East-West Environment and Policy Institute Research Report No. 14

Conceptual Approaches to Human Ecology by A. Terry Rambo

East-West Center ISSN-0739-6716

Honolulu, Hawaii

T H E EAST-WEST CENTER isaneducational institution establishedin Hawaii in 1960 by theUnited StatesCongress. TheCenter'smandate is"to promote better relations and understanding among the nations of Asia, the Pacific, andthe United States through cooperative study, training, andresearch." Each year nearly 2,000 graduate students, scholars,professionals in business and government, andvisiting specialists engage in research with the Center's international staff o n major issuesand problems facingtheAsianandPacific region.Since 1960, more than 30,000 men and w o m e n from theregion have participated inthe Center's cooperative programs. The Center'sresearchand educational activities are conducted in five institutesCommunication, Culture Learning, Environment and Policy, Population, and Resource Systems—and inits Pacific \s\ands Development Program,O p e n Grants, and Center-wide programs. Although principal funding continuestoc o m e from theU.S. Congress, more than 20 Asian and Pacific governments, aswell as private agencies and corporations, have provided contributions for program support. The East-WestCenter isa public, nonprofit corporation withan international board ofgovernors. T H E EAST-WEST E N V I R O N M E N T A N D POLICY INSTITUTE was established in October 1977to increase understanding of the interrelationships among policies designedto meet abroad rangeofhuman and societal needsovertime andthenatural systems and resources o n which these policies depend or impact. Through interdisciplinary and multinational programs of research, study, and training, the Institute seeksto develop and apply concepts andapproaches useful in identifying alternatives available to decision makers andin assessingthe implications of such choices. Progressand results of Institute programs aredisseminated inthe East-West Center region through research reports, books, workshop reports, working papers, newsletters,and other educational and informational materials. William H .Matthews, Director East-West Environment and PolicyInstitute East-WestCenter 1777 East-West Road Honolulu, Hawaii 96848

Conceptual Approaches to Human Ecology by A. Terry Rambo

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Research Report No. 14• June1983 East-West Environment and Policy Institute

A . T E R R Y R A M B O is a research associate and coordinator of the H u m a n Interactions with Tropical Ecosystems P r o g r a m A r e a at the E n v i r o n m e n t and Policy Institute, Easi-Wesi Center, H o n o l u l u , H a w a i i . Before j o i n i n g E A P I , Dr. R a m b o was a lecturer at the U n i v e r s i t y of M a l a y a in K u a l a L u m p u r and a visiting professor ai the Dalat U n i v e r s i t y Graduate School of Politics and Economics in S a i g o n , V i e t n a m .

LibraryofCongressCataloginginPublication Data Rambo. A. Terry Conceptualapproachesto humanecology. (Research report / Easi-Wesi Environment and Policy Institute; no. 14) Bibliography: p. I. Human ecology—Philosophy. I.Tiile II.Scries: Research report [East-West Environment and Policy [nstitute(Hono)ulu, Hawaii)!; no. l-t. GF21.R35 1983 304.2 83-16460 ISBN 0-86638-049-3

CONTENTS ACKNOWLEDGMENTS

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ABSTRACT INTRODUCTION T H E ORIGINSOF H U M A N ECOLOGY ENVIRONMENTAL DETERMINISM E N V I R O N M E N T A L POSSIBILISM T H E C O N C E P T O FC U L T U R A L E C O L O G Y T H EECOSYSTEM-BASED M O D E L OFH U M A N ECOLOGY T H E ACTOR-BASED M O D E L OFH U M A N ECOLOGY THE SYSTEMS MODEL OFH U M A N ECOLOGY CONCLUSION BIBLIOGRAPHIC NOTE REFERENCES

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1 2 3 4 6 13 18 23 29 31 33

Table Table 1.

C o m p a r i s o n o f the C u l t u r a l Ecology-ofJ a v a and the O u t e r Islands of Indonesia

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Figures Figure 1. T h e model o f environmental determinism

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Figure 2. T h e model of environmental possibilism

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Figure 3. Figure 4. Figure 5. Figure 6.

© 1983 East-West Center. East-West Environment and PolicyInstitute. All rightsreserved. Printed in the UnitedSlatesof America.

T h e model o fcultural ecology T h e ecosystem-based model of h u m a n ecology T h e actor-based model o f h u m a n ecology Social system-ecosystem interactions

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ACKNOWLEDGMENTS T h i s research report is a revised and expanded version o f my paper, " T h e Development o f a C o n c e p t u a l Framework for H u m a n Ecology," w h i c h was issued i n 1979 as W o r k i n g Paper N o . 4 by the Department o f A n t h r o p o l o g y and Sociology of the U n i v e r s i t y o f M a l a y a . T h e first draft o f the paper was written i n 1978 while I was a visiting research fellow at the East-West E n v i r o n ment and Policy Institute, H o n o l u l u , H a w a i i . Discussions o f h u m a n ecology concepts with several E A P I staff members and fellows, particularly W i l l i a m H . M a t t h e w s , R i c h a r d A . Carpenter, Lawrence S. H a m i l t o n , and A n d r e w P. V a y d a , greatly helped me to clarify my t h i n k i n g about the several models described. C o m m e n t s by H a r o l d M c A r t h u r , Peter P r i c e , and Percy E . Sajise led me to make further revisions i n this presentation. T h e field research that provided the e m p i r i c a l basis for development o f the systems model of h u m a n ecology was supported by two successive Southeast A s i a Research Fellowships awarded by the F o r d F o u n d a t i o n and by several staff research grants from the U n i v e r s i t y o f M a l a y a . T h e c o n t i n u i n g support given to this work by Professor Y i p Yat H o o n g , the former deputy vice chancellor for research at the U n i v e r s i t yo f M a l a y a , is gratefully acknowledged.

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M y intellectual debts i n the field o f h u m a n ecology are m a n y but special m e n t i o n must be made o f the influence o f E l m a n R . Service, E r i c R . Wolf, a n d H e n r y T. L e w i s . C o n t i n u i n g discussions with A l i c e G . Dewey, K a r l L . Hutterer, Jeff R o m m , and N e i l L .J a m i e s o n III have also contributed to the achievement of such coherence as the t h i n k i n g incorporated i n tKis report may exhibit.

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ConceptualApproaches to HumanEcology

by A . Terry Rambo

ABSTRACT A number o f very different conceptual approaches have been employed i n h u m a n ecology. T h i s report reviews several o f the most important analytic frameworks: environmental determinism and possibilism, cultural ecology, the ecosystem-based m o d e l , and the actor-based model. T h e contributions made by each conceptual approach to increasing understanding of h u m a n ecology are described, a n d their strengths and weaknesses are assessed. F i n a l ly, an alternative conceptual approach—the systems model o f h u m a n ecolo g y — i s proposed. In this interactive model, the h u m a n social system is seen as being linked to its ecosystem through the interchange o fenergy, materials, and information.

INTRODUCTION H u m a n ecology, most broadly defined as the study o f h u m a n interactions with the environment, has in recent years gained greatly increased attention i n all o f the social sciences. Despite this, there appears to be little consensus as to what h u m a n ecology actually is or should be. In particular, there is c o n t i n u i n g vigorous discussion about the suitability of a p p l y i n gseveral different theoretical approaches in understanding human-environment interactions. W h / i e such diversity o f viewpoints within a scientificdisciplinemay indicate youthful vigor, it also can present the nonspccialist with severe obstacles to g a i n i n g an understanding o f the overall form and direction o f the field o f study. T h i s problem is made even more acute by the often polemiccharacter o f programmatic statements regarding the nature o f h u m a n ecology. M a n y writ-

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ers approach theoretical discussions as i fthey are dealing with theology, advocating their o w n models as the only true and correct ones while dismissing other conceptual approaches as archaic, wrong-headed, or even i m m o r a l . S u c h out-of-hand dismissal may on occasion be deserved but also tends to obscure the existence o f legitimate alternative conceptual approaches. In this report, alternative conceptual models o f h u m a n relations with the environment are described in the historicalorder i n w h i c h they have appeared in the scientificliterature. Such a chronologicalapproach helps to illustrate the interplay between research results and the formulation o f new theoretical concepts. N o superiority is imputed to more recently developed paradigms. In fact, certain currently popular models may be viewed as regressive from the standpoint o f the development ofsocial science theory as a whole. A l t h o u g h largely discredited a m o n g social scientists, classical and early m o d e r n theories o f environmental influence on h u m a n affairs (determinism and possibilism)are often employed by historians. M o s t notable o f such historians is A r n o l d J . Toynbee, who advocates a possibilist stance i n his influential A Study of H i s t o r y . T h e model of cultural ecology proposed by J u l i a n Steward is still the g u i d ing p a r a d i g m for m a n y investigators, but in recent years it has been challenged by the ecosystem-based model first proposed by A n d r e w P. Vayda a n d Roy A . Rappaport. T h e i n d i v i d u a l d e c i s i o n - m a k i n g characteristic is the focus o f actor-based models o f h u m a n ecology, and the systems model o f h u m a n ecology stresses investigation o f interactions between h u m a n social systems and ecosystems based on their reciprocalexchange o fenergy, materials, and information.

THE ORIGINS OF HUMAN ECOLOGY Since ancient limes there have been m a n y attempts to explain events i n terms o f environmental influences o n h u m a n behavior. Astrology represents one early system o f thought relating environmental forces to h u m a n actions. A l t h o u g h wholly discredited as a scientific theory by modern astronomy, the belief that the movement o f the stars controls h u m a n destiny retains a strong hold o n the popular i m a g i n a t i o n , as evidenced by the appearance o f astrological advice c o l u m n s i n m a n y daily newspapers. In a vein more compatible with m o d e r n scientific thought, the ancient G r e e k philosophers recognized that m a n was both influenced by nature and a force for change i n the environment. It was suggested, for example, that the different forms o f political organization o f the G r e e k city states a n d the Eastern empires reflected the influences o f climate on the personalities o f their citi-

ConccpiuaJ Approaches w Human Ecology

zens. T h i s theme later was developed by M o n t e s q u i e u and other French writers o f the Enlightenment and advocated i n recent times by the A m e r i c a n geographer Samuel H u n t i n g t o n . O t h e r classical writers commented on the destruction o f the natural landscape of A t t i c a and N o r t h A f r i c a resulting from deforestation and o v e r g r a z i n g , a theme taken up i n the mid-1800s by George P. M a r s h , whose book, M a n a n d N a t u r e , or, P h y s i c a l Geography as M o d i f i e d by H u m a n A c t i o n was a precursor of the ecologicalcatastrophe writings so popular recently. These early writings, however, were generally anecdotal rather than presenting a coherent theory o f human-environment relationships. It was only with the development o f geography and anthropology as scientificdisciplines in the latter part of the nineteenth century that h u m a n ecology became the subject ofsystematic study. T h e first theoretical approach to be tried, however, was that of environmental d e t e r m i n i s m — a false start that greatly retarded subsequent development o f h u m a n ecology.

ENVIRONMENTAL DETERMINISM A r o u n d the turn o f the century, geographers, notably F r i e d r i c h Ratzel i n G e r m a n y and his A m e r i c a n disciple, Ellen C . Semple, espoused the view that h u m a n s were completely the product of their e n v i r o n m e n t , a theory that came to be called environmental d e t e r m i n i s m . Followerso f this school, which d o m i nated geographical thought well into the 1920s, asserted that all aspects o f h u m a n culture and behavior were caused directly by environmental influences ( F i g u r e 1). F o r example, the British were a nation o f seafarers because they were an island-dwelling race surrounded by seas; the A r a b s were monotheistic M u s l i m s because l i v i n g i n the vast empty desert turned their minds toward a single G o d ; the E s k i m o s were p r i m i t i v enomads because the harsh conditions o f their arctic habitat forbade their development into a complex c i v i l i z a t i o n . T h e books o f Semple and others were filled with endless listings o f seemingly plausible environmental determinants o f cultural forms. A l t h o u g h seductive when first encountered, such claims o f causal correlation between environment and culture were easily refuted once given careful consideration. F o r example, the Tasmanians, w h o lived on an island not unlike the one inhabited by the E n g l i s h , made no ships; the A r a b tribes who had wandered that vast lonely desert for thousands o f years before the appearance of M u h a m m a d were believers i n a large pantheon of spirits; and the icy wastes once traversed by E s k i m o d o g sleds are now the scene o f snowmobile races alongside giant oil pipelines. T h e r e is s i m p l y too m u c h variation in h u m a n behavior i n seemingly s i m i l a r geographical settings for it t o be environmentally determined.

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Conceptual Approaches to Human Ecology

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CULTURAL CULTURALFORM TRAITS

MENTAL

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Figure 1.The model of environmental determinism.

ENVIRONMENTAL POSSIBILISM In place o f the discredited d e t e r m i n i s m , a new theory, called environmental possibilism, was proposed. Its proponents asserted that while the environment did not directly cause specific cultural developments, the presence or absence of specific environmental factors placed limits on such developments by either p e r m i t t i n g or forbidding their occurrence (Figure 2). T h u s , island peoples could be seafarers, but residents o f Inner M o n g o l i a could not be; inhabitants of temperate regions might practice agriculture, but those l i v i n g in arctic latitudes c o u l d not. T h e value o f the possibilist approach was perhaps best demonstrated by the A m e r i c a n anthropologist A . L . Kroeber, who showed that the Indians o f northwestern N o r t h A m e r i c a could not adopt maize agriculture from their southern neighbors because the frost-free g r o w i n g season i n their region was shorter than the four months required for the maize plants to reach maturity. T h e i r environment thus limited the ability o f their culture to evolve in an agricultural d i r e c t i o n . A possibilist stance was also taken by the British historian A r n o l d Tbynbee in his m u l t i v o l u m e d A Study of H i s t o r y (1947), i n which he argued that the development of civilizations could be explained i n terms o f their responses to e n v i r o n m e n t a l challenges. C u l t u r e s located i n the benign tropics failed to evolve because they were not sufficiently challenged by their environment;

SCREEN

Figure 2. The model ofenvironmental possibilism.

those in extremely harsh habitats such as the E s k i m o s i n the arctic remained forever primitive because simply c o p i n g with the demands of their e n v i r o n ment sapped allo f their creative energies. O n l y those cultures in environments offering sufficient but not excessive challenges had the possibility of progressing to higher stages of c i v i l i z a t i o n . Possibilism suffers from one o v e r r i d i n g defect as a scientific theory; it lacks any general predictive or explanatory power since it is able to explain only why certain developments could not occur i n certain environments. It is totally unable to predict whether or not they would occur under favorable circumstances. F o r example, the failure o f Eskimos to grow corn is explainable, but possibilismcannot explain why the English were great seafarers while the Tasmanians were not. Clearly, the difference in the latter case was due to existence o f very different cultural traditions and bodies o f technological knowledge rather than reflecting environmental influences. In short, as the British anthropologist D a r y l l Forde concluded i n his book, H a b i t a t , Economy a n d Society (1934), which was perhaps the last major scientific exploration o fpossibilism, "between the physicalenvironment and h u m a n activity there is always a m i d dle term, a collection o f specific objectives and values, a body o f knowledge and belief: i n other words, a cultural pattern." W i t h this realization, social scientists tended to turn from studying h u m a n interactions with the environment, preferring instead to focus on the seemingly more profitable study o f the internal structure a n d functioning o f cultural and social systems. F o l l o w i n g the French sociologist E m i l e D u r k h e i m ' s i n j u n c t i o n that "social facts" could be explained only i n terms of other social facts, cultural development was explained by the concept o f diffusionism—the

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Conceptual Approachesto Human Ecology

historical spread o f traits from one culture to others, without reference being made to possible environmental influences on the process. It was not until the 1950s that social scientists, acting under the influences o f J u l i a n Steward's concept o f cultural ecology, again turned serious attention to the study of h u m a n interactions w i t h the e n v i r o n m e n t .

TRAIT DIFFUSION FROM OTHER SOCIETIES

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THE CONCEPT OFCULTURAL ECOLOGY A l t h o u g h his first papers on the subject were published in the early 1930s, it was not u n t i l the mid-1950s that J u l i a n Steward's concept of cultural ecology began to exert a significant influence i n A m e r i c a n anthropology. A l t h o u g h he was trained i n the diffusionist school, Steward's experience o f field work a m o n g the Shoshone hunters a n d gatherers i n the G r e a t Basin o f N o r t h A m e r i c a had led h i m to recognize that ecological adaptation had played at least as significant a role as diffusion i n the formation o f Shoshone culture. D r a w i n g on the theoretical methods that biological ecologists were then develo p i n g to study the adaptation o f a n i m a l species, i n particular relating specific organs to specific features o f the e n v i r o n m e n t , Steward attempted to explain certain structural aspects o f Shoshone culture i n terms o f the resources available i n the impoverished semidesert habitat. In what is still one of the finest ethnographies ever published, Steward (1938) made a c o n v i n c i n g case that the low density o f the Shoshone population, its organization into small family bands with highly dispersed and flexible residence patterns and lack o f territoriality, and the lack o f powerful permanent leaders all reflected the inability o f Shoshone technology to extract a large and stable supply of food from the thinly scattered a n d sporadicallyavailable resources o fthe a r i d e n v i r o n m e n t . It was Steward's view that not all aspects of Shoshone culture could be explained i n ecological terms—many traits were present as simply the accidental result o f diffusion from neighboring tribes—but that only some elements, w h i c h he labeled as "the cultural core," had adaptive significance. In particular, he thought technology, economics, population, and social organization were likely to be part o f the core, although he insisted that it was necessary to demonstrate this empirically in each case. H e tended to give special emphasis to the relationship between technology and the environment i n his model o f cultural ecology(Figure 3).* *lt is interesting to notethat E. E. Evans-Prifchard, • leading British social anthropologist, suggested a similar ecological approach at almost the same time as Steward although neither man appears to havebeeninfluenced by the other'swork. Pritchard (19+0)related the'settlementpatternofthe Nucr pastorialisisof the Sudan to seasonalchangesin resourceavailability. Despitethe acclaim that his monograph met from his colleagues, Pritchard's ecological approach was not emulated by themand British socialanthropologistswerenot to becomeinvolvedagain in human ecologyresearchuntil muchlaterthantheAmericans.

LANGUAGE

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Figure 3. The model of cultural ecology.

T h e A m e r i c a n anthropologist Clifford G e e r t z (1968) has applied Steward's concept o f cultural ecology to e x p l a i n i n gthe great demographic disparity that exists between J a v a and the outer islands of Indonesia. J a v a is one o f the most densely populated regions in the w o r l d , with an average density o f480 persons per square kilometer ( k m ) but with more than 2,000 p e r s o n s / k m i n some parts of the island. In m a r k e d contrast, most of the outer islands (e.g., S u m a tra, K a l i m a n t a n , T i m o r ) are characterized by densities o f less than 25 pers o n s / k m ' . Geertz has suggested that these various population densities reflect 1

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the differing agricultural adaptations employed i n the two regions, which i n turn relate to their differingenvironments (Table I). T h e topography of J a v a is one o f relatively y o u n g volcanic mountains surrounded by a series o f gently sloping basins, which offer ideal conditions for construction of irrigated fields. T h e relief o f the geologically older outer islands is generally low and irregular, offering few opportunities for development of large, gravity fed irrigation systems. T h e rivers there also tend to be slow m o v i n g , capable o f c a r r y i n g only light sediment loads. In J a v a , on the other hand, the rivers are short and fast m o v i n g , c a r r y i n g large quantities of nutrient-rich sediments from the fertile y o u n g soilso f the volcanicslopes d o w n into the paddy fields. In conformity with these environmental factors, J a v a is predominantly a region o f s a w a h irrigated wet rice agriculture while l a d a n g shifting cultivation is the principal technology employed i n the outer islands. L a d a n g , or " s w i d d e n " agriculture as it is usually called by anthropologists, is a system i n which the farmer cuts a plot of land in the forest, allows the vegetation to d r y and then burns it before planting a crop. After one or, at most, two harvests, fertility is exhausted and the plot is abandoned and a new field is cleared in the forest. T h e abandoned plot is gradually rcoccupied by forest vegetation, and after ten to fifty years it may again be cleared and farmed. S w i d d e n i n g represents an effective adaptation to f a r m i n g the impoverished soils o f tropical rain forest areas where most o f the available nutrients are stored i n the vegetation, It gives high yields with relativelylowh u m a n labor inputs since most of the work is done by the fire, which simultaneously clears the field, releases the stored nutrients back to the soil i n the form o f ashes where they are readily available to the g r o w i n g crops, and kills off pests a n d weed seeds that w o u l d compete with the crops. T h e major l i m i t a t i o n o f swidden agriculture is that a large quantity o f land is required to support each farmer. A n i n d i v i d u a l farmer requires not only the plot currently under cultivation but also a reserve o f forest land adequate for the needs o fcultivation until the old plots are again ready for clearing. S w i d d e n i n g can thus support only populations at densities o f fewer than 200 p e r s o n s / k m . If population should increase, it is necessary to shorten the forest fallow cycle, causing r a p i d destruction o f the productive capability o f the land due to erosion and nutrient loss. 3

In contrast to the impermanence a n d instabilityo f the l a d a n g systems, sawah agriculture is noted for its stability and durability. O n c e an irrigated paddy field has been constructed it can be farmed year after year for centuries with little evident loss i n productivity. T h i s reflects the fact that it is the supply o f water rather than the quality o f soil that is the most important factor i n growing wet rice. M o r e o v e r , the yield is strongly influenced by the amount of h u m a n labor put into w o r k i n gthe crop—transplanting rather than sowing the seed by broadcasting, more careful and frequent weeding, and cleaning and maintenance o f irrigation channels all contribute to a higher yield o f rice per

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hectare. Such a system may encourage population increase, since the more children (he parents have, the more hands they have to help work their paddy field. T h u s , the existence o f these radically different systems o f agriculture, reflecting different ecological conditions, may contribute to the demographic disparities between J a v a and the outer islands. Steward's concept o f cultural ecology has proved to be a powerful and effective strategy for h u m a n ecological research, offering new understanding of how traditional societies arc effectively adapted to their environments, lis successes have been achieved p r i m a r i l y in studying small-scale, primitive societies, however, especially those where a stable relationship has been established between a static population and an u n c h a n g i n g environment. T h e concept has been much less applicable to complex modern societies where the actions o f large h u m a n populations are p r o d u c i n g rapid environmental change with consequent need for rcadaptation o f the cultural core. A s conceived by Steward a n d used by others, the cultural ecology model lacks any systematic conceptualization of the environment or o f the ways in which h u man activities impinge on it. T h u s , its emphasis is almost exclusively on the h u m a n side of the human-environment equation, focusing on the adaptation of culture to nature while i g n o r i n g environmental change i n response to h u man intervention. T h i s fundamental weakness o f the concept of cultural ecology is revealed i n the work o f M a r v i n H a r r i s , an A m e r i c a n anthropologist who has incorporated this approach into studies o f what he refers to as " t c c h n o - c n v i r o n m e n i a l determ i n i s m . " O p e r a t i n g under the assumption that the technological means of adaptation to the environment is the prime mover o f cultural evolution, H a r ris asserts that the forms taken by all other aspects of culture are determined by the relationship between technology and the environment. In a widely cited paper, " T h e C u l t u r a l Ecology of India's Sacred C a t t l e " (1966). H a r r i s argues that, contrary to the accepted view t h a t H i n d u s keep excessive numbers o f useless cattle because o f their religious belief that cattle are sacred, these cows are actually extremely important to the economic welfare o f the poor peasants, helping them to make m a x i m u m use o f the scarce resources o f their e n v i r o n ment. Therefore, he concludes, the religious beliefs must have been caused by techno-cnvironmental factors. A c c o r d i n g to the conventional view, between one-third and one-half o f the 80 m i l l i o n cows i n India should be eliminated as economically wasteful animals. Because they arc so badly nourished, not more than one cow i n two yields any m i l k , and cattle wander freely a r o u n d the landscape, d a m a g i n g crops and interfering with traffic. In some areas cattle actually compete with humans for food, being kept i n special bovine old-age care shelters until they die, since the H i n d u concept o f a h i m s a that regards all life as sacred forbids their being slaughtered. Hence, it is c o m m o n l y said that this is an example of

Conceptual Approachesto Human Ecology

religious ideology interfering with the efficient ecological adaptation o f a c u l ture. H a r r i s claims, however, with some justification, that conventional analyses of the economics of Indian cattle have overlooked numerous benefits thai the seemingly excess animals provide to the peasant population. First, he reminds the reader that cows are necessary to produce bullocks, which are the m a i n draft a n i m a l on Indian farms. It is only by having large numbers of cows that the d e m a n d of the farmers for bullocks can be met. Second, cows yield a steady supply of d u n g , and cow d u n g is the main source of fuel for domestic cooking fires in m u c h of South A s i a . A c c o r d i n g to one estimate, the energy value o f the 300 m i l l i o n tons of d u n g burned each year i n India is equal to 35 m i l l i o n tons of coal. M u c h o f the rest of the d u n g is used as manure in the fields. T h e hides salvaged from deceased cows also provide the basis o f a large leather industry, which provides a livelihood for m a n y lower-casle families. Not only does H a r r i s show that the cows provide m a n y valuable economic benefits to the Indian peasants, he also argues that they do so at m i n i m a l cost to the h u m a n population. H e claims that cows rarely compete directly with people for food since they are not fed grain or fodder g r o w n on land that could otherwise grow food for h u m a n c o n s u m p t i o n , as is the case in Western countries. Instead, the cattle wander grazing freely on whatever grass they can find g r o w i n g beside roads, a r o u n d telephone poles, and between the ties on railroad tracks. T h e y also arc allowed to graze on the stubble left i n grain fields after the harvest. In other words, the cows capture otherwise unutilized energy and nutrients i n the e n v i r o n m e n i and convert these into bullocks, m i l k , d u n g , and hides—all resources o f great value to the peasants. Therefore, H a r r i s concludes, far from the keeping o f cows being caused by religious irrationality, the religious tabu on k i l l i n g cattle exists as an expression of the ecologicalvalue o f cattle to the Indian h u m a n population. H a r r i s ' paper has been subject to severe criticism on e m p i r i c a land theoretical grounds. It has been pointed out that he tends to overestimate the benefits that people derive from the cows while understating the costs of keeping such large herds. In particular, it has been claimed that 5 percent of the arable land in India is i n fact used as pasture and for g r o w i n g fodder to feed cattle, so these animals do i n fact compete directly with humans for food. It has also been argued that a smaller n u m b e r of belter fed animals w o u l d provide the same or better level of services to the h u m a n population at less economic cost. O n the theoretical side, it must be recognized that religious tabus on k i l l i n g and cons u m i n g animals arc not necessarily always as adaptive as H a r r i s seems to think. S u c h practices may, for example, appear to be ecologically rational when they first evolve, as H a r r i s has asserted to be the case with the M u s l i m prohibition on eating pork since pigs are poorly adapted to the arid e n v i r o n ment characteristic o f the A r a b i a n peninsula. O n c e i n existence, however, reli-

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gious beliefs may take on a life of their o w n and can be diffused into new environments where they may appear less rational ecologically. T h u s , M u s l i m s in Indonesia and M a l a y s i a are forbidden by their religion from eating pork although the pig is ecologically probably the most efficieni meat-producing a n i m a l that can be raised in the Southeast A s i a n tropics. Pigs are so important as a source o f protein, i n Borneo the spread o f Islam has been limited to those areas close to the coast where sufficient supplies offish are available to provide a substitute for pork. Populations on the interior side of what has been called the " p i g l i n e " nutritionallycannot afford to become M u s l i m s . T h e greatest weakness i n H a r r i s ' argument, however, is that i n focusing on the benefits that i n d i v i d u a l Indian farmers derive from h a v i n g large numbers of cows, he wholly ignores the destructive impact these animals have on the environment and the consequent l o w e r i n g o f the land's ability to support the total h u m a n population at acceptible levels. O v e r g r a z i n g has stripped most o f the u p l a n d areas o f South A s i a o f vegetative cover, and the barren soil of the hill slopes has had its structure destroyed by the impact of the cow's hooves and is highly subject to erosion d u r i n g the brief but intense monsoon rains. T h e rainwater, which was formerly trapped by tree roots and grasses and then gradually released p r o v i d i n girrigationwater to farms on the plains below duri n g the g r o w i n g season, now pours d o w n the slopes in sheets, c a r r y i n g away the topsoil and causing greai floods in the lowlands. T h a i the environmental degradation in India caused by cows exacts a heavy price in h u m a n hunger is clearly shown by the results o f an experimental reforestation program at S u k h o m a j r i in the hills north of C h a n d i g a r . T h e r e , each u p l a n d hectare that has been replanted a n d protected from g r a z i n g now yields sufficient water to irrigate two hectares o f good cropland i n the plains d u r i n g the d r y season, m o r e than d o u b l i n g the supply of food available to the h u m a n population. A s the previous discussion of the limitations o f the concept o f cultural ecology indicates, research on human-environment relations needs a conceptual framework that pays adequate attention to the possibility of environmental change a n d degradation o c c u r r i n g as a consequence o f h u m a n activities. C u l tural adaptation cannot be seen as static, something that is achieved at the b e g i n n i n g o f a culture's history and then maintained unchanging ever afterw a r d . Instead, the relationship between humans and nature is a d y n a m i c one i n which both culture and the environment continue to adapt and readapt as each changes i n response to the other's influence. It was recognition of the need for a more d y n a m i c model of the environmental side o f the relationship that Jed to formulation o f the ecosystem-based model o fh u m a n ecology.

Conceptual Approaches to H u m a n Ecology

THE ECOSYSTEM-BASED MODEL OF HUMAN ECOLOGY Basing their approach on the concept o f the ecologicalsystem that had been formulated by biological ecologists following W o r l d W a r II, A m e r i c a n anthropologists A n d r e w Vayda and R o y Rappaport suggested that instead o f studyi n g how cultures are adapted to the environment attention should be focused on the relationship of specific h u m a n populations to specific ecosystems.* In their view, h u m a n beings constitute simply another population a m o n g the many populations o f plant a n d animal species thai interact with each other and with the n o n l i v i n g components (climate, soil, water) of their local ecosystem. T h u s the ecosystem, rather than the culture, constitutes the fundamental unit of analysis in their conceptual framework for h u m a n ecology (Figure 4). C u l tural traits arc of interest only as they can be shown to contribute to the population's survival in the context o f the ecosystem. S u c h a framework, however attractive it might seem for reintegrating human ecology into general ecologicalt h i n k i n g , serves to stand anthropology on its head by emphasizing the biological survival of populations rather than the persistence of the sociocultural systems in which these populations participale. C u l t u r a l traits arc studied in terms of the possible contribution they make to a population's adaptation to its ecosystem rather than as being part of coherent systems in their o w n right, the traditional concern o f social scieniists. M o r e o v e r , research following the ecosystem-based model tends to be guided by the unspoken assumption that ifa cultural trait exists then it must somehow necessarily serve the adaptive needs of a local population. T h e ecosystem-based model of h u m a n ecology is exemplified by R o y R a p paport's well-known book. P i g s f o r t h e A n c e s t o r s (1968), in which he attempted to demonstrate how the religious rituals practiced by the T s e m b a g a tribal group o f N e w G u i n e a functioned to m a i n t a i n their population in balance with the available resources o f their environment. R e l i g i o n , an institution that Steward had largely excluded from his concept o f the ecologically adaptive cultural core, was seen by R a p p a p o r t as playing a key regulatory role in relations between the T s e m b a g a population and the other components o f their ecosystem. L i k e m a n y of the tribal groups of the central highlands of N e w G u i n e a , the T s e m b a g a employ a swidden system o f farming similar to that described by G e e r t z for the outer islands o f Indonesia. T h e p r i n c i p a l domestic a n i m a l raised by these N e w G u i n e a tribes is the pig. A c o n t i n u i n g puzzle to anthropologists has been their custom o f slaughtering animals only on ritual occasions, when hundreds o f pigs may be consumed i n only a few days, while the ' A n ecosystem consists of all (he living organisms and nonliving environmental elements (such as soil, water, and climate) (hat interact with each other within a spatially defined area.

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NEIGHBORING HUMAN POPULATIONS

-

'REGIONAL INTERACTIONS: TRADE, MARRIAGE. WARFARE. ETC

HUMAN POPULATION

ABIOTIC FACTORS (SOIL,AIR, WATER)

PLANTAND ANIMAL POPULATIONS

Figure 4. The ecosystem-based modelofhuman ecology. people go meatless for most of the rest o f the time. F r o m a nutritional standpoint, it w o u l d seem better to slaughter smaller numbers o f animals on a regular basis to ensure more frequent c o n s u m p t i o n o f protein by the h u m a n population. T h e great ritual feasts have therefore often been thought to be an example ofa maladaptive cultural trait s i m i l a r to the sacred cows of India. After spending fourteen months l i v i n g a m o n g the T s e m b a g a , Rappaport concluded that, far from being a maladaptive feature o f their culture, the ritual regulation o f pig k i l l i n g actually functions to better adapt the T s e m b a g a population to their tropical forest ecosystem. H e asserted that the ritual re-

Cunteptual Approaches in H u m a n Ideology

strictiun o f killing pigs only on certain ceremonial occasions serves to (1) maximize the supply o f protein at times when the T s e m b a g a most need it, and (2) m a i n t a i n the size of the T s e m b a g a population in balance with available resources. A c c o r d i n g tu R a p p a p o r t , the T s e m b a g a are able to raise adequate supplies of carbohydrates i n the form of sweet potatoes, taio, and sugar cane in their swidden plots, but they are chronicallyshort o f protein, particularly high quality a n i m a l protein, which is necessary to ensure good health and resilience in the face o f disease and injury. T h e fact that the limited number o f pigs that the T s e m b a g a are able to raise can be slaughtered only on ritual occasions associated with illness, battle, and the beginning a n d end o f periods o f fighting may serve therefore to ensure that protein is available i n significant quantities at precisely those times when it is most needed nutritionally. Illness, injury, wounds, and fear all place the h u m a n organism under greaicr than usual stress with consequent greater physiologicaldemand for protein, the basic b u i l d i n g block for bodily tissues. Individuals c o n s u m i n g an inadequate quantity o f protein arc unable lo produce sufficient antibodies to recover quickly from stress effects and are more likely to die from even m i n o r wounds or injuries than are better fed i n d i v i d u a l s . Even a temporary increase i n protein intake can produce dramatic recoveries a m o n g such malnourished invalids. T h u s , even though the T s e m b a g a killing of pigs is done for supernatural reasons to appease evil spirits believed to cause sickness and ensure the help o f ancestral spirits in fighting, since it occurs at times o f illness and war it may allow the human population to derive the m a x i m u m nutritional benefit from the small supply o f a n i m a l protein that their tropical forest ecosystem is capable o fp r o d u c i n g . R a p p a p o r i not only sees ritual as serving the nutritional best interests o f the T s e m b a g a population; he further claims the ritual cycle functions to maintain the population ai a density compatible with the long-term c a r r y i n g capacity o f the ecosystem by regulating die frequency and intensity with which warfare occurs. A c c o r d i n g to the cultural ground rules followed by the tribes of the N e w G u i n e a highlands, war is only permitted d u r i n g certain limited periods, the beginnings and ends o f which are signaled by great ritual pig feasts. N o group can go to war, however great the provocation, until a sufficient herd has been assembled to hold a proper feast. T h u s , the very ability of the T s e m b a g a to engage in war is determined by their ability to produce pigs, and their ability to raise pigs isdetermined by the overallstate o f their ecosystem. Warfare o f the sort practiced i n highland N e w G u i n e a until quite recently, while often more o f a ritual than a real battle, was on occasion quite a bloody affair with participating groups suffering heavy casualties. W h e n their losses became unacceptable, the contending sides w o u l d generally declare a truce. E a c h side w o u l d retreat to its o w n territory for a special ritual i n which v i r t u -

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ally all adu.li pigs i n the c o m m u n i t y were slaughtered. Some o f this meat was eaten by the T s e m b a g a , but most o f it was given to the men from n e i g h b o r i n g villages who had served as their alliesd u r i n g the fighting. D u r i n g the truce following the p i g feast, the T s e m b a g a were ritually barred from engaging i n new fighting. T h e y believed they had not yet repaid their ancestral spirits for the help given to the l i v i n g d u r i n g the just-concludedr o u n d of fighting and therefore they could not rely on their help again should new fighting begin. It was only after they held a second, larger festival involving the slaughter o f hundreds of pigs that their debt w o u l d be considered paid and the ancestral spirits again thought w i l l i n g to help them. A t that point warfare would again be ritually permitted. But h a v i n g slaughtered so m a n y adult pigs when the truce was declared, the T s e m b a g a w o u l d take m a n y years to rebuild their herd to sufficient size to hold the second feast. D u r i n g those years the h u m a n population also had time to r e b u i l d , m a k i n g up for the losses in warriors it had suffered d u r i n g the previous fighting. O n l y when both the pig population and the h u m a n p o p u l a t i o n ' h a d achieved sufficient size w o u l d the ritual cycle allow fighting to resume. R i t u a l , although triggered by the growth in the size o f the pig herd, thus served to help keep the h u m a n population of the T s e m b a g a i n balance with the limited c a r r y i n gcapacity o f their ecosystem. R a p p a p o r t ' s book is widely a d m i r e d for the ingenious way i n which he finds possible links between such diverse elements as n u t r i t i o n , health, warfare, population size, pigs, and religious ritual w i t h i n the framework o f the T s e m baga ecosystem. O t h e r researchers have raised serious questions, however, both e m p i r i c a l and theoretical, about the validity of his analysis. Margaret M c A r t h u r (1974), a leading A u s t r a l i a n nutritional anthropologist, has shown, for example, that the T s e m b a g a are the best nourished o f any highland N e w G u i n e a population yet studied, with an average daily protein intake well i n excess o f reasonable m i n i m u m daily requirements. She concludes that R a p p a port's assumption that the T s e m b a g a are highly vulnerable to the stress o f i l l ness or injury isapparently unfounded. E v e n i fT s e m b a g a invalidsw o u l d benefit from a greater intake o f protein, R a p p a p o r t presents no hard evidence that they i n fact receive it from the pigs killed at the c u r i n g rituals, according to M c A r t h u r . A s she notes, the fact that the sick person receives only the'liver as his share o f the meat does not suggest ingestion o f any very great quantity o f protein. T h e k i l l i n g o f large numbers o f pigs on festival occasions is also shown by M c A r t h u r to be an extremely inefficient way o f using the limited supplies o f protein available to the T s e m b a g a . D u r i n g the feasts, people literally gorge themselves on pork, c o n s u m i n g as m u c h as a k i l o g r a mo f meat in a single day. Since the h u m a n body cannot store protein i n excess o f its small daily requirement ofabout 50 grams, the bulk of this intake at festival times isnutritionally wasted, being simply burned as extra calories. C o n t r a r y to Rappaport's analysis, M c A r t h u r concludes the k i l l i n g o f pigs in smaller numbers at more frc-

ConccptuaJ Approaches to H u m a n Ecology

quent intervals w o u l d be more efficient from a nutritional standpoint. S u c h ' regular slaughter would also have greater ecological efficiency since it would remove pigs from the herd as soon as they reached maturity and ceased to be efficient converters of vegetable food to protein. T h e n the people w o u l d not have to support them for m a n y extra unproductive years while w a i t i n g for a large enough herd to be assembled to hold the ritual feast. F a r from m a x i m i z ing the flow o f energy and nutrients from the ecosystem to the h u m a n population, the ritual regulation o f T s e m b a g a p i g husbandry thus appears to be highly wasteful and inefficient. O f course the T s e m b a g a are not concerned with ecological efficiency; they slaughter pigs for religiousand social reasons and not because they are striving to ensure the m a x i m u m flow o f protein from the ecosystem to themselves. In particular, the mass slaughter o f pigs at the end o f a truce is intended to display the wealth and power o f the tribe to potential friends and enemies alike while e n s u r i n g the support o f both their ancestoral spirits and their h u m a n allies i n the next r o u n d o f fighting. T h e mass c o n s u m p t i o n o f pork on these occasions, however wasteful it may be from a n u t r i t i o n a l standpoint, serves the social needs o f the T s e m b a g a by p r o m o t i n g the formation of effective alliances with needed allies i n the c o m i n g war. T h e efficacy o f the ritual slaughter should therefore be assessed, not as Rappaport has done i n terms of the interaction o f the T s e m b a g a population with their local ecosystem, but-in terms of the adaptation o f the tribal society to the conflict-ridden social environment o f the N e w G u i n e a highlands. F r o m the latter perspective, it is particularly ironic that the T s e m b a g a had fallen v i c t i m to the forces of their larger social environment, h a v i n g been defeated i n battle i n 1953, driven off their ancestral lands, and forced to take refuge a m o n g their allies. A s Rappaport himself reports, "the T s e m b a g a ceased to exist as a group after their defeat, a n d , ifit were not for the agents of the newly arrived A u s t r a l i a n government who offered to protect them, it is unlikely that they w o u l d as a group have returned to their territory" (1968). S u c h a group hardly seems an appropriate choice to illustrate a theory of the role that ritual plays i n m a i n t a i n i n g homeostatic balance between a local h u m a n population and its ecosystem. To the extent that balance is m a i n t a i n e d , it w o u l d appear to be between h u m a n society i n the highlands as a whole and the regional ecosystem, not between transitory local populations like the T s e m b a g a and the small territories they exploitdirectly. Despite the m a n y serious criticismso f Rappaport's study, it remains a valuable contribution to h u m a n ecology. Perhaps its greatest impact has been to focus attention on the adaptive significance or ideology, an aspect of culture that Steward had largely excluded from consideration as affecting h u m a n interactions with the environment. B y suggesting plausible ways in which religious ritual might regulate T s e m b a g a relations with other components of their ecosystem R a p p a p o r t opened the eyes of social scientists concerned with ccol-

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ogy to a new area o f study. That his particular model of the interactions between r i t u a l , h u m a n population, and other ecosystem components may not be a valid one is a reflection on the specific conceptual approach that he employed, not a rejection of his more fundamental insight that religious ritual could be just as significant ecologically as the technological aspects o f culture that Steward emphasized.

Conceptual Approaches to H u m a n Ecology

CHOOSES

19

ADAPTIVE

INDIVIDUAL

T h e professional debates that followed publication o f Rappaport's book also have focused attention on what remains the greatest theoretical problem i n h u m a n ecological studies—that o f identification of the unit o f h u m a n adaptation to the environment. W h i l e some critics, of w h o m the present author is one, feel R a p p a p o r t erred i n t h i n k i n g too small and focusing on a local population rather than the larger social system of the highlands as his unit o f analysis, others take the position that adaptation occurs p r i m a r i l y at the level of die i n d i v i d u a l rather than at the level o f groups, populations, or social systems. It is o n the basis o f the latter convictionthat what has been called the actor-based model of h u m a n ecology has been formulated.

SUCCESS

ENVIRONMENTAL SELECTIVEFORCES

THE ACTOR-BASED MODEL OF HUMAN ECOLOGY In the face ofsevere e m p i r i c a lproblems in defining the social unit ofecological adaptation, it has been suggested that adaptation occurs at the level of individuals rather than of cultures or populations. T h i s actor-based model o f h u m a n ecology, as O r l o v e (1980) has labeled it, has become the major new wave i n h u m a n ecology. T h e model reflects both anthropologists' general concern with i n d i v i d u a l d e c i s i o n - m a k i n g processes and evolutionary biologists' current preoccupation with showing that natural selection operatesexclusively at the level o f the individual o r g a n i s m . F r o m this perspective, any higher levels o f organization, whether c o m m u n i t i e s , ecosystems, or h u m a n social systems, exist only as the fortuitous outcome of interactions a m o n g many i n d i vidual organisms. In the case of h u m a n society, therefore, environmental adaptation is seen as o c c u r r i n g not as the result o f natural selection on the cultural or social system level but rather as the result of the outcome of thousands of i n d i v i d u a l decisions about how best to interact with the environment. Individuals are assumed to be m a k i n g choices constantly about how to exploit available resources while c o p i n g with environmental hazards. Those who make the " c o r r e c t " choices will survive and prosper; those who choose less wisely will be selected against. O v e r time, the more successful adaptive strategics will become institutionalized as cultural norms. S u c h n o r m s , however, are no more than the statistical outcome of i n d i v i d u a l choices a n d have no independent reality o f their o w n as has been the usual conception o f social scientists ( F i g ure 5).

4>

ADAPTIVE STRATEGY B

INDIVIDUAL B

FAILURE

F i g u r e 5. T h e a c t o r - b a s e d m o d e l o f h u m a n ecology.

For example, an actor-based analysis o f the T s e m b a g a might explain the ritual cycle o f p i g k i l l i n g described by Rappaport as simply the accidental outcome o f hundreds o f separate decisions by i n d i v i d u a l tribesmen about how to best m a x i m i z e the use o f the limited resources available i n order to achieve power and prestige w i t h i n their society. T h u s , while the success o f the feast from the societal viewpoint is measured by the total n u m b e r o f pigs that are sacrificed, the status o f each i n d i v i d u a l T s e m b a g a male is enhanced only in direct relationship to the number o f pigs that he contributes. T h e larger the n u m b e r o f animals he can k i l l , the greater the number o f guests he can entertain and the larger the portions o f meat he is able to present to his guests, thus placing them under greater obligation to assist h i m i n the future. Each T s e m baga male therefore will seek to b u i l d up the largest herd that his family's labor force can support. O n l y when he reaches that limit will he want to hold the feast and only when a sufficient n u m b e r o f men have achieved the desired n u m b e r o f pigs will the c o m m u n i t y as a whole agree that it is time for the cerem o n i a l slaughter. It may be, as R a p p a p o r t claims, that this happens before the

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c a r r y i n g capacity o f the ecosystem is exceeded and its future productivity degraded but, from the perspective of the actor-based model o f decision making, this happy result is no more than the summed outcome of m a n y separate i n d i v i d u a l decisions. T h e actor-based m o d e l , with its emphasis on the processes by which people make decisions about how to interact with their e n v i r o n m e n t , is a valuable approach for understanding how change occurs in social systems in response to environmental perturbations. T h e approach is particularly useful for the insight it gives into why traditional farmers accept or reject agricultural innovations. A study by M i c h a e l M o c r m a n (1968) has, for example, helped to explain why peasant rice farmers in northern T h a i l a n d have adopted tractors under certain environmental circumstances while they continue to rely on water buffalo under other circumstances. Similarly, M i c h a e l C a l a v a n (1977) has shown how willingness of T h a i farmers to plant i m p r o v e d rice varieties reflects rational consideration o fenvironmental forces affecting crop yields. These and other studies of i n d i v i d u a l decision m a k i n g have shown convincingly that A s i a n peasants arc far from being the tradition-bound creatures of the economic development textbooks. Instead, they are shown to be highly rational d e c i s i o n makers who carefully assess agricultural innovations in terms of potential benefits and costs. Despite their promise o f higher yields, " m o d e r n " c r o p p i n g methods are often rejected because such innovations may require high inputs o f fertilizer, pesticides, and water. These inputs are unavailable to the poorer farmers, and modern c r o p p i n g methods are also m u c h more vulnerable to environmental hazards such as floods, droughts, and insect and disease outbreaks. Poor m a r g i n a l farmers, who arc barely able to eke out a l i v i n g with existing technology, simply cannot afford to take the greater risks of failure associated with innovative means o f production. R a t h e r than take b i g risks to m a x i m i z e income, the farmer who has only I hectare (ha) or less o f land must always seek to m i n i m i z e risks. F o r h i m it is better to obtain a harvest o f 1,000 kilograms o f padi every year without fail than it is to harvest 3,000 kilograms in favorable years and nothing i n years when environmental conditions are less favorable. F r o m this perspective, it is easy to understand why Vietnamese peasants from the R e d R i v e r D e l t a , who were notoriously conservative i n their f a r m i n g methods there, proved 1 0 be extremely receptive to agricultural innovations after their resettlement i n the M e k o n g Delta i n 1955. These peasants had not miraculously become more " r a t i o n a l " and less " t r a d i t i o n b o u n d " simply by m o v i n g from north to south; they had increased their average landholdings from .1 ha to 5 ha per family. T h e y could now afford to take the risks o f experimenting on part o f their land with " m i r a c l e r i c e " from the International R i c e Research Institute ( I R R I ) , with fertilizers, insecticides, and even tractors, because failure no longer meant starvation. U n d e r new

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environmental conditions, these formerly conservative peasants quickly became a m o n g the most innovative farmers inV i e t n a m . A l t h o u g h the actor-based model o f h u m a n ecology has been usefully c m ployed in e x p l a i n i n g peasant choices about environmental relations, it relies upon a set o f questionable assumptions about h u m a n s and society. T h e fact that T h a i peasants are capable of choosing which o f two rice varieties will give o p t i m u m yields under local environmental conditions cannot be taken as evidence that humans in general always or even usually make correct decisions about their interactions with the environment. In its assumption that humans always behave rationally, the actor-based model bears many resemblances to the "free-market" model of the classical economists who conceived of countless independent i n d i v i d u a l decisions to buy or sell as operating to produce optimal prices i n any particular supply and demand situation. M o d e r n economists have largely abandoned this free-market m o d e l , aware as they are o f the imperfections o f consumer knowledge and the deliberate manipulations by monopolistic corporate bodies, which distort the free market. Advocates o f the actor-based model o f h u m a n ecology, however, appear to be e m b r a c i n g uncritically such an " A d a m S m i t h " conceptual approach with the implicit assumption (hat i n d i v i d u a l farmers normally make their decisions in an ecologically rational way. A n d r e w V a y d a (Vayda and M c C o y , 1975), in particular, h a v i n g disavowed his earlier theoretical view that it is local populations that are adapted to ecosystems, now appears to take the position that individualsi n traditional societies generally make " c o r r e c t " decisions about the use o f natural resources so that the sum o f these decisions promotes stable e n v i r o n m e n t a l relationships. W h i l e no anthropologist doubts that traditional peoples often have accurate and detailed environmental knowledge, which can allow them to make rational decisions about resource use and c o p i n g with natural hazards, it must be strongly emphasized that there is no inherent requirement that such an end will result. In m a n y situations, such as "the tragedy ol the c o m m o n s " described by G a r r i u H a r d i n (1968), the summed effect o f i n d i v i d u a l decisions, all o f which are rational from the perspective of each actor, is to destroy the c a r r y i n g capacity o f the e n v i r o n m e n t , thus l o w e r i n g the welfare of the whole community*

"The tragedy of the commons refers to a situation where a number of individuals share unlimited access to a limited dcgraduble. resource such as a communal pasture. It is in each individual's short-term self-interest to graze as many animals as possible on the pasture, thus ensuring personal maximum gains. This quickly leads to overgrazing, which, if continued unchecked, results in the degradation of productivity of the pasture, as lias occurred in much of India. Everyone loses, but those individuals who keep the most animals on the deteriorating range s(ill maximize (heir share of the declining communal resource so that overgrazing is likely to continue until pasture is destroyed. Such a process can be observed currently in many upland areas in Asia.

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It is not even valid 1 0 assume that i n d i v i d u a l salways make rational adaptive choices in terms o f their short-run self-interest. Recent w o r l d history provides abundant examples o f people m a k i n g w r o n g choices for their o w n survival, H o w , for example, is it possible for anyone lo assert that humans are rational decision makers i n the face of evidence that d u r i n g W o r l d W a r II several m i l lion Jews in Europe went q u i c d y and w i t h virtually no resistance to the N a z i extermination camps? W h e n the Secret Police (SS) or Gestapo knocked at the door each o f these individuals made the decision to accept fate and go along peacefully—a w r o n g decision that repealed millions of times resulted i n the near extermination o f a people. G i v e n the o v e r w h e l m i n g m i l i t a r y power possessed by the N a z i s , it might have made no difference to the ultimate outcome if the J e w s had decided to resist, as they finally d i d in the Warsaw Ghetto uprising, but it is a fact that such resistance was never even considered because use o f physical force was not condoned by J e w i s h culture as it had evolved i n the ghettos of E u r o p e . T h e " g o o d m a n " was one who was peaceful and a c c o m m o d a t i n g i n the face o f force, not one who was violent and offered resistance to authority. Since individuals must make decisions w i t h i n the context of their particular culture, all choices arc ultimately value statements—the expression o f a preference for one way of life over another. Such values are, however, a property o fthe social system, not o f the i n d i v i d u a l actors within the system. A n i n d i v i d u a l T s e m b a g a tries to raise the largest possible p i g herd, not because that is the o p t i m u m strategy for adapting to the N e w G u i n e a e n v i r o n ment but because that is the way in which he can gain status within T s e m b a g a society; a T h a i farmer chooses to grow rice variety A instead of rice variety B because he believes that it will give h i m a higher yield from his land and a higher yield will allow h i m to live in the style that T h a i culture considers good. T h e i r decisions may o r may not be correct ones within the context o ftheir cultural values, but they as individuals d i d not create these values. Instead, the values arc a pre-existing aspect of the social systems into which these i n d i v i d u als were b o r n . A s children they were socialized to accept these values as correct, and as adults they make their choices about interactions with the environment in terms o f those values. T h e T h a i farmer does not try to accumulate a large herd o f pigs and the T s e m b a g a people do not try to raise a rice crop, however suitable such a strategy might be from an ecological standpoint, because such decisions arc not even options with the frameworks of their respective cultures. A T s e m b a g a is concerned with raising pigs and a T h a i with growing padi not because o f any choice made by these individualsbut because iheir respective cultures channel their interests in these directions. Both ihe nature o f the game and the rules by which it is played are set by the social system, with the i n d i v i d u a l actor being able only to choose his specific moves. T h u s , the T s e m baga may strive to raise a larger or smaller herd o f pigs and the T h a i may

Conceptual Approaches10 H u m a n Ecology

plant miracle rice seed instead o f the traditional variety—the social systems " a l l o w " the individual that much freedom of choice. Rut the larger issues o f life are not matters o f choice. H a m l e t may agonize about being and n o n b e i n g , but most individuals s i m p l y accept their existence w i t h i n an o n g o i n g social system as given. T h e y may try 1 0 better their situation, but they normally do not seek to rewrite the fundamental rules o f the game as they are prescribed by their culture. T h e actor-based model o f h u m a n ecology isthus one of limitedapplicability. It can reveal a great deal about why individualsw i t h i n a particular social system make the particular choices about interactions with the environment that they do, but ii cannot explain why their social system presents them with the particular choices it does. A n explanation of the character of a social system as a system cannot be achieved by looking al ihe characteristics of the individuals thai compose the social system. Instead, it is necessary to focus on the characteristics unique 1 0the higher order system itself as it interacts with its e n v i r o n ment. T h i s approach iscalledthe systems model o f h u m a n ecology.

THE SYSTEMSMODEL OF HUMAN ECOLOGY A major scientific development i n recent years has been the formulation o f "general systems theory," which is concerned with the general properties o f the structures and functions o f systems as such, rather than with their specificcontents. A c c o r d i n g to this iheoretical approach, atoms, cells, organisms, ecosystems, societies, and even the universe as a whole all share the c o m m o n propertics of being self-organizingsystems and can iherefore be studied in terms o f a c o m m o n theoretical perspective, Biological ecologists have long been aware of the systemic qualities o f the natural w o r l d , as their use o fthe t e r m ecosystem reveals. A m o n g social scientists, the recognition that h u m a n societies constitute organized systems is also an old one, dating back at least to the work of the French sociologist E m i l e D u r k h c i m . H i s writings, particularly The E l e m e n t a r y F o r m s of R e l i g i o u s Life (1915), provided ihe basis for the development of the structural-functional social systems model that has been the dominant parad i g m of British and A m e r i c a n anthropology and sociologysince the 1930s. Structural-functionalism, as first theoretically articulated by A . R . R a d cliffe-Brown (1965) and Bronislaw M a l i n o w s k i (1922), and as developed empirically by E . E . E v a n s - P r i t c h a r d (1940) and especially S i r R a y m o n d Firth (1936), saw allo f the diverse instiiuiions o f society as being organized into an integrated system, where each institution fits harmoniously with every other one, and where change in any single institution would ramify into complementary change i n all o f the other institutions with which it was functionally connected. T h e structural-functional model, with its conception o f societies as systems.

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proved to be o f great value operationally, producing many new insights into the ways in which societies were organized. N u m e r o u s formerly inexplicable customs suddenly became intelligible in the light of their functional relations with other institutions. T h e payment o f " b r i d e p r i c e " in tribal societies, for example, became comprehensible when ii was perceived that it served to strengthen marriage bonds by m a k i n g divorce more difficult and that such strengthening was important since marriages served politically to unite otherwise autonomous clans. T h u s , what had earlier been perceived as a quaint, "savage" custom was now recognized as serving important functions in the maintenance of tribal social solidarity. T h e ethnographic works o f the structural-functionalists give many more examples o f such functional relationships. To read E v a n s - P r i i c h a r d ' s monograph on the N u e r o f the S u d a n (J940) or R a y m o n d Firth's several works (1936) on the T i k o p i a n s o f Polynesia is to gain a strong conviction that these societies were integrated systems. C e r t a i n l y most Western social scientists became convinced o f this and thus the structural-functional model rapidly became the dominant theoretical perspective i n anthropology and sociology. Soon, however, criticisms began to be heard that the structural-functional model was a static one, unable to explain the occurrence o f change within the social system.* If, as the theory asserted, every institution was integrated perfectly with every other institution, what force could cause change to occur? T h e problem with the social system concept as developed by the structuralfunctionalists was not their postulation o f integration a m o n g system components but their failure to conceive o f the system as an open one. F o l l o w i n g the lead of D u r k h e i m (1938), it was argued that "social facts" must be explained only i n terms of other "social facts"; one could not seek the causes o f social change outside the boundaries of the social system itself. T h i s l i m i t a t i o no f the field of i n q u i r y — o r i g i n a l l y conceived as a way to prevent the resort to reductionist psychological o r physiological explanations of social systems such as " e x p l a i n i n g " the development of N a z i G e r m a n y in terms o f H i t l e r ' s pathological personality or " e x p l a i n i n g " the incest tabu i n terms o f man's instinctual h o r r o r of interbreeding—became an obstacle to understanding the process of systems change. T h e development of h u m a n ecology can be seen as an attempt to escape this theoretical impasse by treating social systems as open rather than closed systems. B e g i n n i n gwith J u l i a n Steward's concepi.of cultural ecology (1955, 1968), it was recognized that "social facts" might be explained not only i n terms of other "social facts" but also i n terms o f "ecological facts." *Acccptancc of the view that social institutions have a tendency toward integration need not imply acceptance of the view that social systems arc naturally homeosiaiic and stable. T h e Marxist conceptual model, lor example, certainly recognizes the role played by conflict in social evolution yet at the same lime holds that technology, social and political institutions, and ideology arc highly integrated phenomena at any particular stage ofeconomic growth.

Conceptual Approaches to H u m a n Ecology

Unfortunately, the new enthusiasm for e x p l a i n i n g social and cultural institutions in terms of environmental influences caused some analysts to lose sight of the systemic character o f society. Rather than seeking to understand how one open system (the social system) interacted with another open system (the ecosystem), they focused their attention on t r y i n g to explain how particular institutions (e.g., sacred cows, p i g feasts) might be explained i n relation to particular environmental conditions. T h a t this research strategy produced valuable insights is without question, but it could not lead to a comprehensive understanding o f society-environment interactions. A n alternative approach, the "systems model o f h u m a n ecology," describes social systems as they interact with ecologicalsystems. Adaptation is assumed to occur, not at the level o f discrete cultural traits or social institutions—as in the model of cultural ecology—or in terms of specific h u m a n populations—as in the ecosystem-based model o f h u m a n ecology—or in terms o f specific i n d i vidual decision makers—as in the actor-based model o f h u m a n ecology—but at the level o f the total social system as a system. C u l t u r a l trails, therefore, do not necessarily function to ensure the welfare o feither individualsor local populations but instead serve p r i m a r i l y to ensure the survival o f the social system itself. F r o m this perspective, the ritually regulated warfare of the T s e m b a g a is not seen as directly benefiting either most i n d i v i d u a l T s e m b a g a or the T s e m baga local population as a whole. In just one battle eighteen died and the people were defeated and driven from their territory, hardly what can be labeled an adaptive outcome either for the i n d i v i d u a l casualties or the dispossessed survivors. Instead, such endemic conflict is considered essential for m a i n taining the type o f social system characteristic o f the N e w G u i n e a highlands. Individuals, or even the whole T s e m b a g a local population could be destroyed, but the larger social system endured. In the systems model o f h u m a n ecology both the social system and the ecosystem with which it interacts retain their integrity as systems, with each c h a n g i n g its structural configuration according to its internal d y n a m i c s . A t the same time, however, it is recognized that each system receives energy, mater i a l , and information from the other, and these inputs also influence its structure a n d functioning. Each system, o f course, is also open to influence from other systems o f the same k i n d so that a social system may be altered by inputs received from a neighboring social system (the processes anthropologists call diffusion and acculturation) just as an ecosystem may be changed by inputs from other ecosystems (e.g., migration and colonization).C a u s a l i t y i n the systems model o f h u m a n ecology is thus extremely complex with no primacy being assigned a p r i o r i to any element or force in the total system. Figure 6 is a simplified d i a g r a m of the basic structural and functional relationships i n volved in the systems model of h u m a n ecology. T h i s model emphasizes four relational aspects:

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Conccplual Approaches to H u m a n Ei nlnijy

1. Inputs from the ecosystem into the social system—These inputs can be in the form of flows o f energy (e.g., food, petroleum), materials (e.g., protein, construction materials), or information (e.g., sounds, visual stimuli). 2. Inputs from the social system into the ecosystem—Again, these can take the form o f flows o f energy, materials, or information generated by human activities. 3. C h a n g e i n the institutions m a k i n g up the social system in response to inputs from the ecosystem—Such change may be either primary, as when an increase in the death rate due to environmentally transmitted diseases changes the population structure o fa society, or secondary, as other social system institutions change in response to environmentally generated primary change i n one institution. Social system changes i n response to inputs from the ecosystem may be and often are adaptive, that is, they contribute to the c o n t i n u i n g survival o f the social system under changed e n v i r o n m e n t a l conditions. T h e y need not, however, result in a better or happier way o f life for individual h u m a n participants. In other words, it is the social system itself, rather than the people who are involved i n it, that is the unit o fnatural selection and adaptation.

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4. C h a n g e s i n the ecosystem in response to inputs from the social system— Just as h u m a n society changes i n response to environmental influences, so docs the ecosystem change in response to h u m a n influences. S u c h change m a y be either primary, the direct impact o f a h u m a n activity o n an ecosystem component such as the k i l l i n g offo fa particular a n i m a l species by o v c r h u n t i n g , or secondary, alterations in other ecosystem components caused by anthropogenic p r i m a r y change i n one component.

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