When Robert Sapolsky and Lisa Share first started to study a particular troop of baboons in Kenya’s Masai Mara in the 1970s it had the usual squabbling mixture of aggressive, high-ranking males, pacific, low-ranking ones, females and infants.
In the 1980s the high-status males of the troop started to scavenge at a nearby rubbish dump; in 1983 tuberculosis, probably from infected meat at the dump, killed every one of them.
A decade later, the behaviour of the troop had changed out of all recognition.
Gone was the bullying by high-ranking males; there was more grooming and lower levels of stress hormones. This was not because only the low-ranking, pacific males had been spared: many new males had joined the troop.
But they seemed to have learned from the survivors a more placid behaviour. As Dr Sapolsky and Dr Share put it, a “pacific culture” had emerged.
There is a great deal more to learn about animal minds.
In the Middle
Grammatical language can pretty thoroughly be ruled out; learned toolmaking for some species is now unquestionable: but many conclusions are in the middle, neither definitively in nor out.
Whether you accept them depends partly on the standard of evidence required.
If the question of animal empathy were being tested in a criminal court, demanding proof beyond reasonable doubt, you might hesitate to find that it exists.
If the trial were a civil one, requiring a preponderance of evidence, you would probably conclude that animals had empathy.
Using that standard, one can hazard three conclusions.
First, various animals do have minds. The physiological evidence of brain functions, their communications and the versatility of their responses to their environments all strongly support the idea.
Primates, corvids and cetaceans also have attributes of culture, if not language or organised religion (though Jane Goodall, a noted zoologist, sees chimps as expressing a pantheistic pleasure in nature).
Next, animals’ abilities are patchy compared with those of humans. Dogs can learn words but do not recognise their reflections. Clark’s nutcracker, a member of the crow family, buries up to 100,000 seeds in a season and remembers where it put them months later—but does not make tools, as other corvids do.
These specific, focused abilities fit with some modern thinking about human minds, which sees them less as engines of pure reason that can be applied in much the same way to all aspects of life as bundles of subroutines for specific tasks.
On this analysis a human mind might be a Swiss army knife, an animal mind a corkscrew or pair of tweezers.
This suggests a corollary—that there will be some dimensions in which animal minds exceed humans.
Take the example of Ayumu, a young chimpanzee who lives at the Primate Research Institute of the University of Kyoto. Researchers have been teaching Ayumu a memory task in which a random pattern of numbers appears fleetingly on a touchscreen before being covered by electronic squares.
Ayumu has to touch the on-screen squares in the same order as the numbers hidden beneath them. Humans get this test right most of the time if there are five numbers and 500 milliseconds or so in which to study them.
With nine numbers, or less time, the human success rate declines sharply. Show Ayumu nine numbers flashed up for just 60 milliseconds and he will nonchalantly tap out the numbers in the right order with his knuckles.
There are humans with so called eidetic, or flash, memories who can do something similar—for chimps, though, this seems to be the norm.
Is it an attribute that chimps have evolved since their last common ancestor with humans for some reason—or one that humans have lost over the same period of time?
More deeply, how might it change what it is for a chimp to have a mind?
How different is having minds in a society where everyone remembers such things?
Tell me how I feel
Animals might well think in ways that humans cannot yet decipher because they are too different from the ways humans think—adapted to sensory and mental realms utterly unlike that of the human, perhaps realms that have not spurred a need for language.
There is, for example, no doubt that octopuses are intelligent; they are ferociously good problem solvers. But can scientists begin to imagine how an octopus might think and feel?
All that said, the third general truth seems to be that there is a link between mind and society which animals display.
The wild animals with the highest levels of cognition (primates, cetaceans, elephants, parrots) are, like people, long-lived species that live in complex societies, in which knowledge, social interaction and communication are at a premium.
It seems reasonable to speculate that their minds—like human ones—may well have evolved in response to their social environment. And this may be what allows minds on the two sides of the inter-species gulf to bridge it.