Physiological, motivational, and cognitive effects of aircraft noise on children: moving from the laboratory to the field.

A combination of laboratory and field methodologies is suggested as a strategy to increase the influence of psychological research in the formation of public policy, A naturalistic study of the effects of aircraft noise on elementary school children is presented as evidence for the effects of community noise on behavior and as an example of a study that examines the generality of laboratory effects in a naturalistic setting. The study is concerned with the impact of noise on attentional strategies, feelings of personal control, and physiological processes related to health. In general, the results are consistent with laboratory •work on physiological response to noise and on uncontrollable noise as a factor in helplessness. Thus children from noisy schools have higher blood pressure than those from matched control (quiet) schools. Noise-school children are also more likely to fail on a cognitive task and are more likely to give tip before the time to complete the task has elapsed. The development of attentional strategies predicted from laboratory and previous field research was, on the whole, not found. The implications of the study both for the understanding of the relationship between noise and behavior and for the influencing of public policy are discussed, Science's contribution to social policy decisions regarding noise pollution has been primarily limited to the documentation of the impact of highintensity sound on hearing. Acceptable noise standards used in both national and local statutes are based on research that assesses magnitude of hearing loss at varying intensities and durations of sound. Yet during the last-ten years it has become clear that noise can alter nonauditory systems as well as auditory ones. Thus laboratory research has established effects of noise on cognitive, motivational, and general physiological proVol. 35, No, 3, 231-243 cesses. For example, noise is associated with alterations in task performance (cf, Broadbent, 1978; Loeb, 1979), decreased sensitivity to others (e.g., S. Cohen & Lezak, 1977; Ma thews & Canon, 1975), and elevation of a number of nonspecific physiological responses (cf. Glass & Singer, 1972; Kryter, 1970). Exposure to noise that is unpredictable and uncontrollable (cannot be escaped or avoided) can also reduce one's perception of control over the environment (e.g., Glass & Singer, 1972; Krantz, Glass, & Snyder, 1974). This loss of control is often accompanied by a depression of mood and a decrease in one's motivation to initiate new responses (Seligman, 1975). One argument against serious consideration of this evidence when making policy decisions is that it is largely derived from laboratory studies. Since laboratory subjects typically experience a single short period of exposure to high-intensity sound and are aware that their exposure is only temporary, the applicability of these findings to experiThe research reported in this article was supported by grants from the National Science Foundation (ENS 7708576 and SOC 75-09224), the National Institute of Environmental Health Sciences (1 R01 ESOI76401 DBR), the Society for the Psychological Study of Social Issues, and the University of Oregon Biomedical Fund. The authors arc indebted to Sheryl Kelly, Laurie Poore, Jerry Lukas, Rich Haller, and Nick Garshnek; to the administrative staffs of the Los Angeles, Lennox, and Inglewood' (California) School Districts; to the staff, teachers, children, and parents of the participating schools; to the California Assessment Program; and to the California Department of Health. We also wish to thank Michael Posner and Myron Rothbart for their comments on an earlier draft . Requests for reprints should be sent to Sheldon Cohen, Department of Psychology, University of O.regon, Eugene, Oregon 97403. AMERICAN PSYCHOLOGIST • MARCH 1980 • 231 Copyright 1980 by the American Psychological Association, Inc. 0003-066X/80/3503-0231500.75 ences of chronic noise exposure is questionable. Because of a lack of well-controlled studies of persons routinely living and working under noise, we are unable to say with any certainty if similar effects occur in individuals exposed to noise for prolonged periods. Our own lack of confidence in the generality of the effects of noise that occurs in laboratory settings translates into a lack of influence in the policymaking process. Legislation restricting noise levels in industrial and community settings usually imposes a heavy economic burden on those responsible for the noise. To convince policymakers that such burdens are justified, there must be substantive evidence that community and/or industrial noise deleteriously affects health and behavior. Naturalistic studies of the effects of noise that occurs in home, school, or office seem like the obvious alternative to investigations carried out in laboratory settings. However, such studies are correlational. Subjects are not randomly assigned to noisy or quiet settings, and the settings often vary on dimensions other than noise exposure, These problems can be substantially reduced by carefully matching the noise and quiet samples on important dimensions and by statistically controlling for other possible confounds. It is always possible, however, that some unknown factor covaries with exposure to the noise setting and actually causes the effects that the investigator associates with noise. Thus, in isolation, naturalistic studies also provide insufficient evidence for a link between community noise and measures of health and behavior. It is clear that neither laboratory nor naturalistic studies can in themselves provide what either scientists or politicians would consider convincing evidence for noise-induced effects. What is necessary is an interplay between laboratory and field methodologies. This interplay can take at least two forms. On the one hand, an effect can first be established as reliable within laboratory settings where causal links can be inferred. Then, the robustness of this relationship can be established in a number of naturalistic settings. On the other hand, by first conducting field research, it is possible to isolate important dimensions of a particular problem. At that point, laboratory studies may be useful to rule out plausible alternate explanations often inherent in naturalistic research. Laboratory and field approaches are often pursued to the exclusion of one another, but only by combining these two strategies can we begin to understand the impact of environmental variables in naturalistic settings. Moreover, only when evidence from the laboratory and field converges can a credible scientific case be presented in order to influence public policy. This emphasis on the interplay between the laboratory and the field is consistent with Campbell and Stanley's (1966) discussion of the inevitable trade-off between well-controlled experimental settings (internal validity) and our ability to generalize across persons and settings (external val id i ty) . The laboratory provides the opportunity for an internally valid investigation, but the generality of laboratory findings is severely restricted. Naturalistic studies provide the opportunity to generalize findings to a greater range of persons and settings but often lack the strict control of the laboratory. The study presented in this article examines the effects of aircraft noise on children. It is particularly concerned with exploring the generality of laboratory work on noise-induced shifts in attentional strategies, feelings of personal control, and nonauditory physiological responses related to health. Our purpose in reporting this study is twofold, First, it is presented as evidence for relationships (or lack of relationships) between aircraft noise exposure and a number of cognitive, motivational, and physiological measures. The article includes short discussions of laboratory and field research in each of the areas of concern. Second, it is presented as an example of an attempt to examine the generality of laboratory effects in a naturalistic setting. In this regard, the study employs an individual testing procedure in a field setting. It uses a matched-group design and attempts to control statistically for a number of possible alternative explanations for correlations between community noise and the various criterion variables. Overview of the Study The subjects were children attending the four noisiest elementary schools in the air corridor of Los Angeles International Airport. Peak sound level readings in these schools are as high as 95 dB (A) , and the schools are located in an air corridor that has over 300 overflights a day—approximately one flight every 2.5 minutes during school hours (Lane & Meecham, 1974). Three control 232 • MARCH 1980 • AMERICAN PSYCHOLOGIST schools (quiet schools) were matched with the experimental schools for grade level, for ethnic and racial distribution of children, for percentage of children whose families were receiving assistance under the Aid to Families with Dependent Children program, and for the occupations and education levels of parents. Thus we were able to compare samples of children attending noise schools and quiet schools who were relatively similar in terms of age, social class, and race. A statistical technique described later allowed additional control over these factors. The study focused on effects occurring outside of noise exposure (i.e., aftereffects). Thus all tasks and questionnaires (except the achievement test records gathered from school files) were administered in a quiet setting—a noise-insulated trailer parked directly outside the school. These data were collected during two 45-minute sessions on consecutive days. Three cognitive tasks were administered during the test periods. One was designed to assess feelings of personal control and the others to determine whether the children employed some common attentional coping strategies. A questionnaire concerned wi