effective in reducing stress levels in healthy people. Further, a meta-analysis by Khoury et al.  assessed 29 studies comprising 2668 patients and found that MBSR was effective in reducing stress as well as a number of other ill-health conditions.
A recent study by Gotink et al.  reported a systematic overview and meta-analysis of different systematic reviews of randomized control trials (RCTs) of mindfulness interventions. The interventions investigated were MBSR (see above) and MBCT (mindfulness-based cognitive therapy as pioneered by Teasdale et al. . Out of 187 relevant reviews, 23 met all the inclusion criteria and covered 115 different RCTs and 8683 different individuals suffering from a variety of psychological and physical conditions. When compared with appropriate control groups, the results showed significant improvements in the following conditions: stress, depressive symptoms, anxiety, quality of life, and physical functioning. What is particularly notable about this “meta-meta-analysis” is that it included only studies which used a high degree of methodological rigor, namely, RCTs which employ randomization plus a control group. Despite this increase in rigor, this study confirmed the efficacy of mindfulness interventions across the range of health conditions investigated. No doubt future studies on mindfulness effectiveness will be required to meet the new methodological standards that were applied in this study.
Whereas most studies have used face-to-face training, mindfulness-based interventions are increasingly being delivered via the Internet. A recent article reported a meta-analysis of 15 randomized control studies that tested online mindfulness training for individuals experiencing a range of mental health conditions. The results showed small but significant benefits for depression, anxiety, wellbeing, and mindfulness, with the largest benefit occurring in the case of stress. It is noteworthy that in the hundreds of empirical studies of mindfulness and its efficacy in stress reduction, there have been none which have specifically tested aircraft noise or any other type of noise as a stressor.
There have been a number of attempts to explain the psychological processes that underpin the effectiveness of mindfulness in therapeutic applications.[48,56,57] For example, in an influential paper, Bishop et al. offered an operational definition of mindfulness based on a two-component model: “The first component involves the self-regulation of attention so that it is maintained on immediate experience, thereby allowing for increased recognition of mental events in the present moment. The second component involves adopting a particular orientation toward one’s experience in the present moment, an orientation that is characterized by curiosity, openness, and acceptance.” See also commentaries in response by other theorists.[41,45]
Other conceptual models which explore the mechanisms involved in mindfulness effectiveness include those proposed by Baer et al.  who empirically validated a self-report instrument designed to assess the various facets of mindfulness. Also worthy of note is a comprehensive review by Brown et al.  that compares the various mechanisms employed in ancient and modern approaches to mindfulness. A conceptual model by Teper et al.  proposes that the two essential elements of mindfulness (viz., present-moment awareness and nonjudgmental acceptance of thoughts and emotions) operate iteratively to promote executive control, which then improves the regulation of emotion.
A more recent model of mindfulness emphasizes the role of “positive reappraisal” of a stressor or threat. Unlike defense mechanisms which function by repression or denial, positive reappraisal is an active coping strategy which reevaluates the stressor and alters how it is experienced. According to the researchers, Garland et al., “For one to construe his or her appraisal of a given event as positive, one must disengage and withdraw from the initial appraisal into a momentary state of metacognitive awareness that attenuates semantic evaluations associated with the event.” Thus, the central mechanism in this “mindful coping model” is positive reappraisal which is postulated to occur through the exercise of mindfulness.
In a key review paper, Gu et al.  conducted an analysis of six models of the efficacy mechanisms in mindfulness-based interventions. By using two-stage structural equation modeling of 20 methodologically-sound published articles (out of 169 full text publications) on MBSR and MBCT, the research identified four main mechanisms that proved effective, namely, mindfulness (present moment awareness with nonjudgmental acceptance), repetitive negative thinking (including rumination about the past and worry about the future), self-compassion (including self-acceptance), and cognitive and emotional reactivity (whereby stress triggers negative thinking and emotional behaviors). According to the researchers, “the narrative synthesis described strong and consistent evidence for cognitive and emotional reactivity,” stronger than the other mechanisms identified.
A recent theoretical development in relation to mindfulness is labeled “monitor and acceptance theory” (MAT), which adopts the generally agreed definition of mindfulness (present-moment attention plus nonjudgmental acceptance) as its two central constructs, namely, attention monitoring and acceptance. This theory postulates that the initial efficacy mechanism in mindfulness training is improved capacity for attention monitoring. Such a capacity enables an individual to be more aware of affective information and if operating alone, this skill “heightens affective experience and reactivity, both exacerbating negative symptoms and enhancing positive experiences.” MAT further asserts that acceptance skills in addition to attention monitoring skills are needed to enable an individual to reduce negative reactivity (including stress and anxiety) by disengaging from affective stimuli. It is worth noting that MAT is essentially equivalent to the two-component model of mindfulness efficacy proposed more than a decade ago by Bishop et al. 
Of the various conceptual models of mindfulness reviewed above, the mindful coping model of Garland et al.  would seem to have the greatest relevance to noise reactivity insofar as positive reappraisal can be seen as enabling individuals to reevaluate, and then altering how they experience stressors such as aircraft noise. Little is known about the specific dynamics of residents’ psychological reaction to environmental noise as aircraft noise research to date has almost invariably focused on overall annoyance reaction as measured by a single verbal rating scale. However, the vast literature on mindfulness, although not addressing noise specifically, raises the question of how the psychological dynamics experienced by individuals impacted by environmental noise might compare with those resulting from other severe stressors in life.
A new conceptual model is presented here to explain how mindfulness might prove effective in lowering residents’ reactivity to aircraft noise and other environmental noise impacts. This model is an extension of a previously published model describing the dynamics of mindfulness in stress reduction. The structural foundation of both models is a novel conception of the human psyche, namely, that it comprises three components which are involved in mindfulness-based applications, namely, the sub-selves, the meta-self and the supra-self.
The “sub-selves” (or subpersonalities) are the multiple components of one’s psyche which dominate one’s waking consciousness − indeed, they are the ever-present “voices in one’s head”. According to the model’s proponent, the sub-selves “are not posited as ontologically distinct entities. Rather, they are emergent constructs or experientially-created patterns in our mindchatter, that is, the identifiable ‘voices’ in our mental stream of consciousness.”[64,65] Thus, this approach postulates that when a resident is severely disturbed by aircraft noise, one or more of their sub-selves initially expresses their psychological reaction in terms of reactive thoughts such as: “Why don’t we ever get a break from these endless overflights?” or “When will the Airport stop this incessant noise?” or even “Why are they targeting my house?” For residents who are seriously affected by aircraft noise, such is the extent of their functional self-identity that they may be fully caught up in their immediate reactive thinking without any detachment. Indeed, they may come to identify their very existence with their all-consuming irrational thoughts and concomitant emotional reactions. That is, they effectively become their own cognitive and emotional reactivity (e.g., ranting like an angry person, behaving like a helpless victim, etc.). Note that these are essentially the same psychodynamics as those that occur with rage (e.g., road rage etc.).
The second key component of the human psyche is postulated to be the “meta-self” (meta = among one’s sub-selves) which functions executively as one’s “managing ego.” This component is responsible for ensuring that one can meet the many challenges (large and small) that one has to face each day. In addition, the meta-self “has a monitoring function (via the state of meta-mindfulness) which entails being actively aware of the voices in our mind, that is, the thoughts of our sub-selves as well as the sensations and feelings they experience at every moment we are awake.” Meta-mindfulness can be considered to be equivalent to mindfulness as it is generally applied in contemporary psychology, namely, as an active nonjudgmental process responsible for self-monitoring in the present moment.[41,44,46,48]
The third key component of the human psyche is one’s higher self, here identified as one’s “supra-self” (supra = above one’s mind). Significantly, most people fail to access or even recognize this psychic entity despite the fact that the supra-self is their true self, that is, who they really are. Not surprisingly, this component is almost universally ignored in conceptualizations of mindfulness. The supra-self can be described as one’s “inner-observer” who passively watches one’s own mind here and now, and it is, thus, somewhat similar to the “observing self” in other models of the psyche. “The supra-self operates ‘above mind’ and as subject it is able to observe as objects the activities [and reactivities] of the meta-self and the sub-selves.” Further, the supra-self engages in supra-mindfulness which is a state of completely passive nonjudgmental present-moment inner observation (in contrast with meta-mindfulness above). The passive mental state of supra-mindfulness is a second distinct state of mindfulness, which is different from the active form of mindfulness as it is commonly described in modern psychology.[40,47]
Supra-mindfulness is most readily accessed via “stillness meditation,” which involves totally focusing one’s attention (usually on one’s breath) thereby allowing one’s mind to become empty (typically by repeating a simple phrase which occupies the mind and reduces distraction).[66,67,68] When a person repeatedly engages in supra-mindfulness, they usually come to the fundamental realization that if they can detachedly observe their own mind, then their core being cannot be their mind. They further realize that their own existence must be above their mind and above its reactive contents as triggered, in the present case, by aircraft noise. Eventually, they achieve the life-changing insight that their true existence must be separate from the negative reactivity that their mind experiences when they are overwhelmed by aircraft noise, and thereby their reactivity abates.
Having considered the nature of the three key components of the human psyche, let us now examine the dynamics of their operation in relation to aircraft noise. The model presented in Figure 1 theorizes the dynamics of mindfulness in a training instructional program aimed at reducing an individual’s reactivity to aircraft noise. The model adopts standard conventions, namely, the various geometric shapes identify the main constructs and the arrows indicate the direction of causality of the various effects (with the numbers referring to the explanatory comments in the following text).
[NB. This model is based on that advanced by Hede to explain mindfulness in executive stress reduction. The numbers in the above figure refer to explanatory points listed below.]
Thus, the present model posits that the most effective mechanisms for producing a reduction in aircraft noise reaction are first, defusion of cognitive and emotional reactivity via the process of meta-mindfulness and second, disidentification from reactivity via the process of supra-mindfulness. The model also allows for other possible efficacy mechanisms out of those which have been proposed in existing conceptualizations of mindfulness reviewed above. It will be a matter of systematic empirical investigation to confirm which mechanisms best account for the effects of mindfulness on aircraft noise reaction. Ultimately, future mindfulness training programs can be refined to ensure that residents around airports can acquire those skills, which will be most effective in reducing the negative health effects of aircraft noise.
It is suggested here that residents exposed to aircraft noise should benefit from mindfulness training by using the established principles of the mindfulness-based programs reviewed above. The proposed Aircraft Noise Mindfulness Training program is a course in mindfulness aimed at training residents to reduce their own psychological reaction to aircraft noise by using the same approach as the very successful MBSR programs for stress.[48,49] There are currently hundreds of training courses in MBSR available worldwide, including many affiliated with the original research-based approach developed by Kabat-Zinn et al. at Massachusetts University.[46,47]
An important feature of the Kabat-Zinn method is that it is basically cause-neutral. In other words, MBSR training develops the psychological skills needed for stress reduction without requiring participants to address the specific causes of their stress.[46,47] Essentially, mindfulness training enables people to detach from their stress and from all its possible causes. Similarly, the proposed Aircraft Noise Mindfulness Training program aims to provide residents with the psychological skills they need to reduce their emotional reactivity without having them focus on the specific cause of their reactivity, namely, aircraft noise. In other words, the proposed program should enable participants to observe in the present, the negative thoughts and feelings that are triggered by the aircraft noise they experience. They should be able to detach themselves from such mental contents, thereby reducing the intensity of their reactivity.
As with the widely successful MBSR program,[51,52] the proposed Aircraft Noise Mindfulness Training program comprises training over an extended period (in this case, 8 weeks). Such a time frame is needed not for instruction in content, but rather to allow participants to develop their mindfulness skills through their daily practice over time. Ideally, participants would meet for 2h each week with an instructor who would encourage them to undertake mindfulness exercises for 20min each day (preferably, twice per day). The main mindfulness exercises in the MBSR program are mindfulness meditation and body scanning. In the present model, these exercises involve the active process of meta-mindfulness [Figure 1]. Mindfulness training includes guidance of these two exercises and provides advice regarding which exercise to undertake each day throughout the .
Mindfulness meditation aims to train participants in the active but neutral and nonjudgmental monitoring of the thoughts and feelings that occur in their mind. If reactive thoughts arise in relation to noise, for example, the person is trained to simply observe them with detachment and without any attempt to comment on them, or to change them in any way. In addition to mindfulness meditation, participants learn to practice “cognitive defusion” to reduce the intensity of their reactive thoughts [Figure 1]. Cognitive defusion refers to the process of deliberately disrupting the dysfunctional thought processes associated with a range of psychological states including anxiety, depression, and emotional reactivity. This process is most directly linked to the mindfulness-based intervention developed by Hayes and called “acceptance and commitment therapy” which is now widely practiced in clinical psychology. The other basic mindfulness exercise in MBSR is body scanning which entails the active and systematic focusing of attention on each part of one’s body again without judgment or mental commentary.
As well as these two mindfulness exercises from the standard MBSR program, the proposed Aircraft Noise Mindfulness Training program includes specific training in supra-mindfulness which is proposed as a complement to standard mindfulness in MBSR (the latter being identified as meta-mindfulness in the present model − refer to Figure 1). It is theorized here that competence in supra-mindfulness is most effectively developed from an individual’s experientially based skills in meta-mindfulness acquired via standard MBSR training. Once an individual has learnt to actively observe with detachment and without judgment or commentary, or the reactive thoughts and feelings that often overwhelm their mind, they are then able to learn how to rise above their mind altogether. This enables a resident to not only apply cognitive defusion to the negative thoughts they experience in reaction to aircraft noise, but also to completely disconnect their identity from their reactive mind. They thereby significantly reduce the psychological impact of the noise. In doing so, they encounter their own supra-self which constitutes the above-mind core of their essential being.
The dependent variables for the proposed research on the Aircraft Noise Mindfulness Training program would entail measuring each participant’s initial level of reaction to aircraft noise by using internationally agreed rating scales.[25,62] Also, each participant’s stated home address would be used to locate their residence in relation to the relevant airport and this would enable precise calculation of their objective level of noise exposure by using the accepted international standard for aircraft noise modeling, namely, the Aviation Environmental Design Tool.[72,73] In addition, measures would be taken of each participant’s level of noise sensitivity.[18,19] These and related measures would be repeated at 2-week intervals, thus providing the progressive data needed to evaluate the effectiveness of the mindfulness program as applied to aircraft noise.
The foundation for this research is the question whether mindfulness training might prove effective in reducing the detrimental health effects of aircraft noise on residents considering that over several decades, there has been extensive published evidence that individual stress can be reduced by instruction in mindfulness practice. From the current review of the key findings from 50 years of research on the effects of aircraft noise, the indubitable conclusion is that psychological factors, not objective noise levels, are the primary determinants of individual reactivity and associated health effects. In addition, the extensive findings of mindfulness interventions in reducing stress, specifically the various meta-analytic studies reviewed here, have repeatedly confirmed the existence of an association between mindfulness and a reduction in individual stress levels.
As grounds for proposing that mindfulness-based stress research should be extended into the area of aircraft noise, the present review offers a new conceptual model that illustrates the possible dynamics by which such a beneficial effect might occur. Although there is a number of existing conceptualizations of mindfulness efficacy mechanisms, the proposed model breaks new ground in explaining how two different types of mindfulness could play complementary roles in reducing noise reactivity, namely, defusion and disidentification.
The logical approach in future empirical research on mindfulness and aircraft noise would be to apply the well-established MBSR training in residential areas around several major airports in several countries. Such a mindfulness training program could be readily extended with the two-mindfulness model offered here. If the proposed approach proves effective with aircraft noise, it could be extended to investigating other forms of environmental noise that impact negatively on residential communities. The potential benefits to community health worldwide are considerable.
University of the Sunshine Coast, Australia.
There are no conflicts of interest.