My latest Mind and Matter column for the Wall
Identifying unique features of human beings is a cottage
industry in psychology. In his book "Stumbling on Happiness," the Harvard
psychologist Daniel Gilbert jokes that every member of his
profession lives under the obligation at some time in his career to
complete a sentence which begins: "The human being is the only
animal that..." Those who have completed the sentence with phrases
like "makes tools," "is conscious" or "can imitate" have generally
now conceded that some other animals also have these traits.
Plenty of human uniqueness remains. After all, uniqueness is
everywhere in the biological world: Elephants and worms also have
unique features. As fast as one scientist demotes human beings from
being unique in one trait, another scientist comes up with a new
unique trait: grandparental care, for instance, or extra spines on
the pyramidal cells of our prefrontal cortex.
In such debates, scientists must sail between the Scylla of
human hubris (for example, saying that a dreaming dog is not
equivalent to a dreaming person) and the Charybdis of mistakenly
attributing human traits to animals. A case of the latter problem
was pointed out this month in a paper by Marco Vasconcelos and Alex Kacelnik
of Oxford University writing with Karen Hollis and Elise Nowbahari
of the University of Paris.
It concerned two experiments. In one, scientists at the University of Chicago
put two rats in an arena, one held by a restrainer, the other free.
They found that the free rat learned to "intentionally and quickly
open the restrainer and free the cagemate." They interpreted this
result as "providing strong evidence for biological roots of
empathically motivated helping behavior."
In the other case, Drs. Hollis and Nowbahari
themselves did a very similar experiment with ants. They found that
ants were prepared to rescue fellow ants held in a nylon snare and
showing obvious distress. Just like the rats, the hero ants would
chew at the restraints (though not if the victims were anesthetized
or from different colonies or species). Happy to describe such
behavior as "pro-social," they did not go so far as to attribute
empathy to the ants. There was no reason to think that the hero
ants were motivated by a wish to alleviate the suffering of the
victims. More likely, they possessed a self-interested instinct to
help get a co-worker back to work.
Ant biting the nylon snare holding a nestmate down
In his 1759 book the "Theory of the Moral Sentiments,"
philosopher Adam Smith argued that empathy (he called it sympathy)
was motivated by the capacity to imagine being another person.
"When I condole with you for the loss of your only son, in order to
enter into your grief, I do not consider what I, a person of such a
character and profession, should suffer, if I had a son, and if
that son was unfortunately to die; but I consider what I should
suffer if I was really you; and I not only change circumstances,
but I change persons and characters. My grief, therefore, is
entirely upon your account, and not in the least upon my own. It is
not, therefore, in the least selfish." (Pt 7, section 3, chap 1,
Either we must conclude that even ants are capable of such
empathic suffering, which seems absurd, or we must view the rat
experiments as proving nothing about psychological motivation,
leaving human beings on a pedestal. In the same way that evolution
by natural selection can produce purposeful designs without an
intelligent designer to prefigure the purpose, so animals can show
behavior that evolved to be purposeful but is not psychologically
motivated. The rats may decide to free their fellow rats because
they're descended from rats that helped relatives and thus allowed
their genes to thrive, not because they feel their fellows'
And human beings? Can we be so sure it is fellow-feeling rather
than instinct that drives us to our virtuous as well as our vicious