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Back to the wild
COVER STORY
Back to the wild 100 babies. No adults. One island. What would happen if humans grew up without culture, asks Christopher Kemp
30 | NewScientist | 6 June 2015
FRANK SCHERSCHEL/Time & Life/Getty
T
HE island is a strange place. Overgrown, unpredictable, war-torn. For hours during the day, the sun climbs into the sky and it is quiet and peaceful. But later, as the shadows gather in the trees, a volley of hoots erupts from the forest canopy and echoes around the island. Moments later, an answering call bursts from a thickly wooded valley on the other side of the island. A call, and then a response. And then silence. The sound comes again across the tops of the trees. Hooting, and then distant replies. High-pitched and repetitive, the sounds are not words. But they mean something anyway: the hunters are coming home. They emerge one by one from the foliage, stepping out cautiously into a wide and sandy bay. There are five of them, all males. Their bodies are lean and powerful. They carry a few simple tools – hammerstones and sharpened sticks and bones. At the end of the bay, they meet another group of hunters. Gesturing to one another and making primitive sounds, the two groups become one. They make their way to an encampment near the tree line where the women and children wait for them. This is one of the tribes on the island. But the island is not real, and neither are the hunters. There is no encampment or waiting group of women and children. They are all just outcomes of a thought experiment. It goes like this: many years ago, a coldhearted and amoral scientist placed 100 babies on an uninhabited but fertile island, half of them boys, half girls. He provided only the minimum requirements to keep them alive. He left them food and water, being careful not to be seen. He kept them from harm, when possible. For years, the children received none of the trappings of a normal upbringing: no language, no education, no culture. Later, he slowly began feeding and watering them less and less, until eventually he gave them nothing at all. After 20 years, what have they become? How different are they from us? Are they merely hairless apes, or have they retained qualities that make them unquestionably human? Or, to put it more succinctly, when humans grow up without culture, do they invent it anyway?
In the six million plus years since the human lineage split from chimpanzees, evolution has endowed us with many of the attributes that make us who we are: bipedalism, hairlessness, opposable thumbs, extended childhood and a large and complex brain. But these features alone do not make us human. Many of our defining traits – such as language, art, technology, storytelling and cooking – are transmitted culturally. Although products of our biology, they are not fully encoded by genes. Instead, they pass from generation to generation by social learning, evolving as they go. The relative contributions of these two forces – biological and cultural evolution, also known as “nature” and “nurture” – have been debated for centuries. How much of our humanity is hardwired, and how much of it depends on the culture in which we are raised? Are language and religion innate, for example? Are we born violent? Disentangling biology and culture is difficult. They interact and reinforce one another. But there is an experiment that would help tease them apart. It can’t be done in the real world, for ethical reasons. But it is possible to speculate, in the form of a thought experiment. Welcome to the island. >
Creatures of culture Many of the defining traits of our species are the products of cultural as well as biological evolution. Here are some of the important milestones 3.3 million years ago
Earliest stone tools, discovered close to Lake Turkana in Kenya
2 million years ago
Earliest plausible date for primitive language ability
1 million years ago
Ash and burned bone in Wonderwerk cave in South Africa are suggestive of fire and cooking
790,000 years ago
Earliest compelling evidence of controlled use of fire, at Gesher Benot Ya’aqo in Israel
430,000 years ago
Engraving on a shell found in Indonesia could be the earliest art
170,000 years ago
“How much of our humanity is hardwired, and how much depends on culture?”
Genetic evidence from lice suggest that humans were wearing clothes
120,000 years ago
Two skeletons in Israel are the oldest evidence of deliberate burial of the dead
100,000 year ago
Traces of ochre and fat found in two shells in Blombos cave, South Africa, were probably body paint From top: M. Chazan; Wim Lustenhouwer
6 June 2015 | NewScientist | 31
clean slate gesture. I think they would probably use calls. There are obvious reasons that verbalisation is effective: you can call people from afar; you can alert many people at once.” So, the island’s first inhabitants, when they grow up, might well hoot to one another. Their vocalisations could travel across the treetops. Even more interesting, says Senghas, is the linguistic development she expects will take place in subsequent generations. It will happen relatively quickly. Within a few generations, she says, the islanders will be speaking their own unique language. To support her claims, Senghas points to research on song traits in zebra finches, which suggests that the birds’ vocalisation – and probably that of humans too – is genetic in origin, and later shaped by environmental factors. “Only the male sings,” Senghas says, “and the juvenile males learn their song from their fathers.” If juvenile male zebra finches are raised in the absence of adult males, they fail to learn their signature song, but sing nonetheless. “They develop some wacky, spooky song that doesn’t sound like a natural zebra finch song,” says Senghas. “It sounds a lot like white noise.” When those juveniles reach adulthood and mate, they attempt to teach their offspring their strange discordant song. But something incredible happens: “The next generation produces something a little more like natural zebra finch song,” says Senghas. And the generation after that produces something closer again. “It only takes five generations before you’ve got the full-fledged thing.” The first generation of island dwellers might not develop a language, but their brains have
So after 20 years, what have those babies become? We cannot know for sure. But our thought experiment can draw on work from various scientific disciplines, including studies of hunter-gatherers, the evolution of bird song, the development of sign language and research on children raised in orphanages. No one person can supply a complete answer, and many scientists are unwilling even to speculate. Some called the project wild and provocative, others fanciful and incoherent. One potential source dismissed the exercise as “undergrad stoned talk”. Others, though, were enthusiastic to imagine possible outcomes. “My work is in language, so I’ve thought about this a lot,”
says Ann Senghas, a psychologist at Barnard College in New York City who studies sign language in a population of deaf Nicaraguan children. The language emerged spontaneously in a school for the deaf that opened in Managua in 1977, and is now passed down from generation to generation, rapidly evolving like any spoken language. It is linguistic gold dust because the signers have never learned a spoken language or to lip-read. But they invented a language anyway, one that now has the complex linguistic hallmarks common to all others. This, says Senghas, supports the theory that the brain possesses structures that hardwire it for language. In the 1960s, linguist Noam Chomsky proposed that humans are born with a “language acquisition device” – a hypothetical brain module that predisposes us to learn the languages in which we are immersed as babies and toddlers. And it seems that when the language acquisition device never encounters language, it invents one from scratch. So would the first generation of island dwellers speak? “Some people would think because so much of language is innate, that the first cohort would just have it right away, somehow,” Senghas says. “But I don’t think they would.” Although they would, like the Nicaraguan children, invent ways to communicate. “The first generation of those kids would develop certain ways of getting messages across nonverbally,” says Senghas. “I’m betting they would at least come up with the idea of using 32 | NewScientist | 6 June 2015
Tal Paz-Fridman/Plainpicture
“In many ways, the first generation on the island is still distinctly human”
all the necessary structures and neural pathways. Like a juvenile zebra finch building on its father’s atonal song, each successive generation of islanders will possess and develop more language than the last. “I think it would take a couple of generations,” says Senghas, “but not many to develop a language that’s as rich and developed as anything that we have.” This is a crucial breakthrough for the islanders. Once in possession of language, cultural transmission of ideas becomes easier. After they start to speak, says Ian Tattersall, a palaeoanthropologist at the American Museum of Natural History, they begin naming things. Eventually, the islanders begin to do something all human cultures do, and which probably emerged not long after sophisticated language did, perhaps 200,000 years ago: they name each other. In many ways, our first generation is still resolutely human too. Even in the absence of culture, millions of years of biological evolution has endowed them with a complex brain and many distinctly human traits. They do not become mere apes overnight. In fact, says Dominic Johnson at the University of Oxford, who uses evolutionary theory to study conflict and cooperation, if a Martian zoologist visited Earth to study its inhabitants, the islanders would provide better and more instructive examples of Homo sapiens than we do. “Our physiology and behaviour were designed for life in the wilderness with scarce resources and a few dozen or so other people,”
Roy Toft/National Geographic/Getty
he says. “That’s our natural habitat. We are certainly not designed for life in modern megacities with fast food on every corner.” In time, says Johnson, the islanders might begin to resemble modern hunter-gatherer groups. “Hunter-gatherers provide a window into our human nature and the things that emerge spontaneously in human organisations when they’re not surrounded by modern culture,” he says. For instance, the islanders are likely to invent tools and use them for many tasks. In the beginning, the tools are simple, developed by trial and error. Swung with determination, a heavy rock is a tool. A broken rock, with a sharp unfinished edge for cutting, is a better tool.
Tribe and error The island ecology will play its part too, says Johnson. Tribal groups in New Guinea and Tibet are vastly different to one another, their lives shaped fundamentally by their surroundings. For tools, the children can use only what they find on the island. Perhaps they will learn to fashion fish hooks from bone. They can harvest and eat only what grows there, and hunt only the animals endemic to the island and its waters. In time, by trial and error – and by making costly mistakes – they learn what is good and safe to eat, and they pass that knowledge on to each other and to their offspring. They will be willing experimenters, and even more willing learners. Humans seem to have an evolved tendency for individual
learning and copying, especially of successful individuals. In this way, culture gradually improves and spreads, with new discoveries building on previous ones. Unlike groups that live in cold or mountainous places, the islanders go naked: they have no need to invent clothes. Whatever their environment, the islanders will adapt to it, says Val Curtis, a behavioural scientist at the London School of Hygiene and Tropical Medicine and co-author of Gaining Control: How human behavior evolved. “Brains are learning machines,” says Curtis. “Our minds come pre-equipped with structure that allows us to learn to behave adaptively.” For example, if the children have to crack a nut, they intuitively understand that a rock will allow them to do it quickly. “I predict that our abandoned kids will soon have their environment mapped and will figure out where to find or make shelters, beds and tools,” says Curtis. Each tool they develop will be a little more sophisticated than the previous one. “But you know what?” says Senghas. “It’ll be a long time before they figure out the wheel.” The mastery of fire and the development of simple machines like ramps and pulleys will take thousands of years, says Senghas – the same amount of time as it took humans to invent them the first time. “Generating things like levers and wheels and fire and cooking involved work and experimentation, and getting so far and then being able to pass that down culturally to the next generation,” she says. There are other human traits that the children – and the adults they become – will pick up sooner. They laugh, says Curtis. They cry, sing and dance. They count, says Johnson – at least to two and perhaps higher. They don’t recognise the concept of zero, which is a long leap into darkness. Although they might appear feral in some ways to Westerners, they show disgust too, says Joshua Tybur, a social psychologist at VU University in Amsterdam, the Netherlands. Disgust is an important protective mechanism, shielding us from potential dangers in our environment, says Tybur. “Like many other species, we have adaptations for detecting pathogens and motivating pathogen avoidance,” he says. “Disgust is one of those adaptations. I would bet everything I own on these children growing into adults who experience disgust.” These basic emotions and others – anger, joy, sadness, surprise and fear – are hardwired biological features that will emerge whether culture is present or not. >
75,000 years ago
A set of 41 holed shells from Blombos cave are the oldest known jewellery
61,000 years ago
A needle-like bone point from Sibudu cave, South Africa, could be evidence of sewing
43,000 years ago
Bone flute from Divje Babe in Slovenia is the earliest musical instrument
40,000 years ago
Oldest known cave paintings, discovered in Indonesia and Spain
40,000 years ago
Toe bones from China show telltale anatomical signs that their owners wore shoes
28,000 years ago
Impression on fired clay provides evidence of rope-making in Europe
20,000 years ago
The foundations of mud huts around the Sea of Galilee are the oldest known buildings
20,000 years ago
Earliest traces of pottery, from Xianrendong cave in China
11,000 years ago
A site called Göbekli Tepe in Turkey has been proposed as the oldest-known site for organised religion
11,000 years ago
Domesticated cereals and figs in the Fertile Crescent signal the dawn of agriculture and the origin of sedentary living From Top: Marian Vanhaeren & Christopher S. Henshilwood; SASCHA SCHUERMANN/AFP/Getty Images; Science/AAAS
6 June 2015 | NewScientist | 33
Ivan Kashinsky/Panos
become a desired commodity,” says Pettitt. When the women do give birth, their instincts will guide them and the babies will thrive, says Curtis. “Their surprised mothers will figure out what to do to keep them from screaming, because a screaming baby is unrewarding and a happy one is good to be around.” The hard work of looking after vulnerable offspring will probably also produce a sexual division of labour, says Shweder, with males hunting and females taking on lower-risk tasks near their children, such as gathering vegetation.
Belief begins
tURF WARS A never-ending battle is being waged between the tribes. Skirmishes. Ambushes. Raids. Attacks followed by counter-attacks. Battles sometimes last for days. Almost as soon as the babies were placed on the island, they began to form groups, says University of Chicago cultural anthropologist Richard Shweder. “At least two groups and maybe more,” he says. Tribalism is something else that seems to be part of our biological make-up: it can be artificially induced in the lab by something as trivial as giving people different T-shirts, or separating people by eye colour. The formation of groups facilitates cooperation, but also fuels conflict. “People are going to trust members of their ingroup more than they’re going to trust members of outgroups,” says Shweder. Groups won’t share resources. If, for any reason, food or other materials on the island are limited, the tribes will clash over them. Using traditional hunter-gatherers as a template, Johnson predicts the formation of several different tribes. The 100 babies represent a large group, he says, perhaps too large to stay cohesive for very long. “Small-scale hunter-gatherer bands vary in size but are typically a couple of dozen more-or-less related kin,” he says. “This means our island is likely to end up in four or five groups, all in potential competition with each other.” The tribes will fight each other for everything: space, food, tools, dominance. Even within a group, there will be hierarchies and divisions. “They’re going to start stigmatising people who don’t follow the norms,” says Shweder. “They’re going to have 34 | NewScientist | 6 June 2015
banishment.” By banishing members who don’t conform, says Shweder, the islanders begin to build a culture of cooperation, predictability and egalitarianism. Groups will probably also fracture along gender lines, says Shweder. “Males are going to have a very fleeting relationship to the reproductive act,” he says. “It’s going to be: have sex, ejaculate. The females are going to be left with the pregnancy.” Males will probably steal women from each other, and from other groups. “We can expect considerable competition among males for females,” says Johnson. Patriarchy, with males holding primary power and females being exchanged between groups, is a widespread
“It would not take long for the islanders to recognise their own mortality” feature of traditional human societies, says Shweder, especially sedentary ones. It is likely that the islanders will have sex in private. Early on, says Paul Pettitt, an archaeologist at Durham University, UK, the island will be a sexually competitive environment with public displays of sexuality not dissimilar to those seen in chimpanzee troops. But this will change. “As social complexity increases and individuals realise that pair bonding is advantageous – one gender gives birth to children and nurtures them and the other hunts and provides high-quality food – privacy would rapidly
The original population will grow quickly. The tribes will disperse to occupy different parts of the island. The fighting will commence. During periods of hardship, like drought or flood, says, Johnson – again using hunter-gatherers as a model – some of the tribes might come together, forming one larger group, and then splinter again when the hardship passes. But they are never likely to exceed groups of about 150. That is the cognitive limit – known as the Dunbar number – on the number of people with whom any individual can maintain a stable social relationship. Eventually, each tribe on the island will develop its own language. And, between skirmishes and conflicts, the groups will begin to codify their own traditions. From nothing, culture will emerge. The tribes will even begin to form their own religious beliefs, says psychologist Konika Banerjee of Yale University, who wrote a 2013 scientific paper called Would Tarzan believe in God? Conditions for the emergence of religious belief. “Would these babies grow up to have religion?” asks Banerjee. “My guess is that, assuming some degree of typical social cognitive development, we might expect to see certain quasi-supernatural intuitions.” As a part of early development, she says, cognitive biases begin to emerge in the way that children understand the world. “Humans are a prolific creative species,” says Banerjee. “We come up with all sorts of theories and explanations and ideas for making sense of the world.” They may believe that entities such as rocks and trees were designed for a purpose, and that life events have a deeper meaning. In time, the islanders will begin to worship a god, perhaps many. It wouldn’t happen quickly. But it would happen. “Because of our theory of mind, we tend to
Total annihilation
Fadil Aziz/Alcibbum Photography/Corbis
assume that things happen for a reason,” says Johnson. “But the big god idea – that would be hundreds of years down the road.” Eventually, death comes to the island. “Given that the kids would have brains like ours, it would not take long to realise their own mortality,” says Pettitt, who wrote a book called The Paleolithic Origins of Human Burial. “Their imaginations would use religion to overcome the death anxiety and give them reassuring beliefs about the world to come.” Based on what we know about our ancestors’ response to death, it is likely that the islanders will quickly develop funerary rituals, says Pettitt. Deaths provoke a flurry of social activity. As the size of the group grows, the rituals become more elaborate and codified. Each tribe will have its own burial site. They are quiet, unvisited parts of the island. These are the deadlands. “These could be places that are particularly dangerous, where carnivores are numerous, for example,” says Pettitt. “Places where group memory preserves traces of deaths, or simply places that seem a bit spooky and on which the childhood imagination has got to work.” In some cases, the islanders have covered the trees and rocks around the deadlands with colourful handprints, and festooned the tree limbs with jewellery made from abundant objects on the islands – polished shells, a dried and stiffened seahorse. Symbols cover everything. The islanders daub their own bodies with the same symbols that cover the deadlands. Within a few hundred years, the islanders have traditions and cultures. They look like us. Or an earlier version of us, at least.
This is only one of the possible outcomes. Among the multitudinous alternatives, there is another worth mentioning. It is absolute. Two decades later, the only proof that the experiment even took place is the occasional appearance of a small bone on the deserted coastline. Nothing else remains. The forests have fallen silent. The islanders are all dead. Tattersall believes this is the likeliest outcome. “None of them would have survived,” he says. “You cannot think of human beings as independent of their culture and their society. This goes back a long, long way before we were human. It goes back millions and millions of years, back into our primate past, back into our primitive mammal past.” Even the most basic aspects of our cognitive development depend on being raised by linguistic, articulate parents, embedded within a rich and historical culture, says Tattersall. Harvard University cognitive scientist Steven Pinker agrees. “It’s a pathological thought experiment,” he says. Humans need social contact: experiments on chimpanzees by US psychologist Harry Harlow in the 1960s showed that primates, when subjected to total social isolation, exhibit permanent disturbances in simple social behaviour. Research on institutionalised orphans has shown that social interaction with adults and caregivers is a necessary component of normal development. Proximity just to one another will not save the islanders, says Pinker. Abandoned children who endure social deprivation perform worse in IQ tests, and score much lower in tests of cognitive, motor and behavioural development. In other words, even the innate abilities that children possess require a spectrum of different inputs in order to function properly. The same seems to be true for “feral” children who spend all or some of their childhood alone in the wild, but the literature is less clear, with most accounts heavily contested.“It’s like studying how fish swim by taking them out of water and watching them flop on the ground,” says Pinker. There is no way to know the outcome. If Tattersall is right, the island is quiet and pristine once more. But perhaps, in the evening, as the sun dips towards the water, a hoot rises from deep in the forest, rolling above the treetops and then across the island, telling everyone that the hunters are coming home. n
9000 years ago
Traces of rice, hawthorn fruit, grapes and honey on pottery from Jiahu, China, is the earliest evidence of an alcoholic drink
7000 years ago
Oldest securely dated evidence of copper smelting at a site in Serbia
6000 years ago
The first cities begin to spring up in Mesopotamia
5500 years ago
Wheeled vehicles appear near-simultaneously in Mesopotamia, the Caucasus and central Europe
5200 years ago
The oldest writing system we know of is invented by the Sumerians
4100 years ago
The Epic of Gilgamesh is the oldest-known work of literature, although humans surely had an oral storytelling tradition going back hundreds of thousands of years
2700 years ago
Coins invented in the near east, although barter systems and the use of commodity money such as bronze ingots are much older
1200 years ago
Gunpowder invented in China From top: public domain; De Agostini/Getty Images; Classical Numismatic Group, Inc/CC BY-SA 3.0
Christopher Kemp is a writer based in Grand Rapids, Michigan 6 June 2015 | NewScientist | 35
Back to the wild 100 babies. No adults. One island. What would happen if humans grew up without culture, asks Christopher Kemp
30 | NewScientist | 6 June 2015
FRANK SCHERSCHEL/Time & Life/Getty
T
HE island is a strange place. Overgrown, unpredictable, war-torn. For hours during the day, the sun climbs into the sky and it is quiet and peaceful. But later, as the shadows gather in the trees, a volley of hoots erupts from the forest canopy and echoes around the island. Moments later, an answering call bursts from a thickly wooded valley on the other side of the island. A call, and then a response. And then silence. The sound comes again across the tops of the trees. Hooting, and then distant replies. High-pitched and repetitive, the sounds are not words. But they mean something anyway: the hunters are coming home. They emerge one by one from the foliage, stepping out cautiously into a wide and sandy bay. There are five of them, all males. Their bodies are lean and powerful. They carry a few simple tools – hammerstones and sharpened sticks and bones. At the end of the bay, they meet another group of hunters. Gesturing to one another and making primitive sounds, the two groups become one. They make their way to an encampment near the tree line where the women and children wait for them. This is one of the tribes on the island. But the island is not real, and neither are the hunters. There is no encampment or waiting group of women and children. They are all just outcomes of a thought experiment. It goes like this: many years ago, a coldhearted and amoral scientist placed 100 babies on an uninhabited but fertile island, half of them boys, half girls. He provided only the minimum requirements to keep them alive. He left them food and water, being careful not to be seen. He kept them from harm, when possible. For years, the children received none of the trappings of a normal upbringing: no language, no education, no culture. Later, he slowly began feeding and watering them less and less, until eventually he gave them nothing at all. After 20 years, what have they become? How different are they from us? Are they merely hairless apes, or have they retained qualities that make them unquestionably human? Or, to put it more succinctly, when humans grow up without culture, do they invent it anyway?
In the six million plus years since the human lineage split from chimpanzees, evolution has endowed us with many of the attributes that make us who we are: bipedalism, hairlessness, opposable thumbs, extended childhood and a large and complex brain. But these features alone do not make us human. Many of our defining traits – such as language, art, technology, storytelling and cooking – are transmitted culturally. Although products of our biology, they are not fully encoded by genes. Instead, they pass from generation to generation by social learning, evolving as they go. The relative contributions of these two forces – biological and cultural evolution, also known as “nature” and “nurture” – have been debated for centuries. How much of our humanity is hardwired, and how much of it depends on the culture in which we are raised? Are language and religion innate, for example? Are we born violent? Disentangling biology and culture is difficult. They interact and reinforce one another. But there is an experiment that would help tease them apart. It can’t be done in the real world, for ethical reasons. But it is possible to speculate, in the form of a thought experiment. Welcome to the island. >
Creatures of culture Many of the defining traits of our species are the products of cultural as well as biological evolution. Here are some of the important milestones 3.3 million years ago
Earliest stone tools, discovered close to Lake Turkana in Kenya
2 million years ago
Earliest plausible date for primitive language ability
1 million years ago
Ash and burned bone in Wonderwerk cave in South Africa are suggestive of fire and cooking
790,000 years ago
Earliest compelling evidence of controlled use of fire, at Gesher Benot Ya’aqo in Israel
430,000 years ago
Engraving on a shell found in Indonesia could be the earliest art
170,000 years ago
“How much of our humanity is hardwired, and how much depends on culture?”
Genetic evidence from lice suggest that humans were wearing clothes
120,000 years ago
Two skeletons in Israel are the oldest evidence of deliberate burial of the dead
100,000 year ago
Traces of ochre and fat found in two shells in Blombos cave, South Africa, were probably body paint From top: M. Chazan; Wim Lustenhouwer
6 June 2015 | NewScientist | 31
clean slate gesture. I think they would probably use calls. There are obvious reasons that verbalisation is effective: you can call people from afar; you can alert many people at once.” So, the island’s first inhabitants, when they grow up, might well hoot to one another. Their vocalisations could travel across the treetops. Even more interesting, says Senghas, is the linguistic development she expects will take place in subsequent generations. It will happen relatively quickly. Within a few generations, she says, the islanders will be speaking their own unique language. To support her claims, Senghas points to research on song traits in zebra finches, which suggests that the birds’ vocalisation – and probably that of humans too – is genetic in origin, and later shaped by environmental factors. “Only the male sings,” Senghas says, “and the juvenile males learn their song from their fathers.” If juvenile male zebra finches are raised in the absence of adult males, they fail to learn their signature song, but sing nonetheless. “They develop some wacky, spooky song that doesn’t sound like a natural zebra finch song,” says Senghas. “It sounds a lot like white noise.” When those juveniles reach adulthood and mate, they attempt to teach their offspring their strange discordant song. But something incredible happens: “The next generation produces something a little more like natural zebra finch song,” says Senghas. And the generation after that produces something closer again. “It only takes five generations before you’ve got the full-fledged thing.” The first generation of island dwellers might not develop a language, but their brains have
So after 20 years, what have those babies become? We cannot know for sure. But our thought experiment can draw on work from various scientific disciplines, including studies of hunter-gatherers, the evolution of bird song, the development of sign language and research on children raised in orphanages. No one person can supply a complete answer, and many scientists are unwilling even to speculate. Some called the project wild and provocative, others fanciful and incoherent. One potential source dismissed the exercise as “undergrad stoned talk”. Others, though, were enthusiastic to imagine possible outcomes. “My work is in language, so I’ve thought about this a lot,”
says Ann Senghas, a psychologist at Barnard College in New York City who studies sign language in a population of deaf Nicaraguan children. The language emerged spontaneously in a school for the deaf that opened in Managua in 1977, and is now passed down from generation to generation, rapidly evolving like any spoken language. It is linguistic gold dust because the signers have never learned a spoken language or to lip-read. But they invented a language anyway, one that now has the complex linguistic hallmarks common to all others. This, says Senghas, supports the theory that the brain possesses structures that hardwire it for language. In the 1960s, linguist Noam Chomsky proposed that humans are born with a “language acquisition device” – a hypothetical brain module that predisposes us to learn the languages in which we are immersed as babies and toddlers. And it seems that when the language acquisition device never encounters language, it invents one from scratch. So would the first generation of island dwellers speak? “Some people would think because so much of language is innate, that the first cohort would just have it right away, somehow,” Senghas says. “But I don’t think they would.” Although they would, like the Nicaraguan children, invent ways to communicate. “The first generation of those kids would develop certain ways of getting messages across nonverbally,” says Senghas. “I’m betting they would at least come up with the idea of using 32 | NewScientist | 6 June 2015
Tal Paz-Fridman/Plainpicture
“In many ways, the first generation on the island is still distinctly human”
all the necessary structures and neural pathways. Like a juvenile zebra finch building on its father’s atonal song, each successive generation of islanders will possess and develop more language than the last. “I think it would take a couple of generations,” says Senghas, “but not many to develop a language that’s as rich and developed as anything that we have.” This is a crucial breakthrough for the islanders. Once in possession of language, cultural transmission of ideas becomes easier. After they start to speak, says Ian Tattersall, a palaeoanthropologist at the American Museum of Natural History, they begin naming things. Eventually, the islanders begin to do something all human cultures do, and which probably emerged not long after sophisticated language did, perhaps 200,000 years ago: they name each other. In many ways, our first generation is still resolutely human too. Even in the absence of culture, millions of years of biological evolution has endowed them with a complex brain and many distinctly human traits. They do not become mere apes overnight. In fact, says Dominic Johnson at the University of Oxford, who uses evolutionary theory to study conflict and cooperation, if a Martian zoologist visited Earth to study its inhabitants, the islanders would provide better and more instructive examples of Homo sapiens than we do. “Our physiology and behaviour were designed for life in the wilderness with scarce resources and a few dozen or so other people,”
Roy Toft/National Geographic/Getty
he says. “That’s our natural habitat. We are certainly not designed for life in modern megacities with fast food on every corner.” In time, says Johnson, the islanders might begin to resemble modern hunter-gatherer groups. “Hunter-gatherers provide a window into our human nature and the things that emerge spontaneously in human organisations when they’re not surrounded by modern culture,” he says. For instance, the islanders are likely to invent tools and use them for many tasks. In the beginning, the tools are simple, developed by trial and error. Swung with determination, a heavy rock is a tool. A broken rock, with a sharp unfinished edge for cutting, is a better tool.
Tribe and error The island ecology will play its part too, says Johnson. Tribal groups in New Guinea and Tibet are vastly different to one another, their lives shaped fundamentally by their surroundings. For tools, the children can use only what they find on the island. Perhaps they will learn to fashion fish hooks from bone. They can harvest and eat only what grows there, and hunt only the animals endemic to the island and its waters. In time, by trial and error – and by making costly mistakes – they learn what is good and safe to eat, and they pass that knowledge on to each other and to their offspring. They will be willing experimenters, and even more willing learners. Humans seem to have an evolved tendency for individual
learning and copying, especially of successful individuals. In this way, culture gradually improves and spreads, with new discoveries building on previous ones. Unlike groups that live in cold or mountainous places, the islanders go naked: they have no need to invent clothes. Whatever their environment, the islanders will adapt to it, says Val Curtis, a behavioural scientist at the London School of Hygiene and Tropical Medicine and co-author of Gaining Control: How human behavior evolved. “Brains are learning machines,” says Curtis. “Our minds come pre-equipped with structure that allows us to learn to behave adaptively.” For example, if the children have to crack a nut, they intuitively understand that a rock will allow them to do it quickly. “I predict that our abandoned kids will soon have their environment mapped and will figure out where to find or make shelters, beds and tools,” says Curtis. Each tool they develop will be a little more sophisticated than the previous one. “But you know what?” says Senghas. “It’ll be a long time before they figure out the wheel.” The mastery of fire and the development of simple machines like ramps and pulleys will take thousands of years, says Senghas – the same amount of time as it took humans to invent them the first time. “Generating things like levers and wheels and fire and cooking involved work and experimentation, and getting so far and then being able to pass that down culturally to the next generation,” she says. There are other human traits that the children – and the adults they become – will pick up sooner. They laugh, says Curtis. They cry, sing and dance. They count, says Johnson – at least to two and perhaps higher. They don’t recognise the concept of zero, which is a long leap into darkness. Although they might appear feral in some ways to Westerners, they show disgust too, says Joshua Tybur, a social psychologist at VU University in Amsterdam, the Netherlands. Disgust is an important protective mechanism, shielding us from potential dangers in our environment, says Tybur. “Like many other species, we have adaptations for detecting pathogens and motivating pathogen avoidance,” he says. “Disgust is one of those adaptations. I would bet everything I own on these children growing into adults who experience disgust.” These basic emotions and others – anger, joy, sadness, surprise and fear – are hardwired biological features that will emerge whether culture is present or not. >
75,000 years ago
A set of 41 holed shells from Blombos cave are the oldest known jewellery
61,000 years ago
A needle-like bone point from Sibudu cave, South Africa, could be evidence of sewing
43,000 years ago
Bone flute from Divje Babe in Slovenia is the earliest musical instrument
40,000 years ago
Oldest known cave paintings, discovered in Indonesia and Spain
40,000 years ago
Toe bones from China show telltale anatomical signs that their owners wore shoes
28,000 years ago
Impression on fired clay provides evidence of rope-making in Europe
20,000 years ago
The foundations of mud huts around the Sea of Galilee are the oldest known buildings
20,000 years ago
Earliest traces of pottery, from Xianrendong cave in China
11,000 years ago
A site called Göbekli Tepe in Turkey has been proposed as the oldest-known site for organised religion
11,000 years ago
Domesticated cereals and figs in the Fertile Crescent signal the dawn of agriculture and the origin of sedentary living From Top: Marian Vanhaeren & Christopher S. Henshilwood; SASCHA SCHUERMANN/AFP/Getty Images; Science/AAAS
6 June 2015 | NewScientist | 33
Ivan Kashinsky/Panos
become a desired commodity,” says Pettitt. When the women do give birth, their instincts will guide them and the babies will thrive, says Curtis. “Their surprised mothers will figure out what to do to keep them from screaming, because a screaming baby is unrewarding and a happy one is good to be around.” The hard work of looking after vulnerable offspring will probably also produce a sexual division of labour, says Shweder, with males hunting and females taking on lower-risk tasks near their children, such as gathering vegetation.
Belief begins
tURF WARS A never-ending battle is being waged between the tribes. Skirmishes. Ambushes. Raids. Attacks followed by counter-attacks. Battles sometimes last for days. Almost as soon as the babies were placed on the island, they began to form groups, says University of Chicago cultural anthropologist Richard Shweder. “At least two groups and maybe more,” he says. Tribalism is something else that seems to be part of our biological make-up: it can be artificially induced in the lab by something as trivial as giving people different T-shirts, or separating people by eye colour. The formation of groups facilitates cooperation, but also fuels conflict. “People are going to trust members of their ingroup more than they’re going to trust members of outgroups,” says Shweder. Groups won’t share resources. If, for any reason, food or other materials on the island are limited, the tribes will clash over them. Using traditional hunter-gatherers as a template, Johnson predicts the formation of several different tribes. The 100 babies represent a large group, he says, perhaps too large to stay cohesive for very long. “Small-scale hunter-gatherer bands vary in size but are typically a couple of dozen more-or-less related kin,” he says. “This means our island is likely to end up in four or five groups, all in potential competition with each other.” The tribes will fight each other for everything: space, food, tools, dominance. Even within a group, there will be hierarchies and divisions. “They’re going to start stigmatising people who don’t follow the norms,” says Shweder. “They’re going to have 34 | NewScientist | 6 June 2015
banishment.” By banishing members who don’t conform, says Shweder, the islanders begin to build a culture of cooperation, predictability and egalitarianism. Groups will probably also fracture along gender lines, says Shweder. “Males are going to have a very fleeting relationship to the reproductive act,” he says. “It’s going to be: have sex, ejaculate. The females are going to be left with the pregnancy.” Males will probably steal women from each other, and from other groups. “We can expect considerable competition among males for females,” says Johnson. Patriarchy, with males holding primary power and females being exchanged between groups, is a widespread
“It would not take long for the islanders to recognise their own mortality” feature of traditional human societies, says Shweder, especially sedentary ones. It is likely that the islanders will have sex in private. Early on, says Paul Pettitt, an archaeologist at Durham University, UK, the island will be a sexually competitive environment with public displays of sexuality not dissimilar to those seen in chimpanzee troops. But this will change. “As social complexity increases and individuals realise that pair bonding is advantageous – one gender gives birth to children and nurtures them and the other hunts and provides high-quality food – privacy would rapidly
The original population will grow quickly. The tribes will disperse to occupy different parts of the island. The fighting will commence. During periods of hardship, like drought or flood, says, Johnson – again using hunter-gatherers as a model – some of the tribes might come together, forming one larger group, and then splinter again when the hardship passes. But they are never likely to exceed groups of about 150. That is the cognitive limit – known as the Dunbar number – on the number of people with whom any individual can maintain a stable social relationship. Eventually, each tribe on the island will develop its own language. And, between skirmishes and conflicts, the groups will begin to codify their own traditions. From nothing, culture will emerge. The tribes will even begin to form their own religious beliefs, says psychologist Konika Banerjee of Yale University, who wrote a 2013 scientific paper called Would Tarzan believe in God? Conditions for the emergence of religious belief. “Would these babies grow up to have religion?” asks Banerjee. “My guess is that, assuming some degree of typical social cognitive development, we might expect to see certain quasi-supernatural intuitions.” As a part of early development, she says, cognitive biases begin to emerge in the way that children understand the world. “Humans are a prolific creative species,” says Banerjee. “We come up with all sorts of theories and explanations and ideas for making sense of the world.” They may believe that entities such as rocks and trees were designed for a purpose, and that life events have a deeper meaning. In time, the islanders will begin to worship a god, perhaps many. It wouldn’t happen quickly. But it would happen. “Because of our theory of mind, we tend to
Total annihilation
Fadil Aziz/Alcibbum Photography/Corbis
assume that things happen for a reason,” says Johnson. “But the big god idea – that would be hundreds of years down the road.” Eventually, death comes to the island. “Given that the kids would have brains like ours, it would not take long to realise their own mortality,” says Pettitt, who wrote a book called The Paleolithic Origins of Human Burial. “Their imaginations would use religion to overcome the death anxiety and give them reassuring beliefs about the world to come.” Based on what we know about our ancestors’ response to death, it is likely that the islanders will quickly develop funerary rituals, says Pettitt. Deaths provoke a flurry of social activity. As the size of the group grows, the rituals become more elaborate and codified. Each tribe will have its own burial site. They are quiet, unvisited parts of the island. These are the deadlands. “These could be places that are particularly dangerous, where carnivores are numerous, for example,” says Pettitt. “Places where group memory preserves traces of deaths, or simply places that seem a bit spooky and on which the childhood imagination has got to work.” In some cases, the islanders have covered the trees and rocks around the deadlands with colourful handprints, and festooned the tree limbs with jewellery made from abundant objects on the islands – polished shells, a dried and stiffened seahorse. Symbols cover everything. The islanders daub their own bodies with the same symbols that cover the deadlands. Within a few hundred years, the islanders have traditions and cultures. They look like us. Or an earlier version of us, at least.
This is only one of the possible outcomes. Among the multitudinous alternatives, there is another worth mentioning. It is absolute. Two decades later, the only proof that the experiment even took place is the occasional appearance of a small bone on the deserted coastline. Nothing else remains. The forests have fallen silent. The islanders are all dead. Tattersall believes this is the likeliest outcome. “None of them would have survived,” he says. “You cannot think of human beings as independent of their culture and their society. This goes back a long, long way before we were human. It goes back millions and millions of years, back into our primate past, back into our primitive mammal past.” Even the most basic aspects of our cognitive development depend on being raised by linguistic, articulate parents, embedded within a rich and historical culture, says Tattersall. Harvard University cognitive scientist Steven Pinker agrees. “It’s a pathological thought experiment,” he says. Humans need social contact: experiments on chimpanzees by US psychologist Harry Harlow in the 1960s showed that primates, when subjected to total social isolation, exhibit permanent disturbances in simple social behaviour. Research on institutionalised orphans has shown that social interaction with adults and caregivers is a necessary component of normal development. Proximity just to one another will not save the islanders, says Pinker. Abandoned children who endure social deprivation perform worse in IQ tests, and score much lower in tests of cognitive, motor and behavioural development. In other words, even the innate abilities that children possess require a spectrum of different inputs in order to function properly. The same seems to be true for “feral” children who spend all or some of their childhood alone in the wild, but the literature is less clear, with most accounts heavily contested.“It’s like studying how fish swim by taking them out of water and watching them flop on the ground,” says Pinker. There is no way to know the outcome. If Tattersall is right, the island is quiet and pristine once more. But perhaps, in the evening, as the sun dips towards the water, a hoot rises from deep in the forest, rolling above the treetops and then across the island, telling everyone that the hunters are coming home. n
9000 years ago
Traces of rice, hawthorn fruit, grapes and honey on pottery from Jiahu, China, is the earliest evidence of an alcoholic drink
7000 years ago
Oldest securely dated evidence of copper smelting at a site in Serbia
6000 years ago
The first cities begin to spring up in Mesopotamia
5500 years ago
Wheeled vehicles appear near-simultaneously in Mesopotamia, the Caucasus and central Europe
5200 years ago
The oldest writing system we know of is invented by the Sumerians
4100 years ago
The Epic of Gilgamesh is the oldest-known work of literature, although humans surely had an oral storytelling tradition going back hundreds of thousands of years
2700 years ago
Coins invented in the near east, although barter systems and the use of commodity money such as bronze ingots are much older
1200 years ago
Gunpowder invented in China From top: public domain; De Agostini/Getty Images; Classical Numismatic Group, Inc/CC BY-SA 3.0
Christopher Kemp is a writer based in Grand Rapids, Michigan 6 June 2015 | NewScientist | 35