Explaining the Gap: On Humans and Other

Animals – Essay Review

I.

Esteemed gentlemen of the Academy! You show me the honor ofcalling upon me to submit a report to the Academy concerning myprevious life as an ape.1

So begins Kafka’s short story ‘‘A Report to the Academy’’. Capturedon the Gold Coast by a hunting expedition, shot and limping andthrown into a cage between decks aboard ship, the ape named RedPeter soon learns that his only hope is to imitate his captures. ‘‘I couldalready spit on my first day’’, he recalls, and ‘‘soon I was smoking apipe like an old man’’. The greatest difficulty was with the bottle ofalcohol, the smell of which tortured him. But he forced himself with allhis power, and his keeper didn’t anger, realizing that ‘‘we were fightingon the same side against ape nature and that I had the more difficultpart’’.

Before long Red Peter was talking, and, in Europe now, singing atthe music hall where he fast became a sensation. With a personalimpresario at his call and beckon, and a courteously supplied half-trained female chimpanzee awaiting him to take his pleasure with her atnight upon retuning from banquets and scientific societies – (‘‘duringthe day I don’t want to see her’’, he admits, ‘‘For she has in her gaze themadness of a bewildered trained animal’’) – the ape turned man couldrise no higher. ‘‘I achieved what I wished to achieve’’, he reports to theaugust membership. ‘‘Alas, one learns when one has to. One learnswhen one wants a way out’’.

1 Kafka, 1917.

Journal of the History of Biology (2013) 46:739–755 � Springer Science+Business Media Dordrecht 2013

DOI 10.1007/s10739-013-9372-x

‘‘A Report to the Academy’’ was first published in 1917 by MartinBuber, in the German monthly Der Jude, of all places, alongside an-other of his stories, ‘‘Jackals and Arabs’’. One interpretation holds thatKafka was satirizing the Jews’ assimilation in Western culture.2 An-other, in J.M. Coetzee’s novel Elisabeth Costello, co-opts the ape forvegetarianism and animal rights. And Michel Gondry muses over theirreversibility of domestication in his 2001 filmHuman Nature, a CharlieKaufman adaptation (but not perhaps his best). Whatever Kafka’sdesigns, he captured the imagination: how different are we, really, fromour hairy, tree-climbing relations? Ever since the first apes made theirway to the West, it was a question that bedeviled modern humans.

Darwin, after all, had let the monkey out of the bag. ‘‘The senses andthe intuitions’’, he wrote in The Descent of Man, ‘‘the various emotionsand faculties, such as love, memory, attention, curiosity, imitation,reason, &c, of which man boasts, may be found in an incipient, and evensometimes in a well developed condition, in the lower animals’’.3 Inwhat became known as ‘‘the Great Hippocampus Question’’, two ofEngland’s scientific giants fought fist and knuckle over evolution’slegacy. Richard Owen, the ‘‘English Cuvier’’ and leading anatomist,would have no truck with the insipid transmutation of species. Humans,according to him, were not merely a distinct order of primates, but aseparate sub-class of mammalia. Based on anatomic comparisons of thebrains of Man, Negro, Monkey, and Chimpanzee, Owen concluded thathumans alone have a hippocampus minor – a small fold on the occipitalhorn towards the back of the brain. Together with a projecting posteriorlobe beyond the cerebellum and the presence of a posterior horn, thisunique feature accounted for the manner in which specially created man‘‘fulfills his destiny as the supreme master of this earth and of the lowercreation’’.4 Evolution, Owen held, is sacrilege.

‘‘Before I have done with that mendacious humbug I will nail himout, like a kite to a barn door’’, was Thomas Henry Huxley’s measuredreply.5 Determined to rid British science of its domination by wealthyclergymen and replace them with a salaried professional class of sci-entific civil servants, Huxley went at Owen, their champion, like abulldog. With his nemesis in the audience at his Croonian Lecture at theRoyal Institution in June 1858 and again during the meeting of theBritish Association for the Advancement of Science at Oxford two

2 Murray, 2004.3 Darwin, 1871, p. 126.4 Gross, 1993.5 Ibid., pp. 407–408.

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summers later, Huxley presented evidence in direct contradiction to theclaim that humans possessed unique anatomies of the brain. Owen, heoffered, was guilty of ‘‘willful and deliberate falsehood’’. Darwin rel-ished the takedown from the sidelines, congratulating his underling onhis ‘‘smasher’’ against the ‘‘canting humbug’’ Owen.6 Huxley, for hispart, proceeded to deliver a popular series of sixpenny lectures forworking men at the School of Mines on ‘‘The Relation of Man to theRest of the Animal Kingdom’’, assuring his wife as the course beganthat ‘‘By next Friday evening they will all be convinced that they aremonkeys’’.7

Owen would soon recant, albeit in a footnote and with little grace.8

But the fights over man’s special place in nature continued. Darwin’sargument for continuity famously rested on anecdotes: a clever pigeonhere, a loyal dog there, a curious monkey. Soon behaviorism wouldclaim to do better, systematically observing animals in laboratories.Men like Ed Thorndike and Ivan Pavlov concluded that what could beconstrued as intelligent behavior was actually the workings of simpleassociative learning rules; animals need not be imbued with species-specific mental capacities. Clever Hans, the sensational turn of thecentury German horse that seemed to be doing arithmetic by answeringquestions such as ‘‘how much are 5 + 7’’ with appropriately numberedtaps of the hoof, provided the proof in the pudding (or dung): close

6 Charles Darwin letter to T.H. Huxley, January 3, 1861, Darwin CorrespondenceProject.

7 ‘‘T.H. Huxley letter to Henrietta Huxley, March 22, 1861, The Huxley File,http://aleph0.clarku.edu/huxley/letters/61.html.

8 He called Huxley’s attacks ‘‘peurile’’ and ‘‘disgraceful’’ and continued to insist that

man be classified as a separate sub-class of mammal. See Owen, 1866. The satirists wentto town. Punch carried a poem by ‘‘Gorilla’’ (really the paleontologist Sir Philip Eg-erton), two stanzas of which read:

Says Owen, you can seeThe brain of Chimpanzee

Is always exceedingly small,With the hindermost ‘‘horn’’Of extremity shorn,And no ‘‘hippocampus’’ at all.

…Next Huxley replies,That Owen he lies,

And garbles his Latin quotation;That his facts are not new,His mistakes not a few.

Detrimental to his reputation.

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scrutiny uncovered, to the consternation of many and delight of others,that the beast was responding to subtle cues from its master, Wilhelmvon Osten, rather than manifesting equestrian genius. Animal intelli-gence fell from grace. But then, in the 1960s, a cognitive revolutionswept over psychology, and soon animals, too, were being thought of asgoal seeking agents that acquire, store, retrieve and process informationin the brain.9 Before long, ‘‘romantic’’ views of the mental life of ani-mals returned, challenging ‘‘killjoy’’ approaches that had come todominate. Do talking parrots have language? Are nut hoarding squirrelsthinking of tomorrow? Do chimpanzees contemplate the meaning of lifeas they scratch their human-like heads? The debates between rich andlean accounts of animal mentality continue, as fiercely as in Owen andHuxley’s day.

Which makes the appearance of Thomas Suddensdorf’s wonderfulThe Gap: The Science of What Separates Us from Other Animals all themore welcome.10 Suddendorf is a psychologist who has made a career,principally in Australia, of studying the behavior of animals and younghumans. In The Gap he brings to bare his learning to assess where westand today, scientifically, on the question of human uniqueness. Sur-veying language, mental time travel, mind reading, intelligence, cultureand morality, Suddendorf carefully weighs the evidence undergirdingromantic and killjoy interpretations. And he offers an intriguing theory:what sets us apart, above all, are two attributes – our infinite imagi-nation and our voracious appetite to bring our minds together. Beforewe consider the evidence, let’s linger one moment on actual brains.

Size, after all, as every one knows, does matter. And the brains ofsmall apes (siamangs, hoolocks, gibbons) weigh 80 g to our 1350. Evenour closer cousins, the great apes (orangutans, gorillas, chimpanzeesand bonobos) have brains but a fourth of our size, ranging between 300and 450 g. Nothing comes close to the 170 billion cells powering ourenormous brains, just 2% of our body weight but guzzling 25% of ourtotal energy. Nothing, that is, but elephant brains, or whale brains,which weigh 4 and 9 kg, respectively. If absolute size cannot account forthe gap, then perhaps relative size can; the only problem is that based onthat metric some shrews and mice come out ahead, quintupling ourbrain-to-body size ratio. Beaten on one scheme by large animals and onanother by little ones, scientists have devised yet a third, the encepha-lization quotient, or EQ, which takes into account that as mammals getlarger, their brains grow absolutely but become smaller in relative terms.

9 For a history of the earlier development of ethology, see Burkhardt, Jr., 2005.10 Suddensdorf, 2013.

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Here, finally, we do come up on top, except that capuchins top chim-panzees too, which leads to some head scratching. Suddendorf himself,together with Andrew Whiten, has devised yet a fourth metric, whichseems so far to make good sense, but even its authors are not certainwhether they’re not manipulating statistics to confirm their own pre-conceptions.11

Neuroscience has in recent years uncovered interesting differencesbetween human and ape brains at the micro-level; the finding, for in-stance, that the human cerebral cortex volume is 2.75 times larger than inchimpanzees but has only 1.25 times more neurons suggests that a goodchunk of the increased mass is due to the space between cell bodies, theneutropil, and the axons, dendrites and synapses that inhabit it and ac-count for our brains’ unique connectivity.12 But the jury is out over whatall this means. Until we achieve a greater understanding of brains, itremains unclear how physical differences account for mental ones. Toprobe human uniqueness more deeply, we need to turn to behavior.

II.

‘‘Speak and I shall baptize thee’’, said the Cardinal of Polignac uponencountering a one-year-old chimpanzee in the Jardin du Roi, or soDiderot reports. Indeed, well ingrained is the notion that it is languagethat makes us human; it was Noam Chomsky, battling the behaviorists,who helped spread this view in our times. After all, if language is ac-quired through simple associative learning rules, he argued, why thecritical period? Why the overgeneralization of rules, grammar univer-sals, and the apparent robustness of developmental stages? A mutation,perhaps just 100,000 years old, would have turned us humans, uniquely,into Homo linguisticus, accounting for our great leap forward and thegaping chasm between man and ape.

Not that our linguistic uniqueness had never been challenged.Richard Garner, immortalized in Hugh Lofting’s children’s series as theloveable Dr. Doolittle, set out in 1873 to capture primates speakingin the forests of Central Africa.13 But neither his youthful zeal nor

11 Whiten and Suddendorf, 2007.12 Ralph Holloway in the 1960s suggested that evolutionary changes in cognitive

capacity are due to brain reorganization, not just changes in size. More recently, Todd

Preuss has provided physical evidence. The data is summarized in Gazzaniga, 2012, pp.27–41.13 Garner’s story is wonderfully told in Raddick, 2007.

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Edison’s newly invented cylinder phonographs could save Garner fromultimate shame and ridicule; he returned with nary a piece of evidence,and a mute chimpanzee who promptly died, no words spoken.

It was nearly a century later, in the 1980s, that Dorothy Cheney andRobert Seyfarth claimed to decipher distinct calls for ‘‘snake’’, ‘‘eagle’’,‘‘leopard’’ and ‘‘human’’ among vervet monkeys at the foot of MountKilimanjaro.14 But there remains no evidence of vervets stringing suchcalls together, nor does it seem that their vocal communication tran-scends mere alarm calls.15 Worse still, neuro-stimulation of the peri-aqueductal gray has brought about meowing and growling in cats,shrieking and barking in rhesus monkeys, echolocating in bats, andlaughing in chimps and humans. Most animal vocalizations, in otherwords, may have little if anything to do with human speech, which isprimarily associated with higher cortical areas of the left hemisphericalbrain. Indeed, Suddendorf’s teacher Michael Corballis has argued thatsince great apes have good voluntary control of their hands, and handsignaling has the advantage of being developmentally cheep and highlyiconic – more so than speech where symbols tend to be random – lan-guage may have first evolved in the gestural, rather than cognitive,domain.16

Whether or not this is true, teaching apes sign language (they can’tspeak for lacking the voluntary facial and vocal fine motor control) hasproven, over all, disappointing. While singular apes can and have beentaught to recognize and use up to several hundred symbols, manyresearchers have come away concluding that the process reflects simpleassociative learning rather than a true understanding of the represen-tational function of words.17 Apes in the wild do not regularly teacheach other, nor point to anything, nor ask for the names of things, nordo those who are taught symbols in captivity seem to grasp the principleand seek to acquire more useful words. One researcher, for example,taught her chimpanzees to count up to 9 in Arabic numerals, but eachnumber took an equal amount of time to acquire.18

14 See Cheney and Seyfarth, 1990.15 Sophisticated communication systems do exist in nature, as instanced by the ability

of highly specific bee dances to indicate the size and direction of a food source.Invariably, however, such systems are restricted to the domains of food, alarm, territoryand mating, as is now thought of the (rather low information content) songs of

humpback whales.16 Corballis, 2011.17 Including the handler of the jocularly named but tragically fortuned Nim Chimp-

sky.18 Boysen and Hallberg, 2000.

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Still, there have been touching revelations. The gorilla Koko,responding to the question ‘‘Who are you?’’, signed the following on fiveseparate occasions:

1. Me gorilla nipples tickle2. Polite-Koko Koko nut nut polite3. Koko polite me thirsty4. Polite me thirsty feel Koko love5. Koko polite sorry good frown.

The self-reference is fascinating, especially considering the ability ofgorilla’s to recognize themselves in the mirror (an ability, by the way,entirely lacking in gibbons). But the utter lack of syntax is painfullyapparent, as well as the obvious lack of recursion, and arguments to thecontrary seem like a stretch. ‘‘They just don’t get it’’, Steven Pinkerconcludes, and most linguists and animal specialists concur.19

The Chomskian edifice is slowly crumbling; the idea of an innateuniversal grammar being challenged by the notion, as Suddendorfwrites, that ‘‘we culturally inherit a specific language from people who,based on more general capacities for embedding thinking, manage toestablish such symbols and rules for the practical purpose of exchangingthe matters on their minds’’.20 But whether language is an innate spe-cies-specific cognitive capacity or an evolving cultural tool, open-endedcommunication, it does seem to be uniquely human. However much wemight dream of it, no Red Peter has yet to address an academy.

III.

If not language, what about memory: Don’t animals have plenty ofthat? Scrub jays, for one, are well known to bury stashes of food towhich they return, and squirrels to hoard nuts for the coming winter.Dogs everywhere punctually await the morning mailman with waggingtails and pointed ears. We think of memory as uniquely human, butnature, it seems, begs to differ.

The thing about memory is that more than a system geared to thepast, it serves the present and future: as our fabulously fallible memories

19 Pinker, 1994.20 See in particular Everett, 2012, and look out for work by the linguist Daniel Dor in

months ahead.

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attest, natural selection seems to have developed this capacity in orderto boost fitness rather than accurately snap-shoot fast-dwindling by-gones.21 Consider this: the best predictor of future behavior is generallypast behavior, and brain-imaging studies have found that the sameareas of the brain are involved in recalling past events and imaginingfuture scenarios. Our ability to mentally time travel into the past andinto the future may just be two sides of the very same coin.

And yet episodic, as apart from procedural and semantic, memoryseems rather weak in other animals; and lean, rather than rich inter-pretations, therefore more convincing. Take the jays. Memory of theirstashes fades with time. Rather than assuming that they recall whereand when precisely they buried a particular one, Suddendorf suggeststhat the birds may simply learn when it pays to search out a stash byassociating the strength of their memory of its location with whether it isstill good to eat upon recovery. If so, a rule such as ‘‘worms are notworth searching for once the memory of their location has weakenedbeyond a certain point’’ would suffice, and an even simpler one wouldapply for birds and rodents who rely on just one type of grub.

Innate mechanisms as well as associative learning can be powerfulfitness boosters: young squirrels who have never experienced a winterhoard nuts all the same, and Pavlov’s salivating canines were preparingthemselves for anticipated food, not kvelling over past repasts. But in-nate mechanisms also lack flexibility. Just think of the digger wasp,which always inspects its nest before dragging in prey to feed its larvae.If the prey is moved a mere inch by a human, the wasp will drag it backto the entrance to drop it there before inspecting the nest once again,and will do so time and again without fail; if the entrance itself isdestroyed, the mechanical provider will not only forego feeding itsyoung, but will continually trample over them in search of the opening.

Associative learning, too, is limited and poorly generative, as eventhe most loving dog owner will countenance. Episodic memory, on theother hand, is closely coupled to foresight, which may be why humans,and not wasps or dogs, invented the myth of stealing fire from the gods(the name ‘‘Prometheus’’ means ‘‘foresight’’ in Greek). Just think of theway we humans can sail into an imagined future, foregoing sex (celi-bates) and even life (radical altruists and suicide bombers) for self-redemption or an unseen Shangri-La. Think more colloquially of ourability to imagine consequences, to weigh alternatives, to plan aheadand design technologies. Since foresight is so beneficial to fitness, onewould expect to find ample mental time travel capacities in other ani-

21 For an interesting take on this, see Trivers, 2011.

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mals, and yet there exists no strong evidence of future planning in thewild, no keeping of tools that have been refined, no greed, interestingly,as in humans, either. Oscar Wilde may have been the one to quip, ‘‘I canresist anything but temptation’’, but it is apes, not humans, who arenotoriously bad at deferring gratification. For a future reward fortytimes greater than one presented now, Suddendorf tells us, Chimpanzeeshold out for 8 min at best, gorillas for two.

Mental time travel may be crucial for our emotional lives as well asfor our inspiration, but our ability to get into the minds of others playsan important role, too. Take false belief tests, ingeniously first devisedby the developmental psychologists Heinz Wimmer and Joseph Pernerin 1983.22 The idea is simple: Danny places his candy on the counter,but when he leaves the room Lisa puts them in the cupboard; where willDanny search for his sweets when he returns? Before the age of threeand a half, most children will have Danny search out his candy in thecupboard, but older kids know better. In fact, children with older sib-lings know better earlier, suggesting that our social environment plays arole in our development of ‘‘theory of mind’’.

And theory of mind, alas, defines our existence. ‘‘Does she love me?Has he found out? What will her parents say, not to mention my mo-ther…?’’ Try to imagine junior high, or Wall Street or foreign policy orjust a conversation on a park bench with a stranger, for that matter,minus the ability to get into the mind of another. Life as we know itwould cease to exist. Sure, we have some useful allies: Language, asSuddendorf writes, turns mind reading into mind telling – a very happyinvention. But notice, too, how crucial eye contact is for guessing otherpeople’s intentions and moods: The eyes really are a window to the soul,which may help explain why congenitally blind children are typicallydelayed in passing theory of mind tests.

And yet animals almost never look each other directly in the eyeballs;a threatening gesture, such behavior is usually avoided.23 Not that thishas dissuaded researchers from trying to figure out whether animalsthink about what others think; for decades, killjoys and romantics havebeen at loggerheads interpreting experimental results. Certain data seemunequivocal, such as the finding that chimpanzees will beg for foodfrom someone with a bucket over his head just as much as fromsomeone who can actually see their desperate pleading. But consideranother example: Subordinate chimpanzees were found to approachhidden food more readily when the hiding location was switched while

22 Wimmer and Perner, 1983.23 Dogs and people present an interesting exception. See Harman, 2012.

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the dominant was not around as compared to when he was present. Thesame was true when the dominant actually saw the hiding, but was thenreplaced by another dominant who didn’t: again, the subordinate wasmore likely to go for the food when there was no chance that the presentdominant was aware of where it had been stashed. This looks like theoryof mind, but wait! Maybe it’s just simple observation of behavior.Minus a written or oral confession, perhaps like that of Kafka’s simianacademician, it’s difficult to know for sure. What is clear is that nononhuman animal has passed a false belief test yet.

Might all this just be down to intelligence, us humans having beenblessed with a greater quotient than all the rest? Turtles and birds andsharks navigate with the help of electromagnetic fields in ways that putto shame our best reconnaissance scouts, as do bats and dolphins viaecholocation. DARPA is spending billions trying to figure out just howto use optic flow, as in bees, for aircraft navigation, and it’s taken usmillennia to develop thermostats as sophisticated as those found intermite mounds.24 Still, remember the poor digger wasp, and considerthat all bees navigate, and termites build, in the very same manner. Theamazing abilities we behold in nature are universal in each species,narrowly genetically programmed. As far as we know, there are nosuper turtles who navigate better than all the rest.

Still, far from all animal behavior is pre-determined, of course. I oncespent a summer at the Marine Biological Laboratories trying to helpcuttlefish teach each other how to snag crabs, and, wouldn’t you know it– it worked (just partially, though feeding neurotic baby cuttlefishantibiotics to keep the experiment going was quite an experience!). In-deed, the evidence for animal learning is extensive, ranging from cleveroctopi to sagacious elephants.25 A current rock star is the New Cale-donian crow, which is able to make tools to gain other tools to yet othertools to even more tools to access a food reward; the test, devised inOxford by Alex Cacelnik and his colleagues, is jokingly referred to asthe Chancellor Test, since timed against the leader of the university, thebird comes out on top.26

Despite over a century of concerted efforts to crack the essence ofintelligence, no one really knows its structure. Still, there is a broadconsensus in the IQ testing community that intelligence involves threethings: the capacity to learn from experience, to adapt to the surrounding

24 ‘‘Bio-mimicry’’ and ‘‘bio-inspiration’’ are growing fields the world over, from zoos

to architecture firms to robotics labs.25 Pearce, 2008.26 Check out the video, here: http://www.youtube.com/watch?v=ZE4BT8QSgZk.

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environment, and to reflect on one’s own performance. There is littledoubt that animals – from corvids to cuttlefish to beavers to foxes – arecapable of various degrees of the first two of these, though learning, evenin great apes, often seems haphazard and trial-and-error-based ratherthan systematic and insightful. Suddendorf is right to state that theclassic antipodes betray a simplification: ‘‘Showing that a species be-haves in ways that cannot be explained by trial and error learning doesnot mean that they necessarily reason like a human being’’, he writes.‘‘Conversely, if animal behavior is not driven by humanlike reasoning, itdoes not immediately follow that it must be the result of some ‘mindless’associative learning alone’’. There is a great diversity of cognitive abili-ties out there awaiting more nuanced description.

And yet little evidence exists for animals thinking about thinking –what philosophers call metacognition.27 This may be a result of the factthat their working memory is simply not as strong as ours: it is variationin this capacity to hold and manipulate chunks of information in ourminds that accounts for differences in our own IQ’s, as much as half ofthe variability. The strength of working memory determines the numberof relations one can juggle simultaneously – as they manifest themselvesin anything from mathematical proofs to surfing to writing poems. Andsince storage and processing space are important for our ability toimagine multiple mental scenarios, integrate them into a narrative, andcompare and evaluate, language, mental time travel, and theory of minddepend on their umph. That we can think of the love between twopeople, a ceremony involving a ring, late night diaper changing, andgrowing old together, all under the banner of ‘‘marriage’’ allows us todecontextualize our thinking, abstract, and create metaphors. It allowsus too to build theories about theories, and search for truth.

Working memory is tough to gage in animals, since no non-verbalmeasure has yet to be invented. But as the philosopher Kim Sterelnyargues, the seemingly ‘‘laser-beam’’ intelligence sometimes exhibited byanimals is strongly contrasted by the ‘‘response breadth’’ of us humans– a general, non-domain-specific defining ability.28 That is why (at leastsome of us) can appreciate abstract modern art, aim for the stars in ourspace programs and minds, or lie our way out of a second helping ofspinach. We are, it seems, smarter apes after all. Which leads us to ourfinal considerations.

27 Suddendorf cites the work of J. David Smith with dolphins as a possible challengeto this view. For Smith’s own take, see Smith et al., 2012.28 Sterelny, 2012.

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IV.

‘‘I imagine hell like this’’, Peter Ustinov once quipped: ‘‘Italian punc-tuality, German humor, and English wine’’. Undoubtedly, culture is apowerful inheritance system, alongside our purely biological hand-me-downs.29 From cooking practices to literary and artistic fashions tosexual mores to senses of humor, it is both cornerstone and scaffold ofwho we are, as much as who we aren’t. Culture’s currency is informa-tion – visual, auditory, tactile, olfactory, taste-based – and whetherfamilial, communal, national or global; faith-based, aesthetic, radical orconservative – it depends on us for its propagation. Teaching and imi-tation are therefore its two pillars: The great Russian psychologist LevVygotsky had it right when he said: ‘‘Through others we become our-selves’’ (so did George Bernard Shaw: ‘‘Imitation is not just the sincerestform of flattery – it’s the sincerest form of learning’’).

But what about animal cultures: Do they even exist? Scholars argueabout using the term, some preferring ‘‘traditions’’.30 Call it what youmay, there is clearly learning and a lot of imitation going on. Just listento lyberbirds in Queensland, Suddendorf beckons us, giving spot-onrenditions of didgeridoos, camera shutters, and even beer can openingsin the wild. Or consider the two lone whales who in 1996 were recordedsinging their very own song, different from that of all the other males intheir pod: On their way back from the Antarctic the two gents hadpicked their song up from a different pod migrating up the western coastof Australia, and within two years virtually all the other males carriedthe tune. And of course, monkey see monkey really do: orangutans (notreally monkeys, actually) have been regularly reported to swing inhammocks, apply insect repellant, even sweep with a broom. Andchimpanzees seem to know precisely that they are engaging in copy-catbehavior, responding directly to ‘‘do this’’ commands.

‘‘Diffusion experiments’’ in fish, birds and mammals have shown thatbehavior patterns can spread socially. Naı̈ve pigeons, for example, learnhow to peck through covers of food more quickly when pigeons trainedto do just that are introduced into their enclosure as opposed to withoutthem. Adult Meerkats slowly introduce their young to eating scorpions,supplying killed ones first, followed by disabled ones with sting re-moved, before allowing them to hunt healthy ones on their own. Dol-phins break off sponges and wear them over their snouts when probingthe sea floor, the young learning foraging strategies from their mothers.

29 And, of course, it interacts with them. See Jablonka and Lamb, 2005.30 See Avital and Jablonka, 2000.

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Famously, a Japanese macaque named Imo started washing sand off ofpotatoes in the ocean (and, inter alia, perhaps salting them), a seeminglysui generis invention of dramatic culinary proportions. Before long, thegroup was happily doing the same – a quaint example of social learningthat made its way into all the textbooks. Animal culture, it suggested, isreal.

Except that Suddendorf reminds us that transmission, even in thisiconic case, was actually rather slow, rendering the appeal to culturesuperfluous if not downright misguided: Imo’s mom, it turns out oncloser inspection, learned the trick 3 months after Imo; 2 years later 7others had caught on, 3 years later 11, and a full 9 years later just 36 outof 49 were engaging in potato washing. Perhaps the invention wasn’t allthat spectacular after all, explaining its rather dawdling uptake. Whoknows. But in the case of meerkats, too, a more careful glance hasproven revealing. Playback studies showed that what is driving theparent’s behavior has more to do with their pup’s calls than with tai-lored teaching: when begging calls of older pups are played, parentsbring live prey even if their real pups are too young to deal with them,and dead prey to older pups when young pup cries are broadcast. Thebehavior looks at first like teaching, but seems to have little in commonwith the kind of flexible teaching we recognize in humans.

There are examples of non-biological inheritance in nature: Beaverdams, fox burrows, termite mounds – just like our own homes andinfrastructure – remain long after those who construct them are gone,impacting the environment of future generations. But social teachingacross generations and ‘‘culture’’ are another thing.

The picture emerging from the last half century of animal studiessince Imo suggests that while great apes can imitate, they don’t often doso, and functional teaching is really rather sparse.31 Traditions on theorder of a dozen or two have been argued to exist in great ape popu-lations, the Sumatran orangutans for example. But on the whole, ani-mals do not declaratively point out anything to one another, do notpersist in teaching, and exhibit none of the ratchet effect by which wediscover myriad solutions to problems and invent entirely novel pre-occupations. Lolicon cartoon magazines and Major League baseballreally are uniquely human.

So, when all is said and done, are the kinds of normative practices werefer to as morality. Yes, alongside great ferocity, chimpanzees exhibitconsoling behavior. Yes, rats have been shown to push levers at their

31 Suddendorf cites the work of the primatologist Christophe Boesch as a possible

exception that proves the point. See Boesch and Boesch, 1984.

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own expense in order to stop the suffering of mates. Empathy, it hasbeen demonstrated, is alive and well in the wild, especially widespread inprimates. But chimps, curiously, don’t share food either, hardly evenwith offspring. Nor do they exhibit any shame, nor, Suddendorf claims,apart from the occasional breaking up of scuffles by dominants, any realnormative policing (why dominants often do this is not clear: maybethey just want an end to all the raucous). Capuchin monkeys have beenshown, in a famously reported experiment, to reject cucumbers (lowvalue) as payment for a task when their mates are offered grapes (highvalue) for the same labor.32 Is this a sense of justice or just frustration?

Frans de Waal has devoted a lifetime to showing just how cooper-ative, empathetic, and political can be.33 Morality, to his mind, com-prises three components: the basic building blocks of empathy andreciprocity, the group pressures that keep individuals in line, and thecapacity for self-reflective moral reasoning. One might argue withSuddendorf’s lean-leaning interpretations of animal performance in thefirst and especially the second of these; the exertion of group pressuresand punishment seems to me more fundamental to great ape, as well asother social mammal, existence than he gives credit for. But even deWaal concedes that self-reflecting moral reasoning is the sole prove-nance of humans. And really, given the limits of language and inten-tional teaching, it is little surprise that no Marcus Aurelius or Ghandihas sprung up in the wild. No, an ape scratching his head contempla-tively on a log is probably not dreaming of a theory of justice.34

Yes, Darwin was right: the rudiments of many features that define usare to be found in nature – how else could it be? Great apes can rec-ognize themselves in the mirror, learn symbols, engage in pretend play,maintain complex social hierarchies, console, and, on a romanticinterpretation, exhibit a basic ability to entertain imaginary scenarios.But so can two-year-old humans, before their development explodes.What pushed communication over the brink to language, memory tomental time travel, social cognition to theory of mind, problem solvingto abstract reasoning, traditions to cumulative culture, and empathy tomorality? What helped give rise to our birthday party celebrations,philosophy journals, alcoholism, prison systems, confetti parades andcabal TV? The answer, Suddendorf claims originally, resides in twocrucial features: our open-ended, nested imaginations, and our insa-tiable drive to link our minds together. More than anything, these

32 Brosnan and de Waal, 2003.33 See Frans de Waal, 1996, 2007, 2009, 2013, among others.34 The debates about morality and its origins continue. See Harman, in print.

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features account for ‘‘the gap’’ between animals and humans.Consciousness remains a mystery. Whether an epiphenomenon or an

evolved, dedicated schematic model of one’s attention, or somethingelse, it was and is a game changer.35 But somewhere along the line wediscovered, too, that the accuracy and usefulness of our mental sce-narios could be dramatically improved by linking them, through lan-guage and culture, to other minds. Not just for food, or to soundalarms, or garner sex. We care deeply about what others think andactively seek their council. Unlike apes, we seem to have a ‘‘sharedintentionality’’,36 and autistic people, who don’t, face enormous chal-lenges.37 This dynamic between internal and external, subjective andsocial, created powerful feedback loops, carrying us where animalscould not go.

It is also reflected in our development. Bipedalism required thenarrowing of the female pelvis and hence more growth post-natally: thebrains of human babies are only 28% of their adult size, compared to40% in chimpanzees – a differential uniquely preparing us to cross theculture gap. Helpless and far from fully formed, we are in need of bothour parents, or at least more than just mom alone, and our high new-born survival rates reflect this (even the seemingly low figure of 50% fortraditional, pre-Western, hunter gatherer communities is much higherthan the 38% of chimpanzees, not to mention 15% for lions). We re-main dependent longer and reach sexual maturity late. And while theperiod between weaning and puberty is extended both in gorillas andchimps as well as humans, we alone experience adolescence with itsburst in skeletal growth, hormonal havoc, and increased sensationseeking and rebelliousness. As is now becoming clear, adolescence isalso a period when dramatic synapse pruning and axon mylenationoccur, among other changes to our brains.38

So are we different from animals? Of course: Owen’s gaffs notwith-standing, Red Peter ultimately provides a contemplation on our dif-ferences more than our similarities. There is a gap, and one worthstudying. As Suddendorf warns, in his important and beautifully writtenbook, it is also worth safeguarding: the more we hunt our closest rel-atives and ruthlessly destroy their habitats, the more unique we willseem to ourselves, betraying not only our selfishness but our origins.

35 For a recent interesting take see Graziano, 2013.36 See Tomasello et al., 2005.37 Suddendorf was part of a team that suggested that autism is an imitation disorder

related to impaired functioning of mirror neurons. See Williams et al., 2001.38 Bainbridge, 2009.

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Will the gap grow? It’s tough to know. What global connectedness,genetic engineering, and transhumanism will do to us might just as wellbe left to prophets and fools. But if we began with Kafka, we might aswell give the last word to Woody Allen: ‘‘Life is full of misery, loneli-ness, and suffering’’, he protests, ‘‘and it’s all over much too soon’’. Iwonder if an ape ever felt the same.

Oren Harman

Bar Ilan University

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