dogmatism, its willingness to look to adjacent schools ofbehavioural science. Thus, I was delighted to see Pavloviandogs and Skinnerian rats acknowledged as playing theirpart in the grand synthesis. The study of human memoryforms another of the book’s links with psychology.In summary, be forewarned: the neurobiology will not

be easy going and there are limits to the scope of theintegration. However, these do not detract from the valueof this ambitious book.

FREDERICK TOATESBiological Sciences,Open University,Milton Keynes MK7 6AA, U.K.

ANIMAL BEHAVIOUR, 68, 1224

doi:10.1016/j.anbehav.2004.03.002available online at http://www.ScienceDirect.com

Comparative Vertebrate Cognition: Are Primates Superior toNon-primates? Edited by LESLEY ROGERS & HSELAKAPLAN. Dordrecht: Kluwer Academic/Plenum (2004).Pp. xv+386. Price £87.00 hardback.

In the late 1990s Marler (1996) posed the question ‘Areprimates smarter than birds?’ in relation to socialcognition. Now this volume of papers edited by LesleyRogers and Hsela Kaplan asks ‘Are primates superior tonon-primates?’, in relation to cognition in general. Thebook is a timely response to two developments in cog-nitive research. The first is a closer examination of pastassumptions and anecdotes about primate cognition (e.g.Povinelli 2000). The second is the growing evidence thatnonprimates, in particular corvids (Emery, in press), mayhave cognitive skills that rival, or even surpass, those ofprimates.At first glance the title may seem a little provocative, but

the editors stress that their aim is not to undermineprimates, primatologists or primatology. Quite the reverse.The book is an attempt to enhance and to progressprimate study by emphasizing the need for scientificrigour and the benefit of comparative research extend-ing beyond these species. Marler posed his question fromoutside of primatology and therefore his work probablywent unnoticed by most primatologists. Rogers & Kaplanask their question as part of a series of books entitled‘Developments in Primatology: Progress and Prospects’.It is posed from firmly within the discipline and as aconsequence is bound to be read by many more pri-mate researchers. Indeed, the book should be read byall those involved in cognitive research for a valuableupdate on the field, especially if they are not yet con-vinced of the benefits of a comparative approach. It alsoacts as a necessary, but gentle, reminder that we shouldnot form any preconceptions when it comes to animalminds.Why has primate research been rather ‘closed’ and

lacking in comparative methods and rigour? In the pre-face, Rogers & Kaplan think that the reason is partlybecause of a belief that nonhuman primates needed to bepromoted as ‘special’ (i.e. better, with minds closest to

human minds) to encourage their conservation. Not allbold statements about primate cognition, though, arelikely to have been made because of conservation motives.They argue convincingly that such an approach canactually be detrimental to primate study and conserva-tion. A scientific approach to the study of nonhumanprimate cognition should do nothing to reduce the specialrelationship between these animals and ourselves. Theyare our closest living relatives, and that is reason enoughfor humanity to spend every effort to ensure their survivalin the wild.

Emery & Clayton (chapter 1) think that two combined,but faulty, concepts further help to explain the reason forthe so-called ‘primatocentric’ nature of cognitive researchon primates and on animals in general. The ‘intelligenceby association’ fallacy is that because primates are ourclosest surviving relatives, their cognition must be moreadvanced than that of nonprimates. The ‘intelligenceby evolutionary rank’ fallacy is that all species can beranked on a continuous scale in cognitive skills. Theseways of thinking have helped form the general impressionthat chimpanzees are also our closest surviving cogni-tive cousins, an assumption that Nissani (chapter 7)says cannot be made on currently available evidence. Allcognitive researchers need to think carefully aboutwhether they adhere to these two concepts.

The advantages of comparative study should not be indoubt, whether it is in relation to primate or nonprimateresearch. After all, it is how Darwin and Wallace shapedtheir theories on the evolution of species. It is certainlynot a new idea in cognitive research either as the excellentwork of people such as Shettleworth (1998) demonstrates.

The book is divided into five sections: complex cogni-tion, social learning, communication, theory of mind andthe brain. Each section has two papers, making a total of10 papers in all. Shettleworth broadly defines cognition toinclude ‘all ways in which animals take in informationthrough the senses, process, retain and decide to act on it’.There are of course many thousands of species each witha unique complement of cognitive skills. This volume ofpapers provides a glimpse of the cognitive abilities ofnonprimates in the form of representative comparativecase studies.

Emery & Clayton begin the section on complex cogni-tion with an excellent and thought-provoking summaryof differences and similarities between birds and primates.The authors examine seven claims of superior status forprimates that include brain ratios, social learning andmemory skills. They find that many of the claims alsoapply to birds, especially corvids, which sometimessurpass primates in certain abilities such as tool manufac-ture and memory. However, self-awareness and a theoryof mind appears to be a hard nut to crack for the avianbrain. Emery & Clayton admit that a full comparisonbetween birds and primates based on identical cognitiveskills is a long way off. They strongly advocate use of theecological/ethological approach (EEA) in cognitive re-search as one means to that end. This approach providesa more natural and realistic environment in which toconduct experiments to avoid potential problems thatcan occur in laboratory situations. To extend this

BOOK REVIEWS 225

further, knowledge of behavioural ecology in the wild,not just testing in the laboratory, can help to revealcognitive mechanisms (Shettleworth 2003). Vallortigarafollows with an examination of visual cognition in pri-mates and birds. He finds little basic difference betweenthe two groups, which he suggests should not be sur-prising as they face similar environmental problems.Vallortigara also reminds us that birds have independentlyevolved characteristics such as bipedalism and parentalcare.The debate about primate superiority becomes more

controversial in the section on social learning. Chapter 3by primatologists Box & Russon concentrates on a com-parison between monkeys and apes. It is one of the leastcomparative in its reference to nonprimates, which doeslittle to dispel the general perception of a primatocentricfocus in primate research. There is only a one-sentencereference to behavioural traditions in nonprimates, inwhich the evidence is dismissed as being ‘suggestive’.Admittedly, social cognition has received far less attentionin nonprimates than in primates. Nevertheless, ‘sugges-tive’ could be the pot calling the kettle black giventhat the evidence for traditions in primates (e.g. Whitenet al. 1999) is mostly circumstantial, as van Bergen,Laland & Hoppit state in chapter 4. In fact, Laland &Hoppit (2003) have said that the only scientificallyproven traditions are in nonprimates. van Bergen andcolleagues look at evidence for this line of argumentin fish and find ‘.stronger empirical evidence for culturein fish than in primates’. They are critical of discussionsof traditions in the primate literature because they gene-rally ignore work on nonprimates. They also urge peoplestudying primate cognition to consider a comparativefocus whether they are interested in general processes orprimate behaviour.Newman, who presents the first chapter on communi-

cation, reminds us that not all cognition is so-called‘higher cognition’. He examines the not-so-well-studiedarea of infant isolation calls and also finds that primatesare not superior to nonprimates. Kaplan tackles referen-tial signalling and communication associated with hunt-ing. It seems that for meaningful vocal and nonvocalcommunication, birds and nonprimate mammals havebehaviour that is similar in complexity to that of pri-mates. Primates fare little better in hunting coordina-tion than do animals such as wild dogs. Kaplan alsofinds little to suggest that signal complexity correlatesclosely with cognitive ability. However, she acknowledgesthat ‘higher cognition’ and signal complexity do co-occur in animals such as apes, corvids, wolves and somedolphins.Nissani and Call, in chapters 7 and 8, respectively,

investigate the thorny issue of whether or not nonhu-mans have a theory of mind. Nissani uses chimpanzeesand elephants to investigate insight and the attribution ofmental states to others. He finds a glimmer of hope thatboth species may attribute mental states, but suggests thatsigns of insight could also be due to trial-and-error. Callfocuses on attention in dogs and also chimpanzees, andfinds more evidence for this in the latter than the former.However, he cautions against simple explanations (e.g. in

the case of dogs) until they are well verified empirically.The search for consciousness is far from over, and newmethodologies may be needed to get definitive answers, asNissani laments.On arriving at the final section dealing with the brain, it

should be no surprise that Rogers in chapter 9 finds thatthe road to ‘higher cognition’ can have alternative routes.In fact, one of the most convincing arguments for thevalue of comparative study would be the evolution of‘higher cognition’ in birds and primates. This occurredindependently through brains that are very different insize and structure, but that may have evolved in responseto similar selection pressures. For example, Rogers notesthat mosaic evolution of the mammalian brain has beenan important aspect of its adaptive radiation, and this hasrecently been shown for the avian brain (Iwaniuk et al., inpress). As Emery & Clayton point out, avian and primatebrains represent a case of divergent neurological evolutionbut convergent cognitive evolution. In the final chapter,Hook looks at the brain in relation to lateralized motorfunctions and asks when they evolved. She examinesa range of functions that include whole-body turning,hand preferences and production of emotional responsesand vocalizations. As for many of the aspects covered bythe previous chapters, primates do not seem to be superiorin hemispheric specializations, which Hook finds alreadyexist in nonprimates. However, primates are superior inthe level of their coordinated bimanual skills and that maybe important when investigating the extreme handednessin humans.So, are primates cognitively superior to nonprimates?

Marler concluded that there were more similarities thandifferences between birds and primates. The currentvolume provides ample reason to continue to questionpast assumptions about the abilities of primate andnonprimate minds. An animal mind is capable of a multi-tude of cognitive skills. Primates outperform nonprimatesin certain areas, and are outperformed by nonprimatesin others. Research may still find, though, that themind of a chimpanzee is the most similar overall toa human mind. An important message for scientists tograsp is that there is no a priori reason why a nonprimatecould not have evolved a mind superior to that ofa chimpanzee.

GAVIN HUNTDepartment of Psychology,University of Auckland,Auckland 92019, New Zealand

References

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Iwaniuk, A. N., Dean, K. M. & Nelson, J. E. In press. A mosaic

pattern characterises the evolution of the avian brain. Proceedings

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Laland, K. & Hoppit, W. 2003. Do animals have culture?

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Marler, P. 1996. Social cognition: are primates smarter than birds?

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Shettleworth, S. J. 2003. Memory and hippocampal specialization

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Whiten, A., Goodall, J., McGrew, W. C., Nishida, T., Reynolds, V.,Sugiyama, Y., Tutin, C. E. G., Wrangham, R. W. & Boesch, C.1999. Cultures in chimpanzees. Nature, 399, 682–685.