Causes of 'imbalance approach': aviation noise management

By Pieter Jan Stallen

Airneth Column 
December 2010
By Pieter Jan M. Stallen

Social science, to the extent that it always is the study of human decision making (however little room for free will two decades of neuropsychological boost have left over), could be considerably more difficult than natural science. On the one hand there is the principled reason that ‘environment with knowledge of study results’ cannot be equated any more to ‘environment without’. On the other hand, there is the practical reason that each of us believes that study results, being essentially group averages, will apply to almost everyone… except ourselves. The conviction ‘I am no average person’ stems from differential beliefs about control by Self compared to Other in case of good outcomes, and the opposite -less control- in case of bad. We systematically underestimate uncertainty indeed. We estimate probability by plausibility (remember, it is story telling, in the end, that distinguishes us from the chimp) and we are unaware of the hindsight bias it creates. As a consequence, the idea that choices of Self, much more than those of Other, are not determined by our environment becomes a liked idea. “Do you think that YOU did determine what I do? Come on, I am not that weak!”

Heavens sake, what does it have to do with aviation noise management?

Everything. After some 2 decades of closeness to aviation noise policies, with 10 years at the Leiden University Chair ‘Community Noise Annoyance’, I think that the observations above describe at the deeper level the difficulties of aviation noise policies in becoming somewhat balanced approaches.

When speaking about aircraft, noise is unwanted sound (unfortunately, needed linguistic discussion must await another column). Noise is not solely decibel, Leq, Lmax or whatever other descriptor of physical load but noise is ‘decibel AND unwanted exposure’. Noise is You expose Me. Thus, noise is always both physical AND social environment. Already the first investigations of aircraft noise 
-community responses around US military bases in the 50-ies- revealed the predictive power of psychological factors. The great many studies since have shown univocally that affective responses to aircraft exposure are determined by both acoustic and non-acoustic factors, with each set carrying roughly the same weight. Therefore, todays most interesting findings about how to reduce negative impacts of residential exposure to aircraft sounds are reported by scientists (whether acousticians, epidemiologists or other) studying how both pure physical (decibel) and context factors together affect the psychological and physiological complex. The most common denominator of their stress theories is ‘perceived control’, especially the (unconscious) predictability of loss of benefits and behavioral resources. As such losses by Self are always relative to losses by Other, in fact, noise appears a deeply social affair (e.g., google ‘noise social context’). 

But then, if this is the state of scientific art, the more interesting question arises: why do noise reduction policies still stick to the Dose (decibel)-Response (percentage annoyance) paradigm instead of shifting to more environment or social factor based policies? Policy scientists know that such shifts need the simultaneous presence of several critical push and pull factors. Regarding aviation noise I have observed but absence of this presence. At the push side the critical factors are ‘crisis’ and ‘leadership’. (1) Crises mostly require sudden changes of exposure, as for new flight patterns. Crises usually do not follow from incremental changes or from more of the same, like capacity growth. Crises may flow from sudden detection of significant health impacts but the scientific evidence of a direct link from nightly noise load to such impacts is weak. (2) Leadership is a condition sine qua non. In aviation it requires similar assessments of urgency and direction by airport authority, air traffic control, home carrier. Their often quite opposed interests don’t make leadership easy. Equal difficulties arise at residential sides where often several municipalities fall under the same noise footprint. At the pull side policy changes need general feel, program and window. (3) ‘General feel’ means that, aside from general policy dissatisfaction, within institutions and representatives of the general public alike there must be some shared and deeper feelings of which direction to go into, and where to deploy our resources. Deeper down, general feel is about power. One may not expect the mere discussion of non-acoustic factors to be power-irrelevant. E.g., environmentalists generally do not like non-acoustic factors as it diverts local attention away from their supra-local goal (however valid in itself): reduction of aircraft movement. (4) The necessity of a practically robust proposal for new yet theoretically sound and coherent measures will speak for itself. Establishing varied conditions for long-winded commitment and mutual accountability (cf. Vienna Austria; Chicago Ill.) is ‘program’. Only on-line flight track information, however advanced, is not. (5) Finally, if a window is closed, you can’t get through. Any proposal must be elaborated in the proper legal context, be set on the proper political agenda, and at the proper point in time. If not, years of delay are guaranteed. 

Whereas ‘crisis’, ‘leadership’ and ‘window’ are beyond most readers control, improving ‘general feel’ and ‘proposal’ are not. By this column I might have raised reader interest in the latter two subjects. If so, then she/he might like to meet ANNA (for contact, see

Category: Pieter Jan Stallen, news & columns, columns