Tài liệu tâm lý học sức khỏe: Stress và môi trường

Several studies of residential crowding find little or no correlates with disease Brett & Benjamin, 1957; Collette & Webb, 1974; Mackintosh, 1934; McKinlay & Truelove, 1947; Quinn, Lowry

20

Environmental Stress and Health

Gary W Evans Cmtell University

Although environmental conditions play a prominent role in health and psychological processes, antecedent factors in these processes have largely been neglected within health psychology Instead, the focus has been on various markers of health, with considerable attention to stress-related mechanisms, interceding between the environment and health Another focus within health psychology that has directed attention away from environmental factors has been coping resources, with the examination of either social support, personality, or coping strategies that potentially alter the impact of environmental demands on health But what characteristics of the environment itself are likely to impinge on health and psychological processes? When this question has been addressed within health

psychology, environment has been operationalized primarily in social terms Family and work social climates, as well as sociocultural and economic conditions, predominate in the few environmental studies in health

psychology This chapter intends to draw greater attention to the potential role of the physical environment in health and psychological processes

Why might the physical environment be important to health psychology? Forone reason, the physical environment clearly impacts health Adverse physical conditions can cause toxicological reactions, challenge homeostatic balance, produce physical trauma, or function as vectors bearing pathogens.Physical factors can also be a source of environmental demands that

pressure coping resources

A second reason the physical environment is worthy of scrutiny within healthpsychology is because the environment can be modified and thus becomes apotential intervention target to improve health and well-being Third,

environmental conditions are objective and thus can be measured more readily in reliable and valid ways For example, researchers can system- atically monitor density or noise levels in precise, accurate ways that can then be examined as possible causal factors in health Fourth, physical environmental conditions tend to be stable Increasingly, research suggests that chronic environmental demands are most likely to have negative impacts on health (Lepore, 1995) Finally, the concept of psychological stressthat is central to several formulations of health, behavior, and disease (see chap 17, this volume) has been utilized to broaden understanding of how physical features of the environment can influence human health and well-being

There are at least three major ways in which the physical environment mightoperate as a psychological stressor, straining human adaptive capacities First, this can occur when a stressor directly loads, or pressures, the system Both crowding and noise, for example, create a surfeit of stimulation that can directly overload the system, causing discomfort, negative affect, and under some circumstances, the marshaling of adaptive resources Both negative affect and adaptive responses to challenge or threat in turn directlyaffect neuroendocrine and cardiovascular functioning Physical stressors can also interact with psychosocial conditions to exacerbate negative affect and/or psychophysiologic mobilization For example, noise plus high

workload demands leads to more serious health outcomes than workload levels alone Noise and crowding frequently covary with other psychosocial

risk factors (e.g., poverty, inadequate working conditions), and thus have the potential to contribute to multiple risk situations

A second manner in which the physical environment can contribute to stress

is by damaging or ameliorating coping resources themselves People rarely respond to suboptimal physical or psychosocial conditions passively;

instead, they

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invoke various coping strategies to reestablish some modicum of balance between environmental demands and personal resources Evidence is presented herein, for example, that crowding interferes with the

development and maintenance of socially supportive relationships in the residential environment Both chronic noise and chronic crowding appear to contribute to learned helplessness, adversely affecting self-efficacy and related motivational processes

The third way in which physical conditions can operate as stressors is to elicit coping strategies that in turn lead to poor health Studies of noise, for example, reveal that increases in substance abuse occur under noisy working conditions

Another aspect of research on psychological stress and health relevant to this chapter on environmental stressors are the concepts of vulnerability andresilience (Cohen, Kessler, & Gordon, 1995; Rutter, 1983) Just as certain personal or situational characteristics can render individuals more or less vulnerable to social stressors, there is evidence of vulnerable subgroups among the population who appear more adversely affected by noise and by crowding, respectively Thus throughout both direct, man effects and

associations between environmental stressors and health, as well as

occasions with vulnerable subgroups, are noted

The field of environmental stress (Cohen, Evans, Stokols, & Krantz, 1986; Evans, 1982; Evans & Cohen, 1987) is sufficiently developed such that exhaustive coverage is impossible A small amount of environmental stress research has examined climatic conditions as potential psychological

stressors influencing human stress responses (Bell & Greene, 1982; Evans, 1994) Research on housing conditions as a possible stressor have also beenundertaken (Framan, 1984) The focus of this chapter is on the two most studied environmental stressors, crowding and noise Health outcomes include physical health and psychological health Moreover, the chapter examines underlying psychosocial psychophysiological processes that may help explain the linkages between noise and crowding and major physical and psychological health outcomes Psychophysiological mechanisms, immune function, social resources, coping strategies, and motivational processes are examined

CROWDING

The element of crowding that relates most strongly to physical and

psychological health is people per room Traffic congestion may also prove to

be a potent stressor Area measures of crowding, such as people per acre, generally have little or no relation to health Although some studies of crowding separate group size effects from density effects, the vast majority

of studies have confounded these two factors, manipulating or measuring

density as it covaries with group size Therefore, some of the effects

attributed to crowding may be clue to group size rather than the amount of space per person At the same time, when attempts have been made to distinguish between these related concepts, density and group size, the impacts of density typically persist

Physical Health

Early interest in crowding in the public health field emanated from concerns about the spread of disease among crowded populations (Cox, Paulus, McCain, & Karlovac, 1982) There is a large literature on this topic Physical health has been operationalized in this literature as rates of illness based on archival data, visits to infirmary, physical development among children, and self-reports of somatic symptoms Archival evidence for positive associationsbetween crowding and ill health come from studies in prisons (McCain, Cox,

& Paulus, 1976; Paulus, 1988), refugee camps (Amow, Hierholzer, Higbee, & Harris, 1977), and schools (Essen, Fogelman, & Head, 1978; Koopman, 1978) The Arnow et al (1977) study is noteworthy because they

demonstrated over time between Vietnamese refugee camp population fluctuations with changes in a highly contagious disease (acute

conjunctivitis) There is also evidence that crowded residential conditions arelinked to disease both among children (Booth & Johnson, 1975; Jacobson, Chester, & Fraser, 1977) and among adults (Levy & Herzog, 1978;

McGlashen, 1977; Menton & Meyers, 1977; Sims, Downham, McQuillin, & Gardner, 1976; Wyndham, Gonin, & Reid, 1978; Yarnell, 1979) Yodfat, Fidel, Cohen, and Eliakim (1979) found that linkages among residential crowding and asthma were due to number of children rather than density per se Booth (1976) found that male adults, but not women, had greater levels of disease in crowded homes Traffic congestion levels among commuters is also associated with illness-related absenteeism from work (Novaco, Stokols,

& Milanesi, 1990)

Several studies of residential crowding find little or no correlates with disease (Brett & Benjamin, 1957; Collette & Webb, 1974; Mackintosh, 1934; McKinlay & Truelove, 1947; Quinn, Lowry, & Zwaag, 1978), and Winsborough(1965) uncovered an inverse relation between area density and tuberculosis.Schmitt and colleagues also found no relation between residential density and disease rates, but found small, positive correlations with area density (people per acre) measures (SGhrnitt, 1966; Schmic, Zane, & Nishi, 1978) Similar trends have been uncovered by Levy and Herzog (1974) Kellett (1984) made the important point that certain diseases should be expected a priori to correlate with crowding more so than others Kellett examined morality patters for specific diseases in London for a S-year period As in prior work, persons per room rather than people per acre appeared more useful in predicting mortality Second, diseases wherein a major stress component is believed to be operative (e.g., hypertension, myogardial infarction, vascular disorders, asthma) were related to household crowding whereas many other diseases (e.g., various forms of cancer) were not Fradman and colleagues challenged many of these studies of crowding and disease, noting that poor or nonexisting controls for other variables such as socioeconomic status are common in the crowding and epidemiological literature They found in a well-controlled residential crowding was not a significant predictor of distiase (Freedman, Heshka, & Levy, 1975) However,the prison

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studies and a few of the residential studies (e.g., Menton & Meyers, 1977) dohave good controls for SES Furthermore, there are trends in the data indicating that when individual levels of exposure to density and individual indices of health are compared rather than aggregated population statistics, such as used by Freedman and colleagues, stronger results occur

Nonetheless, Freedman and colleagues' cautious perspective on crowding and disease is well taken Overall findings are suggestive but not rigorously

or consistently supportive of a crowding-disease link It would be useful to include, in the same individual-based study, disease rates for disorders that ought to vary with stress exposure plus inclusion of immunological

measures

A handful of studies in institutional contexts have examined crowding and infirmary visits These studies converge on positive associations between levels of crowding and infirmary visits among shipboard military personnel (Dean, Pugh, & Gunderson, 1975, 1978), college campus residents (Baron, Mandel, Adams, & Griffen, 1976; Stokols, Ohlig, & Resnik, 1978), and

prisoners (Paulus, 1988) The prison effects were most noticeable among inmates forced to live under dormitory- like conditions rather than in single cells Trends also indicated that the associations in prisons were somewhat stronger for men than women and for African American in comparison to Anglo prisoners (Paulus, 1988) Wener and Keys (1988) found that increases

in density (doubling up cell mates) markedly elevated (nearly 50%) sick call rates among prison inmates

A few studies have examined physical development among crowded

children, uncovering evidence of negative associations between household density and physical stature (Booth, 1976; Essen et al., 1978; Goduka, Poole,

& Aotaki- Phenice, 1992) Crowded children, particularly boys, are shorter Shapiro (1974) also found that boys, but not girls, motoric development appeared to be inhibited in crowded homes Moreover, this effect was amplified among children of less educated mothers More recently,

Widmayer and colleagues (1990) found delayed psychomotor development among infants as a function of household density, controlling for

socioeconomic status (SES)

Self-reported levels of physical illness are positively associated with

crowding in prisons (Cox, Paulus, & McCain, 1984; McCain et al., 1976), among college dormitory women but not men (Karlin, Epstein, & Aiello, 1978), and among crowded home settings (Gove & Hughes, 1983)-although Booth (1976) found this association among men, but not women, in crowdedhomes Giel and Ormel (1977) and Baldassare (1979) failed to replicate the association between home crowding levels and self-reported illness The validity of all the self-report data on illness and crowding is suspect given retrospective self-report indices On the other hand, Cox et al (1984) found

a dose-response function between number of inmates per cell and reported illness levels among male prisoners Of additional interest, Gove and Hughes (1983) provided some evidence that heightened illness levels associated with crowded residences are related to lack of sleep and lower resistance when exposed to other sick family members (all self-reported)

self-There is evidence that some of the association between crowded living conditions and self-reported health symptoms is mediated by loss of

perceived control over the living environment Ruback and associates found that both female and male prisoners' reports of ill health in association with crowding were also negatively related to perceived control (Ruback & Carr, 1984; Ruback, Carr, & Hopper, 1986) Another way in which environmental stressors like crowding can impinge on health is through injuries Rhesus monkeys when crowded, for example, show a 5-fold increase in incidents of

injuries (Boyce, O'Neill-Wagner, Price, Haines, & Suomi, 1998)

Psychophpysiologieal

Several studies have examined the relation between crowding and blood pressure in people Laboratory studies with random assignment to density levels have found small but significant elevations among crowded versus uncrowded participants (Epstein, Lehrer, Csz Woolfolk, 1978; Evans, 1979) Field studies of prisoners (D'Atri, 1975; Paulus, McCain, & Cox, 1978) and automobile commuters (Novaco, D Stokols, Campbell, & J Stokols, 1979; Schaeffer, Street, Singer, & Baum, 1988; Stokols et al., 1978) have also revealed correlational evidence for elevated blood pressure under more crowded or congested living or commuting conditions The commuting studies have found that the effects are stronger for car poolers rather than solo drivers, for Type B rather than Type A drivers, among external versus internal locus of control drivers, and among drivers with less residential choice One field study found no relations between chronic residential crowding and blood pressure or neuroendocrine indices among adults (Booth, 1976), although small, statistically significant elevations in serum cholesterol were noted among crowded men No such correlation was noted among women Booth's sample did not vary much in density, which may have weakened his findings Evans, Lepore, Shej wal, and Palsane (1998) found elevated blood pressure among crowded boys, but not girls, among working- class families in India

Another cardiovascular function, blood pressure reactivity, has been related

to chronic crowding in adults Residents of more crowded neighborhoods hadhigher reactivity (increase from baseline in blood pressure levels) and took longer to return to resting baseline levels (Fleming, Baum, Davidson,

Rectanus, & McArdle, 1987) Both heightened reactivity and protracted recovery to baseline are potentially important precursors to the

development of coronary heart disease

Neuroendocrine markers of stress, typically urinary catecholamines and cortisol, have been noted in several studies of crowded commuters

(Lundberg, 1976; Singer, Lundberg & Frankenhaeuser, 1978) and among busdrivers operating under more congested driving conditions (Evans & Carrere,1991)

Pedestrian exposure to more crowded urban areas elevates neuroendocrine activity, at least for males (Heshka & Pylypuk, 1975), and residence in neighborhoods perceived as more crowded because of commercial

establishments and more people on the street is associated with increased urinary catecholamine levels (Fleming, Baum, & Weiss, 1987) Dormitory

-367-crowding, however, had no apparent effects on neuroendocrine activity among college students (Karlin et al., 1978) A small sample size may have rendered low power These authors did find, however, that uncrowded residents' neuroendocrine indices dropped over the course of the semester, whereas crowded residents' neuroendocrine levels increased over the same time period Schaeffer, Baum, Paulus, and Gaes (1988) found that prisoners housed in more open, unpartitioned dormitories felt more crowded and experienced elevated chronic catecholamine levels in comparison to

prisoners living in smaller groups

The critical role of control has been implicated in some of these

psychophysiological crowding studies Lundberg (1976) and his colleagues found that passengers with greater choice over seating were less negatively impacted by congested commuting Evans and Carrere (1991) found that theneuroendocrine effects of traffic congestion on bus drivers were largely mediated by perceived control on the job On the other hand, perceived control did not mediate the positive relation between prison crowding and neuroendocrine elevations (Schaeffer, Baum, Paulus,

A few laboratory studies have also utilized skin conductance as an index of psychophysiologic stress, generally finding elevations among more crowded participants (Aiello, Epstein, & Kalin, 1975; Aiello, Nicosia, & Thompson, 1979; Bergman, 1971; Nicosia, Hyman, Karlin, Epstein, & Aiello, 1979) Studies of crowding and skin conductance are evenly split on gender

differences, with some studies finding more pronounced effects among males than females and other studies finding no sex differences There is also evidence that skin conductance may be more strongly affected by crowding when physical touching occurs McCallum, Walden, and Schopler (1979) found that acute crowding elevated palmar sweat but only when experimental subjects were motivated to maintain high levels of group performance When performance was permitted to deteriorate under

crowding, no physiological elevations were noted Finally, in a field study, Cox, Paulus, McCain, and Schkade (1979) found a significant positive

correlation between the palmar sweat index and crowding among prison inmates

Although indirect, some findings by Hutt and Vaizey (1966) may shed some light on psychophysiological mechanisms associated with crowding and psychophysiologic responses Chronically overaroused children responded tohigh density laboratory conditions by extreme social and physical

withdrawal; whereas chronically underaroused children and children without arousal disturbance reacted in the opposite direction, becoming more engaged and aggressive with other children

Many animal studies have examined endocrine activity among crowded species both under laboratory and field conditions (see Evans, 1978, for a review) Generally, this research indicates support for a population

regulation feedback mechanism whereby crowded animals' fertility declines.This occurs more markedly among subordinate rather than dominant

animals and appears to be mediated by adrenal cortical activity Attempts tolink crowding with population regulation among human beings have proven futile

Immune Function

Animal but not human work has examined immunological processes as a function of crowding, generally finding evidence of compromised immune functioning among more crowded animals (Christian, 1963; E A Edwards & Dean, 1977; Thiessen & Rodgers, 1961) These effects appear to be strongeramong subordinate rather than dominant animals and among animals without a history of crowded living conditions (Cassel, 1971) Cassel(1974) pointed out, however, that compromised immune function alone cannot account for changes in morbidity among crowded animals because both infectious and noninfectious diseases are elevated among crowded animals

Psychological Health

Ever since 1962 when Calhoun published his famous Scientific American study of pathology among overpopulated rats, researchers and policymakersalike have wondered about the potential role of crowded living conditions on mental health The chapter first reviews research on linkages between density and psychological distress and then turns its attention to recent work examining possible underlying mechanisms for this linkage

Many studies have uncovered positive relations between residential density and self-reported psychological distress (Edwards, Fuller, Sermsri, &

Vorakitphokatorn, 1990; Evans, Palsane, Lepore, & Martin, 1989; Gabe & Williams, 1987; Gove & Hughes, 1983; Hassen, 1977; Jain, 1987; Lakey, 1989; Marsella, Escudero, & Gordon, 1970) Mitchell (1971) found greater worrying among crowded families but only if they were also poor Crowding

in Mitchell's study was unrelated, however, to more serious indices of psychiatric illness Lepore, Evans, and Schneider (1991) found evidence thatresidential crowding causes psychological distress in a prospective,

longitudinal study of crowding and mental health Controlling for educationallevels and income, they found that crowded residents did not differ from uncrowded residents in psychological distress symptoms during initial occupancy (I- = 12), but after 2 months and 8 months the associations became significant (r = 21; r = 27) This is the only prospective study of crowding and health Webb and Collette (1975) found an association

between residential density and use of prescription hypnotics

Booth (1976), Baldassare (1979), and Giel and Ormel (1977) failed to find a positive association between residential crowding and psychological distress.These studies had little variance in density Moreover, Baldassare relied on mental health indices of questionable sensitivity (one dichotomous item in one case, and three dichotomous items in a second case) Two studies of neighborhood crowding levels have also found linkages to psychological distress (Collette & Webb, 1974; Fleming, Baum, $I Weiss, 1987)

Studies utilizing archival indices such as psychiatric admissions or suicide rates generally find very weak or insignificant associations between

crowding and pathology when measured in the aggregate (Freedman et al., 1975; Gove &

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Hughes, 1980; Schmitt, 1966; Schmitt et al., 1978) In some studies

negative associations between density and psychiatric admissions have been uncovered, probably created by the association of living alone and mental disorder (Galle, Gove, & McPherson, 1972; Levy & Herzog,

1974/1978) One exception to these generally negative trends in archival indices of mental health and crowding is notable Several prison studies have found clear, strong associations between the total population size of prison populations and indices of psychiatric illness (Paulus, 1988)

Quite a number of studies have examined psychological symptoms among children living in crowded homes Plant (1937) described several case studies noting a pattern of low self-sufficiency and little idealism among children from crowded homes He attributed these patterns to mental strain associated from always having to get along with others and to exposure to adults under close quarters that made it difficult to look up to or idealize grownups Crowded children have increased levels of various symptoms of psychological distress (Booth, 1976; Gasparini, 1973; Murray, 1974; Saegert,1982; Wachs, 1987) Parents in more crowded homes report relief when theirchildren are outside (Gove & Hughes, 1983), have more difficulty supervising

their children (Mitchell, 197 l), and are generally less responsive and

involved with their children (Bradley & Caldwell, 1984; Evans, Maxwell, & Hart, 1999; Wachs & Camli, 1991) in comparison to uncrowded parents of comparable social class These trends appear to be exacerbated in the presence of other risk factors, particularly poverty (Baldassare, 1981; Bradley et al., 1994)

Psychosocial Resources

Some of the relation between high residential density and psychological distress in children may be linked to family interactions, which have been found to be more contentious under crowded living conditions (Booth, 1976; Gasparini, 1973; Saegert, 1982) There may also be greater incidence of physical punishment and open expression of anger between parents and children in crowded homes (Booth & Edwards, 1976; Light, 1973), although Gove and Hughes' (1983) study did not support this finding

Another factor that may help explain the link between high residential crowding and symptoms of psychological distress in children is withdrawal Aiello, Thompson, and Baum (1985) reviewed several field and laboratory studies documenting increased social withdrawal under crowded conditions among young children Similar trends exist in the adult literature, indicating that crowded adults interact with housemates less (Baum & Valins, 1977, 1979; Proshansky, Ittelson, & Rivlin, 1970); are less friendly with their neighbors (McCarthy & Saegert, 1978), and have impaired social support with those they live with (Evans et al., 1989; Lakey, 1989; Lepore et al., 1991) Baldassare (1979) did not replicate linkages between residential crowding and neighboring People under crowded conditions also tend to be less affiliative in their behaviors toward others (R L Munroe & R H Munroe, 1972) and view others in more negative or suspicious terms (Bickman et al., 1973; Griffit & Veitch, 1971; McCarthy & Saegert, 1978) There is also evidence that crowded working conditions lead to greater social withdrawal from coworkers (Oldham & Fried, 1987) Finally, as already noted, parents in crowded homes are less responsive to their children (Bradley & Caldwell, 1984; Wachs Bt Camli, 1991) Furthermore, this relative unresponsiveness partially accounts for less complex parent to child verbalizations to infants and toddlers (Evans, et al., 1999)

Evidence that social withdrawal and impaired social relationships are a primary mechanism accounting for the relation between crowding and psychological distress has been documented in some detail by two research programs Baum and colleagues found that more crowded dorm residents report more unwanted social interaction in their dorms These same crowdedresidents also evidence greater behavioral indices of withdrawal outside of the dorm They sit farther away from other research participants and

withdraw more in group interaction games (Baum & Valins, 1977, 1979) Residential exposure to high levels of street traffic is also associated with less neighboring (Appleyard & Lintell, 1972; Halpern, 1995) Evans and Lepore showed direct evidence for a similar pattern They found both cross-sectionally (Evans et al., 1989) and in a prospective, longitudinal design (Lepore et al., 1991) that the negative effects of residential crowding on psychological distress (with controls for social class) are mediated by social support Similar patterns also appear to occur among children in crowded residences (Evans, et al., 1998)

Evans and Lepore (1993a) also found that crowded relative to uncrowded residents were less likely to offer support to a confederate under stress in an

uncrowded laboratory setting Of additional interest, crowded residents in comparison to uncrowded residents were also less responsive to offers of social support during a stressful situation (see Fig 20.1 ) Ignored meant that the subject did not look at or made no verbal acknowledgment of the confederate; acknowledgment meant some brief comment or a head nod was given in response to offers of support; and accepted meant the subject was very responsive

to crowding report feeling a greater sense of powerlessness over their living environments than their less crowded counterparts (Baum & Valins, 1977, 1979; Baron et al., 1976; Carr, Hopper & Ruback, 1986; Saegert, 1978) Sherrod (1976), Aiello, DeRisi, Epstein, and Karlin (1977), Evans (1979), Nicosia et al (1979), and Doofey (1978) all found negative aftereffects immediately following laboratory exposure to crowded conditions Sherrod, Evans, and Nicosia and colleagues each utilized the Glass and Singer (1972) aftereffects paradigm that measures persistence on challenging puzzles Giving up sooner in the face of challenge in an achievement context may be indicative of greater helplessness (Cohen, 1980; Glass & Singer, 1972) Dooley (1978) incorporated proofreading performance as her aftereffects measure Saegert, Mackintosh, and West (1975) reported that crowded train stations produced negative aftereffects in women only Nicosia's data also indicated more severe aftereffects of crowding among women

Parallel trends to the laboratory work have been noted in studies of more chronic, crowded living conditions, finding less persistence on difficult puzzles among persons living in more crowde.d neighborhoods (Fleming, Baum, & Weiss, 1987) Moreover, perception of control over social

interactions largely accounted for the main effect of neighborhood crowding

on the helplessness indicator Residents of crowded dorms feel less control over social interaction than their uncrowded counterparts (Baum & Valins,

1977, 1979) exhibit behavioral strategies in a group' prisoners' dilemma game consistent with helplessness (Baum, Aiello, & Calesnick, 1978; Baum, Gatchel, Aiello, & Thompson, 1981) Interestingly, the development of helplessness strategies in the game over the course of the initial semester under crowded conditions was mirrored by residents growing external attributions for problems in the dormitory over this same time period (Baum

et al., 1981) Uncrowded residents generally felt self-efficacy over problems

in their dormitory over the course of the semester and these internal

attributions remained stable over time Crowded dormitory residents are also less likely to seek clarification when given ambiguous instructions about

an impending laboratory procedure than were uncrowded dormitory

residents

Traffic congestion also is related to motivational deficits Greater traffic congestion levels have been related to decreased task motivation on

challenging puzzles and proofreading (Novaco et al., 1979; Schaeffer et al., 1988; D Stokols, et al., 1978)

The most direct evidence for helplessness induced by crowding comes from

a pair of studies on residential crowding and children by Rodin (1976) Matched on socioeconomic indicators, elementary-aged schoolchildren living

in more crowded public housing were less likely to control the administration

of outcomes in an operant conditioning paradigm in comparison to their less crowded counterparts In a second study, helplessness was induced in adolescents by a classic helplessness paradigm, pretreatment with an insoluble versus a soluble puzzle Helplessness was monitored on a second challenging but solvable puzzle The main effect of pretreatment solvability (the helplessness induction) was significantly moderated by residential crowding with heightened vulnerability to the induction of helplessness among the more crowded children In their study of children in India, Evans,

et al., (1998) replicated Rodin's effects (but for girls only) Saegert (1982), however, did not replicate these findings examining a sample of children from public housing projects in New York City

Summary

Residential crowding has little impact on physical morbidity among the general population Residential crowding may be linked, however, to ill health among vulnerable subgroups of the populations, particularly young children and extremely crowded, captive populations (e.g., prisons, refugee camps) Evidence linking high density exposure either under controlled conditions or in the field to elevated cardiovascular functioning is quite strong Neuroendocrine functioning also appears elevated, although less data are available The potential clinical implications of these two data patterns has not been explored in the crowding literature

Psychological distress is increased by residential crowding Individual but notaggregate level analyses continue to uncover a positive association betweencrowded living conditions and poorer psychological health Several studies have excellent controls for sociodemographic factors and one is a

prospective, longitudinal analysis Psychological distress associated with residential crowding may be caused by a typical coping strategy for dealing with chronic high density living conditions-social of this social withdrawal may be a breakdown in socially supportive relationships There is not strong evidence, however, that human crowding is associated with more extreme forms of psychopathology characterized in some animal studies as a

behavioral sink

There is also evidence that crowding may lead to the development of motivational deficits, particularly among children in achievement-related contexts There is indirect evidence suggesting that these motivational deficits are related to learned helplessness from diminished perceived control over the environment

NOISE

Noise, which is defined as unwanted sound, is typically measured in

decibels Decibels is a logarithmic scale with a

Physical Health

Studies have examined exposure to either occupational noise or community noise and disease Outside of cardiovascular problems, there appears to be little relation between noise exposure and physical disease In industrial settings, noise has been associated with increased risk for myocardial infarction (Ising, Babisch, & Giinther, 1999), reductions in cardiorespiratory efficiency (Semczuk & Gorny, 197 l), difficulties in peripheral circulation and cardiac problems generally (Jansen, 1961), electrocardiogram abnormalities suggestive of coronary heart disease (Cuesdan general sickness- related absenteeism (Cohen, 1973), and self-reported fatigue (Carlestam, Karlsson &Levi, 1973; Melamed & Bruhis, 1996) Several industrial studies have found

no associations between occupational noise exposure and rates of coronary heart disease (Lees, Romeril, & Wetherall, 1980) or rates of total illness (Lees et al., 1980)

Community airport noise studies have shown that higher levels of noise exposure are associated with greater contact with physicians for coronary-related problems (Knipschild, 1977a) and, for women only, use of drugs to treat hypertension (Knipschild & Oudshoorn, 1977; Koszarny, Maziarka, & Szata, 1981) These studies also show an association with greater physician contact in general (Knipschild, 1977b), rates of colds (Ising et al., 1990), as well as total health symptoms (Pulles & Stewart, 1990), and higher levels of coronary heart disease symptoms among women but not men (Koszarny et al., 1981) Graeven (1974) and Hiramatsu, Tamamoto, Taira, Ito, and

Nakasone (1993), however, found no differences in self-reported health symptoms between persons living in airport impact zones versus citizens in quiet neighborhoods

Turning to road traffic noise, Cameron, Robertson, and Zaks (1972) found little relation between community noise levels (self-reported) and illness rates Babisch, Elwood, Ising, and Kruppa (1993) found slight elevated risk (1.2 odds ratio) in noisier traffic areas in three different sites for men

residing in areas above 65 dBA Leq However, when comparing across different noise levels varying from > 50 dBA Leq to 70, they uncovered no linear relation

Another area of physical health worthy of note in the noise literature is birth defects and other abnormalities during pregnancy Not surprisingly, findings

in this area are highly controversial and not at all definitive Jones and Tauscher (1978) found higher rates of birth defects in high airport noise impact zones relative to quieter areas, but Edmonds, Layde, and Erickson (1979) could not replicate the findings Several rodent studies have found abnormal fetal development following noise exposure (Welch, 1973) There

is evidence that women working under very noisy conditions, particularly if subjected to additional stressors like shiftwork, have more pregnancy complications such as vaginal bleeding and pregnancy- induced

hypertension (Nurminen & Kurppa, 1989) Babies born in areas with high noise impact have lower birth weights (Ando & Hattori, 1977; Knipschild et

al (1981) with controls for socioeconomic status Ando (1987) also found an increase in low birth weight babies following the opening of a new airport Schell (1981) also noted that female infants, but not males, had significantlyshorter gestation periods in high airport noise impact zones Moreover, Andoand Hattori (1977) showed diminished levels of human placental lactogen levels in mothers living in high noise airport impact zones Finally, Schell andAndo (1991) found a dose- response function relating airport noise levels and 3-year-olds' physical stature (but not weight) in a large epidemiological study The data on possible linkages between noise and early development are sobering to consider in light of environmental surveys of neonatal, intensive care units that are often populated by premature babies Levels of noise match or exceed recommended standards for ambient traffic exposureand health (Lawson, Daum, & Turkewitz, 1977)

Psychophysiogical

Although previous reviews of noise indicate that cardiovascular responses (typically blood pressure or pulse) to noise under acute exposures rapidly habituate (Glass & Singer, 1972; Kryter, 1994), more careful scrutiny of this literature indicates important exceptions Persons who are noise sensitive donot easily habituate (Conrad, 1973; Stansfeld & Shine, 1993), nor do

individuals who are hypertensive (von Eiff, Friedrich, & Neus, 1982) term habituation is blocked when people perform demanding cognitive tasksunder noise (Carter & Beh, 1989; Conrad, 1973; Mosskov & Ettema, 1977) Evans et al (1996) also showed that noise significantly increases blood pressure over a 20-minute period without habituation, if it follows exposure

Short-to a psychological stressor (i.e., giving a speech, taking a final examination).Other psychophysiological indices examined under acute noise have

included electrodermal activity, ECG, EEG, and neuroendocrine activity Results parallel the cardiovascular data, indicating rapid habituation (Finkle

& Poppen, 1948; Fruhstorfer & Hensel, 1980) Recent findings suggest, however, that when short-term exposure to loud noise is accompanied by demanding tasks, habituation may be blocked (Frankenhaeuser & Lundberg, 1977; Ising, Rebentisch, Poustka, & Curio, 1990; Lundberg &

Frankenhaeuser, 1978) Work by Tafalla and Evans (1997) indicated a centralrole of effort in the performance/physiological activation tradeoff

Performance can be maintained, at least under many circumstances (e.g., short-term tasks that do not demand large amounts of attention or

memory), by additional cognitive effort Such maintenance of performance, however, appears to exact a cost of greater psychophysiological