1562 Animal Behaviour, 36, 5

tive approach pioneered, decades earlier, by Heape (1931). This self-imposed loss had arisen largely because students of the different groups seemed to consider they had little to learn from animals other than their own. Such chauvinism eventually reached the stage where ornithologists, entomolo- gists and human biologists not only used different definitions of migration but, in the case of ornitho- logists and entomologists, used definitions that were downright contradictory. As a springboard for return to a comparative approach via a com- mon terminology, I suggested a definition of migration (i.e. the act of moving from one place to another) not very different from that used here by Lasker & Mascie-Taylor. However, positions were entrenched and, in the years that followed, this definition attracted much unfavourable comment (e.g. Swingland & Greenwood 1983; Kennedy 1985). Rather than defend my definition yet again, I draw the attention of critics to Lasker & Mascie- Taylor's Introduction. 'Movement from one place to another' is still the only common denominator to all definitions of migration and, as shown by this book, is the definition being used by at least one large faction of migrationists.

Although the definition of migration used by Lasker & Mascie-Taylor gave me satisfaction, I found the rather innocent way in which the defini- tion was stated both symptomatic and sad. The Introduction makes no reference to the heated discussion going on amongst other migrationists, emphasizing yet again how distant is the day when students of the different animal groups, including humans, see value in each others' results and discussions. First, they will need to be prepared to adopt a common terminology.

It is, of course, most unfair of a reviewer to criticize a book for not being about something else. My defence is that, i f I were reviewing this book for Human Genetics or Human Biology, etc., I should offer little but praise. Subjects range from discus- sions of the origins of human diversity (K. M. Weiss) and the peopling of Australia and America (W. S. Laughlin and A. B. Harper) to a welcome review of the enigmatic rural-to-urban migrations (B. Bogin), interspersed with, among others, details of inter-island migrations (P. D. Raspe) and the problems of working from written records (D. F. Roberts). Throughout, the standard of discussion and description is excellent, revealing a consistency that is probably a tribute to the editors as well as to the authors. I suspect, however, that most readers of Animal Behaviour will find this a book for general interest, rather than one to help them extend their understanding of animal migration.

R. ROBIN BAKER

Department o f Environmental Biology, School o f Biological Sciences, University o f Manchester, Manchester M13 9PL, U.K.

References

Baker, R. R. 1978. The Evolutionary Ecology of Animal Migration. London: Hodder & Stoughton.

Baker, R. R. 1982. Migration: Paths through Time and Space. London: Hodder & Stoughton.

Heape, W. 1931. Emigration, Migration and Nomadism. Cambridge: Cambridge University Press.

Kennedy, J. S. 1985. Migration, behavioral and ecologi- cal. In: Migration: Mechanisms and Adaptive Signifi- cance. Contributions in Marine Science. Vol. 27 Suppl. (Ed. by M. A. Rankin), pp. 5-26. Port Aransas, Texas: Port Aransas Marine Laboratory.

Swingland, I. R. & Greenwood, P. J. (1983) Preface. In: The Ecology of Animal Movement (Ed. by I. R. Swingland & P. J. Greenwood) pp. vii-viii. Oxford: Oxford University Press.

Social Learning: Psychological and Biological Per- spectives. Edited by THOMAS R. ZENTALL BENNET G. GALEF, JR. Hillsdale, New Jersey: Lawrence Erlbaum (1988). Pp. xi+357. Price $45.00 hardback, $24.95 paperback.

Learning in animals is still studied primarily in the laboratory, in individual animals exposed to unna- tural conditions, which include in most cases social isolation during the experiment. One excusable reason for this is that it is easy to observe individual learning in these circumstances, while more natural and social behaviour is open to a greater variety of interpretations. Less excusable is the assumption, going back to Thorndike, that learning in animals is fundamentally asocial. Now that many other cherished beliefs of traditional learning theory in psychology have fallen to a greater awareness of ethological and ecological influences, it is appro- priate that the asociality assumption should be re- examined, and Zentall and Hogan have assembled what amounts to a survey of recent experimental evidence which challenges it.

Galefs introduction provides a rigorous and comprehensive classification of mechanisms of 'local enhancement', 'contagion' and so on, which are alternatives to more cognitive forms of imi- tation, and all the chapters exhibit commendable methodological care. There is comparatively little theoretical analysis: but Boyd & Richerson present mathematical models which imply that only highly variable environments require individual learning, speculating that many species across a wide range

Book Reviews 1563

of taxa inhabit environments where acquiring information from others is a superior strategy to those of exclusively individual learning or inherited control.

The experimental results suggest that the content of what is learned socially will follow fairly predict- able channels. Most impressive is the data on avoidance. Young rhesus monkeys acquire an intense fear of snakes on seeing their parents react fearfully to them: experimental controls here involve carefully edited videotapes and suggest that snakes can be regarded as a prepared conditioned stimulus (by comparison with flowers) with the model's fear display a Pavlovian unconditioned stimulus (Mineka & Cook). Curio similarly regards a dummy Australian honeyeater as a good condi- tioned stimulus, for blackbirds, with the mobbing response of another bird (to a dummy owl on the other side of a screen) as an unconditioned stimu- lus. More surprisingly, red-winged blackbirds will learn in one trial to avoid an orange food hopper after merely observing another bird experience malaise after eating from it. Mason shows, with this technique, that complex reddish stimuli are better than simple green ones, but has not yet isolated the critical features of the social cues indicating malaise.

Galef, Zentall and Denny et al. find relatively little evidence for any social learning in the labora- tory rat, beyond good olfactory detection of what another rat has been eating (Gale0, but Lefebvre & Palameta suggest that feral pigeons, being gregar- ious and opportunistic, use observational learning for action selection in foraging, their test being a paper-piercing response, with controls for five less demanding alternatives, such as learning of reward availability. Exploitation of fast-food remnants by London pigeons was noticeably rapid, and one notes that in Boyd & Richerson's theories, social learning is discounted not, clearly, in changing environments per se, but only in cases where the social models encounter different contingencies from those which pertain for the imitator. Petrono- vich and Pepperberg discuss vocal learning in the white-crowned sparrow and an African grey par- rot, respectively, agreeing that socially active tutors are more effective than tape-recordings or other less interesting sources, but saying little about the functional significance of avian vocal mimicry.

Rozin discusses socialization and human food preferences, which are obviously culturally deter- mined, and also to some degree irrational and Pavlovian, toilet training providing, he suspects, the foundation for all later strong disgust. Both Mazur and Meltzoff review their experimental work on imitation in human infants, which sug- gests that Piagetian and other theories of cognitive

development (notably Chomsky's) have under- played social learning in "Homo imitans'.

Much of the experimental work reported here is recent, or not conveniently available in journals, many of the chapters include useful literature reviews, and the paperback edition is very reason- ably priced.

STEPHEN WALKER Department of Psychology, Birkbeck College, Malet Street, London WC1E 7HX, U.K.

New Directions in Ecological Physiology. Edited by MARTIN E. FEDER, ALBERT F. BENNETt, WARREN W. BURGGREN & RAYMOND B. HUEY. Cam- bridge: Cambridge University Press (1988). Pp .x+364. Price £30.00 hardback, £12.50 paperback.

As scientists reach the end of their productive career they frequently slip into what Don Griffin has termed a philosopause. This state is character- ized by a retrospective view of how their research has followed a single path towards a better under- standing of The Scheme of Things or, in its worst manifestation, of The Human Condition. It is much less common for a group of the most active research workers in their field to take time off to review the State of their Art. Twenty-four of the world's leading ecological physiologists, 22 of them from the U.S.A., have produced an edited volume which does just that. I had long wondered what ecological physiologists were striving to achieve, and now I know. They want to understand physio- logical diversity. Their problem is to define the perspective from which they want to understand it. Do they want to understand its genetic basis, its evolutionary origins, its adaptive significance, or its nuts and bolts? There is no single answer since different ecological physiologists are asking differ- ent questions.

If one person can be said to have spawned and subsequently influenced the whole field, it is George Bartholomew. He has had an extraordi- narily long and productive research career, and has produced many good students along the way. And he has not stopped yet. With its perspective, vitality, simplicity and clarity, his chapter in the book is an absolute must. He continues to focus on animals in extreme environments arguing that 'an analysis of the mechanisms by which animals have successfully adjusted to the rigors of their habitats can provide the investigator with unusually reveal- ing insights concerning adaptive modification of the fundamental patterns of physiology character-