Conceptual Approaches to Human Ecology

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ISSN-0739-6716

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

Conceptual Approaches to Human Ecology

by A. Terry Rambo

East-West Center

Honolulu, Hawaii

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T H E EAST-WEST CENTER is an educational institution established in Hawaii in 1960 by the United States Congress. The Center's mandate is "to promote better relations and understanding among the nations of Asia, the Pacific, and the United States through cooperative study, training, and research."

Each year nearly 2,000 graduate students, scholars, professionals in business and government, and visiting specialists engage in research with the Center's international staff o n major issues and problems facing the Asian and Pacific region. Since

1960, more than 30,000 men and w o m e n from the region have participated in the Center's cooperative programs.

The Center's research and educational activities are conducted in five institutes- Communication, Culture Learning, Environment and Policy, Population, and Re- source Systems—and in its Pacific \s\ands Development Program, O p e n Grants, and Center-wide programs.

Although principal funding continues to c o m e from the U.S. Congress, more than 20 Asian and Pacific governments, as well as private agencies and corporations, have provided contributions for program support. The East-West Center is a public, nonprofit corporation with an international board of governors.

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 1977 to increase understanding of the interrelationships a m o n g policies designed to meet a broad range of human and societal needs overtime and the natural systems and resources o n which these policies depend or impact. Through interdisciplinary and multinational programs of research, study, and training, the Institute seeks to develop and apply concepts and approaches useful in identifying alternatives available to decision makers and in assessing the implications of such choices. Progress and results of Institute programs are disseminated in the 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 Policy Institute

East-West Center 1777 East-West Road Honolulu, Hawaii 96848

Conceptual Approaches to Human Ecology

by A . Terry Rambo

RESEARCH INFORMATION SERVICES EAST-WEST CENTER

MAY - 51999

1601 EAST-WEST H0A0 HONOLULU, HAWAII 96848-1601

Research Report No. 14 • June 1983 East-West Environment and Policy Institute

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A . T E R R Y R A M B O is a research associate and c o o r d i n a t o r of the H u m a n Interactions with T r o p i c a l 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 P o l i c y Institute, E a s i - W e s i 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 v i s i t i n g professor ai the Dalat U n i v e r s i t y G r a d u a t e School of Politics and Eco- nomics in S a i g o n , V i e t n a m .

Library of Congress Cataloging in Publication Data

Rambo. A. Terry

Conceptual approaches to human ecology.

(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

Printed in the United Slates of America.

CONTENTS

A C K N O W L E D G M E N T S v

A B S T R A C T¹

I N T R O D U C T I O N 1 T H E O R I G I N S O F H U M A N E C O L O G Y 2

E N V I R O N M E N T A L D E T E R M I N I S M 3 E N V I R O N M E N T A L P O S S I B I L I S M 4 T H E C O N C E P T O F C U L T U R A L E C O L O G Y 6

T H E E C O S Y S T E M - B A S E D M O D E L O F H U M A N E C O L O G Y 13 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 E C O L O G Y 18 T H E S Y S T E M S M O D E L O F H U M A N E C O L O G Y 23

C O N C L U S I O N 29 B I B L I O G R A P H I C N O T E 31

R E F E R E N C E S 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-of J a v a and the O u t e r

Islands of Indonesia 9

Figures

Figure 1. T h e model o f e n v i r o n m e n t a l d e t e r m i n i s m 4 F i g u r e 2. T h e model of e n v i r o n m e n t a l possibilism 5

F i g u r e 3. T h e model o f c u l t u r a l ecology ? Figure 4. T h e ecosystem-based model of h u m a n ecology 14

F i g u r e 5. T h e actor-based model o f h u m a n ecology 19 Figure 6. Social system-ecosystem interactions 26

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ACKNOWLEDGMENTS

T h i s research report is a revised a n d expanded version o f m y paper, " T h e D e v e l o p m e n t o f a C o n c e p t u a l F r a m e w o r k 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 D e p a r t m e n t o f A n t h r o p o l o g y a n d 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 w h i l e I was a v i s i t i n g research fellow at the East-West E n v i r o n - ment a n d 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 w i t h several E A P I staff members a n d 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, L a w r e n c e S. H a m i l t o n , a n d A n d r e w P.

V a y d a , greatly helped m e to clarify m y 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 , a n d Percy E . Sajise led me to make further revisions i n this presentation.

T h e field research that p r o v i d e d 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 a n d 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 chan- cellor for research at the U n i v e r s i t y o f M a l a y a , is gratefully acknowledged.

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 . W o l f , 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 w i t h A l i c e G . Dewey, K a r l L . Hutterer, Jeff R o m m , a n d 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 m a y e x h i b i t .

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Conceptual Approaches li> Homait KcoJoiry )

Conceptual Approaches to Human Ecology

by A . Terry Rambo

ABSTRACT

A n u m b e r o f very different conceptual approaches have been e m p l o y e d i n h u m a n ecology. T h i s report reviews several o f the most important analytic frameworks: e n v i r o n m e n t a l d e t e r m i n i s m a n d p o s s i b i l i s m , cultural ecology, the ecosystem-based m o d e l , a n d the actor-based m o d e l . 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 a n d weaknesses are assessed. F i n a l - ly, an alternative conceptual approach—the systems model o f h u m a n ecol- o g y — i s proposed. In this interactive m o d e l , the h u m a n social system is seen as b e i n g linked to its ecosystem through the interchange o f energy, materials, a n d i n f o r m a t i o n .

INTRODUCTION

H u m a n ecology, most broadly defined as the study o f h u m a n interactions w i t h the e n v i r o n m e n t , 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 g several different theoretical approaches in u n d e r s t a n d i n g h u m a n - e n v i r o n m e n t interactions.

W h / i e such diversity o f viewpoints w i t h i n a scientific d i s c i p l i n e m a y indicate youthful vigor, it also can present the nonspccialist with severe obstacles to g a i n i n g an u n d e r s t a n d i n g 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 p o l e m i c character o f p r o g r a m m a t i c 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 f they are d e a l i n g w i t h theology, advo- c a t i n g their o w n models as the only true a n d correct ones while d i s m i s s i n g 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 o n 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 w i t h the e n v i r o n m e n t are described in the historical order i n w h i c h they have appeared in the scientific literature. S u c h a chronological approach helps to illustrate the interplay between research results a n d the f o r m u l a t i o n o f new theoretical c o n - cepts. N o superiority is i m p u t e d to more recently developed paradigms. In fact, certain currently popular models may be viewed as regressive from the standpoint o f the development of social science theory as a whole.

A l t h o u g h largely discredited a m o n g social scientists, classical a n d early m o d e r n theories o f e n v i r o n m e n t a l influence on h u m a n affairs ( d e t e r m i n i s m a n d 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 m o d e l of c u l t u r a l 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 m o d e l first proposed by A n d r e w P. V a y d a a n d R o y A . R a p p a p o r t .

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, a n d the systems model o f h u m a n ecology stresses investigation o f interactions between h u m a n social systems a n d ecosystems based on their reciprocal exchange o f energy, materials, a n d i n f o r m a t i o n .

THE ORIGINS OF HUMAN ECOLOGY

Since ancient l i m e s there have been m a n y attempts to e x p l a i n events i n terms o f e n v i r o n m e n t a l influences o n h u m a n behavior. A s t r o l o g y represents one early system o f thought relating e n v i r o n m e n t a l forces to h u m a n actions.

A l t h o u g h wholly discredited as a scientific theory by m o d e r n astronomy, the belief that the m o v e m e n t o f the stars controls h u m a n destiny retains a strong hold o n the p o p u l a r i m a g i n a t i o n , as evidenced by the appearance o f astrologi- cal advice c o l u m n s i n m a n y daily newspapers.

In a v e i n m o r e compatible w i t h 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 a n d a force for change i n the e n v i r o n m e n t . It was suggested, for example, that the different forms o f political o r g a n i z a t i o n o f the G r e e k city states a n d the East- ern empires reflected the influences o f climate o n the personalities o f their citi-

ConccpiuaJ Approaches w Human Ecology 3

zens. T h i s theme later was developed by M o n t e s q u i e u and other F r e n c h writers o f the E n l i g h t e n m e n t and advocated i n recent times by the A m e r i c a n geographer S a m u e l H u n t i n g t o n . O t h e r classical writers c o m m e n t e d o n the destruction o f the natural landscape of A t t i c a a n d N o r t h A f r i c a resulting from deforestation a n d o v e r g r a z i n g , a theme taken up i n the mid-1800s by G e o r g e 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 ecological catastrophe w r i t i n g s so p o p u l a r recently. These early w r i t i n g s , however, were generally anecdotal rather than presenting a coherent theory o f h u m a n - e n v i r o n m e n t relationships. It was o n l y w i t h the development o f geography a n d anthropology as scientific disciplines in the latter part of the nineteenth century that h u m a n ecology became the subject of systematic study. T h e first theoretical approach to be tried, however, was that of e n v i r o n m e n t a l 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 t u r n o f the century, geographers, notably F r i e d r i c h R a t z e l i n G e r m a n y a n d his A m e r i c a n disciple, E l l e n C . S e m p l e , 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 e n v i r o n m e n t a l d e t e r m i n i s m . Followers o f this school, w h i c h d o m i - nated geographical thought well into the 1920s, asserted that all aspects o f h u m a n culture a n d behavior were caused directly by e n v i r o n m e n t a l influences ( F i g u r e 1). F o r e x a m p l e , the B r i t i s h were a n a t i o n 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 m i n d s toward a single G o d ; the E s k i m o s were p r i m i t i v e nomads because the harsh conditions o f their arctic habitat forbade their development into a c o m p l e x c i v i l i z a t i o n . T h e books o f Semple a n d others were filled w i t h endless listings o f seemingly p l a u - sible e n v i r o n m e n t a l determinants o f c u l t u r a l forms.

A l t h o u g h seductive when first encountered, such c l a i m s o f causal correla- tion between e n v i r o n m e n t a n d culture were easily refuted once g i v e n careful consideration. F o r e x a m p l e , the T a s m a n i a n s , w h o lived o n 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; a n d the icy wastes once traversed by E s k i m o d o g sleds are now the scene o f s n o w m o b i l e races alongside giant o i l pipelines. T h e r e is s i m p l y too m u c h v a r i a t i o n in h u m a n behavior i n seemingly s i m i l a r geographical settings for it t o be e n v i - r o n m e n t a l l y d e t e r m i n e d .

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0 ^

CULTURAL FORM

o"1

Figure 1. T h e 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 e n v i r o n m e n t a l possibilism, was proposed. Its proponents asserted that while the e n v i r o n m e n t did not directly cause specific c u l t u r a l developments, the presence o r absence of specific e n v i r o n m e n t a l factors placed l i m i t s o n such developments by either p e r m i t t i n g or f o r b i d d i n g their occurrence ( F i g u r e 2). T h u s , island peoples c o u l d be seafarers, but residents o f Inner M o n g o l i a c o u l d not be; inhabitants of temperate regions m i g h t practice a g r i c u l t u r e , but those l i v i n g in arctic lati- tudes c o u l d not. T h e value o f the possibilist approach was perhaps best dem- onstrated by the A m e r i c a n anthropologist A . L . K r o e b e r , who showed that the Indians o f northwestern N o r t h A m e r i c a c o u l d 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 m o n t h s r e q u i r e d for the maize plants to reach maturity. T h e i r e n v i r o n m e n t thus l i m i t e d the ability o f their culture to evolve in an a g r i c u l t u r a l d i r e c t i o n .

A possibilist stance was also taken by the B r i t i s h 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 w h i c h he argued that the development of c i v i l i z a t i o n s c o u l d 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 b e n i g n tropics failed to evolve because they were not sufficiently challenged by their e n v i r o n m e n t ;

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CULTURAL

TRAITS

M E N T A L S C R E E N

Figure 2. The model of environmental possibilism.

those in extremely harsh habitats such as the E s k i m o s i n the arctic remained forever p r i m i t i v e because s i m p l y c o p i n g with the demands of their e n v i r o n - ment sapped all o f their creative energies. O n l y those cultures in e n v i r o n m e n t s offering sufficient but not excessive challenges had the possibility of progress- ing to higher stages of c i v i l i z a t i o n .

P o s s i b i l i s m suffers from one o v e r r i d i n g defect as a scientific theory; it lacks any general predictive o r explanatory power since it is able to e x p l a i n o n l y why certain developments could not occur i n certain environments. It is totally unable to predict whether o r not they w o u l d o c c u r under favorable circumstances. F o r example, the failure o f Eskimos to grow corn is e x p l a i n a b l e , but possibilism cannot e x p l a i n why the E n g l i s h were great seafarers while the T a s m a n i a n s were not. C l e a r l y , the difference in the latter case was due to existence o f very different c u l t u r a l traditions and bodies o f technological k n o w l - edge rather than reflecting e n v i r o n m e n t a l influences. In short, as the British anthropologist D a r y l l F o r d e concluded i n his book, H a b i t a t , Economy a n d Society (1934), w h i c h was perhaps the last major scientific exploration o f p o s s i b i l i s m ,

"between the physical e n v i r o n m e n t and h u m a n activity there is always a m i d - dle t e r m , a collection o f specific objectives a n d values, a body o f knowledge a n d belief: i n other words, a c u l t u r a l pattern."

W i t h this r e a l i z a t i o n , social scientists tended to turn from s t u d y i n g h u m a n interactions w i t h the e n v i r o n m e n t , preferring instead to focus o n the seemingly more profitable study o f the internal structure a n d functioning o f c u l t u r a l a n d social systems. F o l l o w i n g the F r e n c h 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 " s o c i a l facts" could be explained o n l y i n terms of other social

facts, c u l t u r a l development was explained by the concept o f diffusionism—the

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historical spread o f traits from one culture to others, without reference b e i n g made to possible e n v i r o n m e n t a l influences o n the process. It was not u n t i l the

1950s that social scientists, acting u n d e r the influences o f J u l i a n Steward's concept o f c u l t u r a l ecology, again t u r n e d 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 .

THE CONCEPT OF CULTURAL ECOLOGY

A l t h o u g h his first papers o n 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 c u l t u r a l 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 h a d 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 c u l t u r e . D r a w i n g on the theoretical methods that biological ecologists were then devel- o p i n g to study the adaptation o f a n i m a l species, i n p a r t i c u l a r relating specific organs to specific features o f the e n v i r o n m e n t , Steward attempted to e x p l a i n certain structural aspects o f Shoshone culture i n terms o f the resources available i n the i m p o v e r i s h e d semi desert habitat. In what is still one of the finest ethnographies ever p u b l i s h e d , S t e w a r d (1938) made a c o n v i n c i n g case that the low density o f the Shoshone p o p u l a t i o n , its o r g a n i z a t i o n into small family bands w i t h highly dispersed and flexible residence patterns a n d lack o f territo- riality, a n d the lack o f powerful permanent leaders all reflected the inability o f Shoshone technology to extract a large a n d stable supply of food from the t h i n l y scattered a n d sporadically available resources o f the a r i d e n v i r o n m e n t .

It was Steward's v i e w that not all aspects of Shoshone culture could be e x p l a i n e d i n ecological t e r m s — m a n y traits were present as simply the accidental result o f diffusion from n e i g h b o r i n g tribes—but that o n l y some elements, w h i c h he labeled as "the cultural core," had adaptive significance. In particular, he thought technology, economics, p o p u l a t i o n , a n d social o r g a n i z a t i o n were likely to be part o f the core, although he insisted that it was necessary to demonstrate this e m p i r i c a l l y in each case. H e tended to give special emphasis to the relationship between technology a n d the e n v i r o n m e n t i n his m o d e l o f c u l t u r a l ecology ( F i g u r e 3). *

*lt is interesting to note that E. E. Evans-Prifchard, • leading British social anthropologist, sug- gested a similar ecological approach at almost the same time as Steward although neither man appears to have been influenced by the other's work. Pritchard (19+0) related the' settlement pat- tern of the Nucr pastorialisis of the Sudan to seasonal changes in resource availability. Despite the acclaim that his monograph met from his colleagues, Pritchard's ecological approach was not emulated by them and British social anthropologists were not to become involved again in human ecology research until much later than the Americans.

Conceptual Approaches to Human Ecology

TRAIT D I F F U S I O N

F R O M O T H E R S O C I E T I E S

M i l

I * Co

L A N G U A G E A R T

V A L U E S R E L I G I O N

SOCIOPOLITICAL SYSTEM

P O P U L A T I O N E C O N O M I C

P A T T E R N S ORGANIZATION

E X P L O I T A T I V E TECHNOLOGY

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E C O L O G I C A L I N F L U E N C E S

Figure 3. T h e model of cultural ecology.

T h e A m e r i c a n anthropologist C l i f f o r d 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 g the great d e m o g r a p h i c disparity that exists between J a v a a n d 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 , w i t h an average density o f 480 persons per square kilometer ( k m¹) but w i t h more than 2,000 p e r s o n s / k m² 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 per- s o n s / k m ' . G e e r t z has suggested that these various p o p u l a t i o n densities reflect

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the differing a g r i c u l t u r a l adaptations e m p l o y e d i n the two regions, which i n t u r n relate to their differing e n v i r o n m e n t s (Table I).

T h e topography of J a v a is one o f relatively y o u n g v o l c a n i c mountains sur- r o u n d e d 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 a n d irregular, offering few opportunities for development of large, gravity fed i r r i g a t i o n 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 , o n the other hand, the rivers are short a n d 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 soils o f the volcanic slopes d o w n into the paddy fields.

In conformity w i t h these e n v i r o n m e n t a l factors, J a v a is p r e d o m i n a n t l y a region o f s a w a h irrigated wet rice agriculture while l a d a n g shifting c u l t i v a t i o n is the p r i n c i p a l technology e m p l o y e d i n the outer islands. L a d a n g , o r " 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 l a n d in the forest, allows the vegetation to d r y a n d then b u r n s it before p l a n t i n g a crop. After one or, at most, two harvests, fertility is exhausted a n d the plot is abandoned a n d a new field is cleared in the forest.

T h e a b a n d o n e d plot is gradually rcoccupied by forest vegetation, a n d after ten to fifty years it may again be cleared a n d farmed. S w i d d e n i n g represents an effective adaptation to f a r m i n g the i m p o v e r i s h e d soils o f tropical r a i n forest areas where most o f the available nutrients are stored i n the vegetation, It gives high yields w i t h relatively low h u m a n labor inputs since most of the work is done by the fire, w h i c h simultaneously clears the field, releases the stored nutrients back to the soil i n the f o r m o f ashes where they are readily available to the g r o w i n g crops, a n d kills off pests a n d weed seeds that w o u l d compete w i t h the crops. T h e major l i m i t a t i o n o f swidden agriculture is that a large q u a n t i t y o f l a n d is r e q u i r e d to support each farmer. A n i n d i v i d u a l farmer requires not o n l y the plot currently under c u l t i v a t i o n but also a reserve o f forest l a n d adequate for the needs o f c u l t i v a t i o n u n t i l the o l d plots are again ready for c l e a r i n g . 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 m³. If population should increase, it is necessary to shorten the forest fallow cycle, c a u s i n g r a p i d destruction o f the productive capability o f the l a n d due to erosion a n d nutrient loss.

In contrast to the i m p e r m a n e n c e a n d instability o f the l a d a n g systems, sawah agriculture is noted for its stability a n d 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 q u a l i t y o f soil that is the most important factor i n grow- ing wet rice. M o r e o v e r , the y i e l d is strongly influenced by the amount of h u m a n labor put into w o r k i n g the c r o p — t r a n s p l a n t i n g rather than s o w i n g the seed by broadcasting, more careful a n d frequent weeding, a n d c l e a n i n g a n d maintenance o f i r r i g a t i o n channels all contribute to a higher yield o f rice per

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10 Environment and I'olicy Institute

hectare. S u c h a system may encourage population increase, since the more c h i l d r e n (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 c o n d i t i o n s , may contribute to the d e m o g r a p h i c disparities between J a v a a n d 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 u n d e r s t a n d i n g of how traditional societies arc effectively adapted to their environments, l i s successes have been achieved p r i m a r i l y in studying small-scale, p r i m i t i v e societies, however, especially those where a stable relationship has been established between a static population a n d an u n c h a n g i n g e n v i r o n m e n t . T h e concept has been m u c h less applicable to complex m o d e r n societies where the actions o f large h u m a n populations are p r o d u c i n g r a p i d e n v i r o n m e n t a l change with consequent need for rcadaptation o f the cultural core. A s conceived by S t e w a r d a n d used by others, the c u l t u r a l ecology model lacks any systematic conceptualization of the e n v i r o n m e n t or o f the ways in which h u - m a n activities i m p i n g e o n it. T h u s , its emphasis is almost exclusively o n the h u m a n side of the h u m a n - e n v i r o n m e n t equation, focusing o n the adaptation of culture to nature while i g n o r i n g e n v i r o n m e n t a l change i n response to h u - m a n i n t e r v e n t i o n .

T h i s fundamental weakness o f the concept of c u l t u r a l 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 deter- m 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 e n v i r o n m e n t is the prime mover o f c u l t u r a l e v o l u t i o n , H a r - ris asserts that the forms taken by all other aspects of culture are determined by the relationship between technology a n d the e n v i r o n m e n t . 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, c o n t r a r y to the accepted v i e w t h a t H i n d u s keep excessive n u m b e r s 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, h e l p i n g 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 t e c h n o - c n v i r o n m e n t a l factors.

A c c o r d i n g to the c o n v e n t i o n a l v i e w , between o n e - t h i r d a n d one-half o f the 80 m i l l i o n cows i n India should be e l i m i n a t e d as e c o n o m i c a l l y wasteful a n i - mals. Because they arc so badly n o u r i s h e d , 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 a n d interfering with traffic. In some areas cattle actually compete with h u m a n s for food, being kept i n special b o v i n e 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 b e i n g slaughtered. H e n c e , it is c o m m o n l y said that this is an example of

Conceptual Approaches to Human Ecology

religious ideology interfering w i t h 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 I n d i a n cattle have overlooked numerous benefits thai the seemingly excess animals provide to the peasant p o p u l a t i o n . 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 I n d i a n farms. It is only by h a v i n g large numbers of cows that the d e m a n d of the farmers for bullocks can be met. S e c o n d , cows yield a steady supply of d u n g , a n d cow d u n g is the m a i n source of fuel for domestic c o o k i n g 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 o f d u n g b u r n e d each year i n India is equal to 35 m i l l i o n tons of c o a l . M u c h o f the rest of the d u n g is used as m a n u r e in the fields. T h e hides salvaged from deceased cows also provide the basis o f a large leather industry, w h i c h provides a livelihood for m a n y lower-casle families.

Not o n l y does H a r r i s show that the cows provide m a n y valuable e c o n o m i c benefits to the I n d i a n peasants, he also argues that they d o so at m i n i m a l cost to the h u m a n p o p u l a t i o n . H e claims that cows rarely compete directly with people for food since they are not fed g r a i n or fodder g r o w n on l a n d that c o u l d 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 c o u n - tries. Instead, the cattle w a n d e r g r a z i n g freely o n whatever grass they can find g r o w i n g beside roads, a r o u n d telephone poles, a n d between the ties o n rail- road tracks. T h e y also arc allowed to graze o n the stubble left i n grain fields after the harvest. In other words, the cows capture otherwise u n u t i l i z e d energy a n d 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 , a n d 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 o n k i l l i n g cattle exists as an expression of the ecological value o f cattle to the I n d i a n h u m a n p o p u l a t i o n .

H a r r i s ' paper has been subject to severe criticism o n e m p i r i c a l a n d theoretical g r o u n d s . 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 c l a i m e d that 5 percent of the arable l a n d in I n d i a is i n fact used as pasture a n d for g r o w i n g fodder to feed cattle, so these a n i m a l s do i n fact compete directly w i t h h u m a n s 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 o n k i l l i n g a n d con- s 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 e x a m p l e , 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 p r o h i b i t i o n o n 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 o n a life of their o w n a n d can be diffused into new e n v i - ronments where they m a y appear less rational ecologically. T h u s , M u s l i m s in Indonesia a n d M a l a y s i a are forbidden by their religion from eating pork although the p i g is ecologically p r o b a b l y 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 l i m i t e d to those areas close to the coast where sufficient supplies offish are available to p r o v i d e a substitute for pork. Populations o n the interior side of what has been called the " p i g l i n e " n u t r i t i o n a l l y cannot 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 o n the benefits that i n d i v i d u a l I n d i a n farmers derive from h a v i n g large numbers o f cows, he wholly ignores the destructive impact these animals have o n the e n v i r o n m e n t a n d 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, a n d the barren soil of the hill slopes has had its structure destroyed by the impact of the cow's hooves a n d is h i g h l y subject to erosion d u r i n g the brief but intense monsoon rains.

T h e rainwater, w h i c h was formerly trapped by tree roots a n d grasses a n d then gradually released p r o v i d i n g i r r i g a t i o n water to farms o n the plains below d u r - i 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 a n d causing greai floods in the lowlands. T h a i the e n v i r o n m e n t a l 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 p r o g r a m 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 c r o p l a n d 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 l i m i t a t i o n s o f the concept o f c u l t u r a l ecology indicates, research o n h u m a n - e n v i r o n m e n t relations needs a conceptual framework that pays adequate attention to the possibility of e n v i r o n m e n t a l 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 a n d then m a i n t a i n e d u n c h a n g i n g ever after- w a r d . Instead, the relationship between h u m a n s a n d nature is a d y n a m i c one i n w h i c h both culture a n d the e n v i r o n m e n t continue to adapt a n d 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 e n v i r o n m e n t a l side o f the relationship that Jed to f o r m u l a t i o n o f the ecosystem-based model o f h u m a n ecology.

Conceptual Approaches to H u m a n Ecology

THE ECOSYSTEM-BASED MODEL OF HUMAN ECOLOGY

B a s i n g their approach o n the concept o f the ecological system 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 V a y d a a n d R o y R a p p a p o r t suggested that instead o f study- i 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 v i e w , h u m a n beings constitute s i m p l y another population a m o n g the m a n y populations o f plant a n d a n i m a l 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 ( F i g u r e 4). C u l - tural traits arc of interest o n l y as they can be shown to contribute to the population's s u r v i v a l in the context o f the ecosystem.

S u c h a framework, however attractive it might seem for reintegrating hu- m a n ecology into general ecological t h i n k i n g , serves to stand anthropology o n its head by e m p h a s i z i n g the biological survival of populations rather than the persistence of the sociocultural systems in which these populations partici- pale. C u l t u r a l traits arc studied in terms of the possible c o n t r i b u t i o n 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 g u i d e d by the unspoken assumption that i f a c u l t u r a l trait exists then it must somehow necessarily serve the adaptive needs of a local p o p u l a t i o n .

T h e ecosystem-based model of h u m a n ecology is exemplified by R o y R a p - paport's w e l l - k n o w n 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 g r o u p 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 w i t h the available resources o f their e n v i r o n m e n t . R e l i g i o n , an institution that S t e w a r d h a d 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 p l a y i n g 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 e m p l o y a swidden system o f f a r m i n g s i m i l a r 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 p i g . A c o n t i n u i n g puzzle to anthropologists has been their custom o f slaughtering a n i m a l s only o n ritual occasions, w h e n hundreds o f pigs m a y 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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14 Environment and I'olicv Institute

NEIGHBORING HUMAN POPULATIONS

'REGIONAL- INTERACTIONS:

TRADE, MARRIAGE.

WARFARE. ETC

HUMAN POPULATION

ABIOTIC FACTORS (SOIL, AIR, WATER)

PLANT AND ANIMAL POPULATIONS

Figure 4. The ecosystem-based model of human ecology.

people go meatless for most of the rest o f the t i m e . F r o m a n u t r i t i o n a l standpoint, it w o u l d seem better to slaughter smaller n u m b e r s o f animals o n 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 popu- l a t i o n . T h e great r i t u a l feasts have therefore often been thought to be an example of a maladaptive cultural trait s i m i l a r to the sacred cows of I n d i a .

After spending fourteen months l i v i n g a m o n g the T s e m b a g a , R a p p a p o r t concluded that, far from being a maladaptive feature o f their culture, the ritual regulation o f p i g 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 15

strictiun o f k i l l i n g pigs only o n certain ceremonial occasions serves to (1) max- i m i z e the supply o f protein at times when the T s e m b a g a most need it, a n d (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 o f carbohydrates i n the form of sweet potatoes, t a i o , a n d sugar cane in their swidden plots, but they are c h r o n i c a l l y short o f protein, particularly high qual- ity 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 l i m i t e d n u m b e r 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, a n d the b e g i n n i n g a n d e n d 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, a n d fear all place the h u m a n o r g a n i s m under greai- cr than usual stress with consequent greater physiological d e m a n d for protein, the basic b u i l d i n g block for bodily tissues. I n d i v i d u a l s c o n s u m i n g an inade- quate quantity o f protein arc unable lo produce sufficient antibodies to recover q u i c k l y from stress effects a n d 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 . E v e n a temporary increase i n protein intake can produce d r a m a t i c recoveries a m o n g such m a l n o u r i s h e d invalids. T h u s , even though the T s e m b a g a k i l l i n g of pigs is done for supernatural reasons to appease evil spirits believed to cause sickness a n d ensure the help o f ancestral spirits in fighting, since it occurs at times o f illness and war it may allow the h u m a n 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 f p r o d u c i n g .

R a p p a p o r i not only sees ritual as s e r v i n g the n u t r i t i o n a l best interests o f the T s e m b a g a population; he further claims the ritual cycle functions to m a i n t a i n the population ai a density compatible w i t h the long-term c a r r y i n g capacity o f the ecosystem by regulating die frequency a n d intensity with which warfare occurs. A c c o r d i n g to the c u l t u r a l g r o u n d 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 l i m i t e d periods, the beginnings a n d ends o f which are signaled by great ritual p i g feasts. N o g r o u p can go to war, however great the p r o v o c a t i o n , u n t i l 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, a n d their ability to raise pigs is d e t e r m i n e d by the o v e r a l l state o f their ecosystem.

Warfare o f the sort practiced i n h i g h l a n d N e w G u i n e a until quite recently, while often more o f a r i t u a l than a real battle, was o n occasion quite a bloody affair w i t h participating groups suffering heavy c a s u a l t i e s . W h e n their losses became unacceptable, the c o n t e n d i n g 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 m e n from n e i g h b o r i n g villages who h a d served as their allies d 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 r i t u a l l y 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-concluded - r o u n d of fighting a n d therefore they c o u l d not rely o n their help again should new fighting b e g i n . It was only after they held a second, larger festival involv- ing the slaughter o f hundreds of pigs that their debt w o u l d be considered p a i d and the ancestral spirits again thought w i l l i n g to help them. A t that point warfare w o u l d 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 r e b u i l d their herd to sufficient size to hold the second feast. D u r i n g those years the h u m a n p o p u l a t i o n also had time to r e b u i l d , m a k i n g up for the losses in w a r r i o r s it h a d suffered d u r i n g the previous fighting. O n l y when both the p i g population a n d 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 p i g h e r d , 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 w i t h the l i m i t e d c a r r y i n g capacity 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 w h i c h 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 a n d theoretical, about the validity of his analysis. M a r g a r e t M c A r t h u r (1974), a l e a d i n g A u s t r a l i a n n u t r i t i o n a l anthropologist, has s h o w n , for e x a m p l e , that the T s e m b a g a are the best nourished o f any h i g h l a n d N e w G u i n e a population yet studied, w i t h a n 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 o r injury is apparently unfounded. E v e n i f T s e m b a g a invalids w o u l d benefit from a greater intake o f protein, R a p p a p o r t presents no h a r d evidence that they i n fact receive it from the pigs killed at the c u r i n g rituals, a c c o r d i n g to M c A r t h u r . A s she notes, the fact that the sick person receives o n l y the'liver as his share o f the meat does not suggest ingestion o f any very great quantity o f p r o t e i n .

T h e k i l l i n g o f large numbers o f pigs o n festival occasions is also shown by M c A r t h u r to be an extremely inefficient way o f using the l i m i t e d 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 o n pork, c o n s u m i n g as m u c h as a k i l o g r a m o 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 of about 50 grams, the bulk of this intake at festival times is n u t r i t i o n a l l y wasted, being s i m p l y b u r n e d as extra calories. C o n t r a r y to R a p p a p o r t ' 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 17

quent intervals w o u l d be more efficient from a n u t r i t i o n a l standpoint. S u c h ' regular slaughter w o u l d also have greater ecological efficiency since it w o u l d remove pigs from the herd as soon as they reached m a t u r i t y a n d ceased to be efficient converters of vegetable food to p r o t e i n . T h e n the people w o u l d not have to support them for m a n y extra u n p r o d u c t i v e years while w a i t i n g for a large enough h e r d to be assembled to hold the r i t u a l feast. F a r from m a x i m i z - ing the flow o f energy a n d nutrients from the ecosystem to the h u m a n popula- t i o n , the ritual regulation o f T s e m b a g a p i g h u s b a n d r y thus appears to be highly wasteful and inefficient.

O f course the T s e m b a g a are not concerned w i t h ecological efficiency; they slaughter pigs for religious a n d social reasons a n d not because they are s t r i v i n g 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 d i s p l a y the wealth a n d power o f the tribe to potential friends a n d enemies alike while e n s u r i n g the support o f both their ancestoral spirits a n d 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 o n these occasions, however wasteful it m a y 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 R a p p a p o r t has done i n terms of the interaction o f the T s e m b a g a population w i t h their local ecosystem, but-in terms of the adaptation o f the tribal society to the conflict-ridden social e n v i r o n m e n t o f the N e w G u i n e a highlands.

F r o m the latter perspective, it is particularly i r o n i c 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 e n v i r o n m e n t , h a v i n g been defeated i n battle i n 1953, d r i v e n off their ancestral lands, and forced to take

refuge a m o n g their allies. A s R a p p a p o r t h i m s e l f reports, "the T s e m b a g a ceased to exist as a g r o u p after their defeat, a n d , i f it were not for the agents of the newly a r r i v e d A u s t r a l i a n government who offered to protect t h e m , it is u n l i k e l y that they w o u l d as a g r o u p have returned to their t e r r i t o r y " (1968).

S u c h a g r o u p hardly seems an appropriate choice to illustrate a theory of the role that r i t u a l 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 a n d 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 a n d the regional ecosystem, not between transitory local populations like the T s e m b a g a a n d the small territories they exploit directly.

Despite the m a n y serious criticisms o f R a p p a p o r t ' s study, it remains a v a l u - able c o n t r i b u t i o n to h u m a n ecology. Perhaps its greatest impact has been to focus attention o n the adaptive significance o r ideology, an aspect of culture that Steward h a d largely excluded from consideration as affecting h u m a n interactions with the e n v i r o n m e n t . B y suggesting plausible ways in w h i c h religious r i t u a l might regulate T s e m b a g a relations w i t h other components of their ecosystem R a p p a p o r t opened the eyes of social scientists concerned w i t h ccol-

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18 Environment ami Polity Institute

ogy to a new area o f study. T h a t his particular model o f the interactions between r i t u a l , h u m a n p o p u l a t i o n , a n d other ecosystem components may not be a v a l i d one is a reflection o n the specific conceptual approach that he e m p l o y e d , not a rejection of his more fundamental insight that religious ritual c o u l d be just as significant ecologically as the technological aspects o f culture that Steward emphasized.

T h e professional debates that followed publication o f R a p p a p o r t ' s book also have focused attention o n 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 e n v i r o n m e n t . 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 a n d focusing o n a local p o p u - lation 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 c o n v i c t i o n that what has been called the actor-based model of h u m a n ecology has been formulated.

THE ACTOR-BASED MODEL OF HUMAN ECOLOGY

In the face of severe e m p i r i c a l problems in defining the social unit of ecological adaptation, it has been suggested that adaptation occurs at the level of i n d i v i d u a l s rather than of cultures o r 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 c o n - cern w i t h 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 a n d e v o l u t i o n a r y biologists' current preoccupation w i t h s h o w i n g that natural selection operates exclusively at the level o f the i n d i v i d u a l o r g a n i s m . F r o m this perspective, any higher levels o f o r g a n i z a t i o n , 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 m a n y i n d i - v i d u a l organisms.

In the case of h u m a n society, therefore, e n v i r o n m e n t a l adaptation is seen as o c c u r r i n g not as the result o f natural selection o n the c u l t u r a l o r 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 e n v i r o n m e n t . I n d i v i d u a l s are as- sumed to be m a k i n g choices constantly about how to exploit available resources w h i l e c o p i n g with e n v i r o n m e n t a l hazards. T h o s e who make the

" c o r r e c t " choices w i l l survive a n d prosper; those who choose less wisely will be selected against. O v e r t i m e , the more successful adaptive strategics w i l l become institutionalized as c u l t u r a l 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).

Conceptual Approaches to H u m a n Ecology 19

ADAPTIVE

C H O O S E S

INDIVIDUAL

SUCCESS

ENVIRONMENTAL SELECTIVE FORCES

4>

INDIVIDUAL B

ADAPTIVE STRATEGY

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.

F o r e x a m p l e , an actor-based analysis o f the T s e m b a g a might e x p l a i n the ritual cycle o f p i g k i l l i n g described by R a p p a p o r t as s i m p l y 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 l i m i t e d resources available i n order to achieve power a n d 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 n u m b e r o f pigs that he contributes. T h e larger the n u m b e r o f animals he c a n k i l l , the greater the n u m b e r o f guests he can enter- tain a n d the larger the portions o f meat he is able to present to his guests, thus p l a c i n g them under greater o b l i g a t i o n to assist h i m i n the future. E a c h T s e m - baga m a l e therefore will seek to b u i l d up the largest h e r d that his family's labor force c a n support. O n l y when he reaches that limit w i l l he want to hold the feast a n d o n l y w h e n a sufficient n u m b e r o f m e n have achieved the desired n u m b e r o f pigs w i l l the c o m m u n i t y as a whole agree that it is time for the cere- m o n i a l slaughter. It m a y 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 p r o d u c t i v i t y degraded but, from the perspective of the actor-based model o f decision mak- i n g , this happy result is no more than the s u m m e d 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 , w i t h its emphasis o n the processes by w h i c h people make decisions about how to interact w i t h their e n v i r o n m e n t , is a valuable approach for u n d e r s t a n d i n g how change occurs in social systems in response to e n v i r o n m e n t a l perturbations. T h e approach is particularly useful for the insight it gives into w h y traditional farmers accept or reject a g r i c u l t u r a l i n n o - vations. A study by M i c h a e l M o c r m a n (1968) has, for example, helped to e x p l a i n w h y peasant rice farmers in northern T h a i l a n d have adopted tractors under certain e n v i r o n m e n t a l circumstances w h i l e they continue to rely o n 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 f e n v i r o n m e n t a l forces affecting crop yields.

These a n d other studies of i n d i v i d u a l decision m a k i n g have shown c o n v i n c - ingly that A s i a n peasants arc far from b e i n g the trad it i o n - b o u n d 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 a g r i c u l t u r a l innovations in terms of potential benefits a n d 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 m a y re- q u i r e high inputs o f fertilizer, pesticides, a n d water. These inputs are u n a v a i l a - ble to the poorer farmers, and m o d e r n c r o p p i n g methods are also m u c h more vulnerable to e n v i r o n m e n t a l hazards such as floods, droughts, a n d insect a n d disease outbreaks.

P o o r m a r g i n a l farmers, who arc barely able to eke out a l i v i n g with e x i s t i n g technology, simply cannot afford to take the greater risks of failure associated w i t h innovative means o f p r o d u c t i o n . R a t h e r than take b i g risks to m a x i m i z e i n c o m e , the farmer who has only I hectare (ha) o r 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 kilo- grams o f padi every year without fail than it is to harvest 3,000 k i l o g r a m s in favorable years a n d n o t h i n g i n years when e n v i r o n m e n t a l conditions are less favorable. F r o m this perspective, it is easy to understand why V i e t n a m e s e 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 agricultur- al innovations after their resettlement i n the M e k o n g Delta i n 1955. These peasants had not m i r a c u l o u s l y 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 " s i m p l y 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 c o u l d now afford to take the risks o f e x p e r i m e n t i n g o n part o f their land w i t h " 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, a n d even tractors, because failure no longer meant starvation. U n d e r new

Conceptual Approaches to H u m a n Ecology 21

e n v i r o n m e n t a l c o n d i t i o n s , these formerly conservative peasants q u i c k l y became a m o n g the most innovative farmers in V 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 e n v i r o n m e n t a l relations, it relies u p o n 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 o f choosing which o f two rice varieties w i l l give o p t i m u m yields under local e n v i r o n m e n t a l conditions cannot be taken as e v i - dence that h u m a n s in general always or even usually make correct decisions about their interactions with the e n v i r o n m e n t . In its assumption that h u m a n s always behave rationally, the actor-based model bears m a n y resemblances to the "free-market" model o f the classical economists who conceived of count- less independent i n d i v i d u a l decisions to buy o r sell as operating to produce o p t i m a l prices i n any particular supply and d e m a n d 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 a n d the deliberate m a n i p u l a t i o n s 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 uncrit- ically such an " A d a m S m i t h " conceptual approach w i t h the implicit assumption (hat i n d i v i d u a l farmers n o r m a l l y make their decisions in an ecologically rational way. A n d r e w V a y d a ( V a y d a a n d 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, n o w appears to take the position that i n d i v i d u a l s i n tra- d i t i o n a l 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 a n d detailed e n v i r o n m e n t a l knowledge, which can allow them to make rational decisions about resource use a n d 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 o l the c o m m o n s " described by G a r r i u H a r d i n (1968), the s u m m e d effect o f i n d i v i d u a l decisions, all o f w h i c h 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 c o m m u n i t y *

"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 per- sonal m a x i m u m gains. T h i s 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 the pasture is destroyed. Such a process can be observed currently in many upland areas in Asia.