Six 'uniquely' human traits now found in animals
So you think humans are unique?
21 May 2008
From New Scientist Print Edition.
THERE was a time when we thought humans were special in so many ways. Now we know better. We are not the only species that feels emotions, empathises with others or abides by a moral code. Neither are we the only ones with personalities, cultures and the ability to design and use tools. Yet we have steadfastly clung to the notion that one attribute, at least, makes us unique: we alone have the capacity for language.
Alas, it turns out we are not so special in this respect either. Key to the revolutionary reassessment of our talent for communication is the way we think about language itself. Where once it was seen as a monolith, a discrete and singular entity, today scientists find it is more productive to think of language as a suite of abilities. Viewed this way, it becomes apparent that the component parts of language - everything from gesticulation and babbling to meaning and syntax - are not as unique as the whole. In fact, a boom in research into animal cognition and communication has gradually picked off most items on the list one by one.
Take gesture, arguably the starting point for language. Until recently it was considered uniquely human - but not any more. Mike Tomasello of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and others have compiled a list of gestures observed in monkeys, gibbons, gorillas, chimpanzees, bonobos and orang-utans, which reveals that gesticulation plays a large role in their communication (Gesture, vol 5, p 39). Ape gestures can involve touch, vocalising or eye movement, and individuals wait until they have another ape's attention before making visual or auditory gestures. If their gestures go unacknowledged, they will often repeat them or touch the recipient.
[The article below is edited for brevity. - ag]
Six 'uniquely' human traits now found in animals
17:11 22 May 2008
NewScientist.com news service
Art, theatre, literature, music, religion, architecture and cuisine - these are the things we generally associate with culture. Clearly no other animal has anything approaching this level of cultural sophistication. But culture at its core is simply the sum of a particular group's characteristic ways of living, learned from one another and passed down the generations, and other primate species undoubtedly have practices that are unique to groups, such as a certain way of greeting each other or obtaining food.
Even more convincing examples of animal cultures are found in cetaceans. Killer whales, for example, fall into two distinct groups, residents and transients. Although both live in the same waters and interbreed, they have very different social structures and lifestyles, distinct ways of communicating, different tastes in food and characteristic hunting techniques - all of which parents teach to offspring.
Hal Whitehead, Dalhousie University writes:
"Since our 2001 review, people have often considered culture as a potential explanation of the behavioural patterns that have turned up in their studies of whales and dolphins.
"Our own work has concentrated on the non-vocal forms of sperm-whale culture. The different cultural clans of sperm whales, although in basically the same areas, use these waters very differently, and are affected very differently by El Niño events. They also have different reproductive rates.
"In sperm whales, and likely other whales and dolphins, culture has the potential to affect population biology, and so issues as diverse as genetic evolution and the impacts of global warming on the species."
2. Mind reading
Perhaps the surest sign that an individual has insight into the mind of another is the ability to deceive. To outwit someone you must understand their desires, intentions and motives - exactly the same ability that underpins the "theory of mind". This ability to attribute mental states to others was once thought unique to humans, emerging suddenly around the fifth year of life. But the discovery that babies are capable of deception led experts to conclude that "mind-reading" skills develop gradually, and fuelled debate about whether they might be present in other primates.
Experiments in the 1990s indicated that great apes and some monkeys do understand deception, but that their understanding of the minds of others is probably implicit rather than explicit as it is in adult humans.
3. Tool use
Some chimps use rocks to crack nuts, others fish for termites with blades of grass and a gorilla has been seen gauging the depth of water with the equivalent of a dipstick, but no animal wields tools with quite the alacrity of the New Caledonian crow. To extract tasty insects from crevices, they craft a selection of hooks and long, barbed tapers called stepped-cut tools, made by intricately cutting a pandanus leaf with their beaks. What's more, experiments in the lab suggest that they understand the function of tools and deploy creativity and planning to construct them.
Nobody is suggesting that toolmaking has common origins in humans and crows, but there is a remarkable similarity in the ways in which their respective brains work. Both are highly lateralised, revealed in the observation that most crows are right-beaked - cutting pandanus leaves using the right side of their beaks. New Caledonian crows may force us to reassess the mental abilities of our first toolmaking ancestors.
A classic study in 1964 found that hungry rhesus monkeys would not take food they had been offered if doing so meant that another monkey received an electric shock. The same is true of rats. Does this indicate nascent morality? For decades, we have preferred to find alternative explanations, but recently ethologist Marc Bekoff from the University of Colorado at Boulder has championed the view that humans are not the only moral species. He argues that morality is common in social mammals, and that during play they learn the rights and wrongs of social interaction, the "moral norms that can then be extended to other situations such as sharing food, defending resources, grooming and giving care".
Marc Bekoff, University of Colorado, writes:
"Work published this year showed that animals are able to make social evaluations and these assessments are foundational for moral behaviour in animals other than humans. Francys Subiaul of the George Washington University and his colleagues showed that captive chimpanzees are able to make judgments about the reputation of unfamiliar humans by observing their behaviour - whether they were generous or stingy in giving food to other humans. The ability to make character judgments is just what we would expect to find in a species in which fairness and cooperation are important in interactions among group members (Animal Cognition, DOI: 10.1007/s10071-008-0151-6)."
Emotions allow us to bond with others, regulate our social interactions and make it possible to behave flexibly in different situations. We are not the only animals that need to do these things, so why should we be the only ones with emotions? There are many examples of apparent emotional behaviour in other animals.
Elephants caring for a crippled herd member seem to show empathy. A funeral ritual performed by magpies suggests grief. Was it spite that led a male baboon called Nick to take revenge on a rival by urinating on her? Divers who freed a humpback whale caught in a crab line describe its reaction as one of gratitude. Then there's the excited dance chimps perform when faced with a waterfall - it looks distinctly awe-inspired. These days, few doubt that animals have emotions, but whether they feel these consciously, as we do, is open to debate.
It's no surprise that animals that live under constant threat from predators are extra-cautious, while those that face fewer risks appear to be more reckless. After all, such successful survival strategies would evolve by natural selection. But the discovery that individuals of the same species, living under the same conditions, vary in their degree of boldness or caution is more remarkable. In humans we would refer to such differences as personality traits.
From cowardly spiders and reckless salamanders to aggressive songbirds and fearless fish, we are finding that many animals are not as characterless as we might expect. What's more, work with animals has led to the idea that personality traits evolve to help individuals survive in a wider variety of ecological niches, and this is influencing the way psychologists think about human personality.