Blog

Archive for February 2008

Elephants in the Field

For three months, I’ve been spending a lot of time away from our
lab’s two focal species, chimpanzees and capuchins, in favor of a
slightly larger, yet still highly intelligent mammal, the elephant.
Yesterday, I sat in a field in a northern Thai jungle watching a
group of semi-captive Asian elephants ever-so-slowly grazing on a
large plot of jungle grass. As is often the case, one of the young
infants in a family group of 5-6 individuals wandered away from her
family and over to one of the males in musth – a period during which
bull elephants are often aggressive and “hormonal,” and playfully
began to tease him, chirping – repetitive, often high-pitched sounds
that elephants make for a variety of reasons including excitement -
and backing in and out of the bull’s trunk range. All of a sudden,
for no apparent reason (at least not for one my eyes or ears could
pick up), she let out a loud, infant-specific squeal. Three of the
four females standing on the other side of the field immediately
responded, and with their ears out, tails raised and legs in a full-
on sprint, each let out loud trumpet bursts before they reached the
“lost” infant. They immediately circled around her, all facing
outward while they kept her enclosed in the middle, touching her with
their trunks and continuously rumbling, while obviously paying
careful attention to the surrounding environment. A few minutes
later, the fourth individual, slowly walked over to the infant,
touched her face, and resumed her morning grazing.

Such infant-centric behavior is not uncommon in elephants, and
African elephant researchers J. Poole, C. Moss, K. Payne and I.
Douglas-Hamilton have all described it in their own investigations of
elephant behavior. But something sticks out here – the fourth, less-
interested elephant is in fact the infant’s mother. The other three
elephants are the infant’s “aunties,” and although they all share a
place in what appears to be a cohesive family unit, they are all
completely unrelated to the infant, and each other. The complexity
of such cooperative and seemingly empathic behavior is one of the
many areas on which I hope to focus my research here. If you’d like
to find out more, feel free to contact me at jplotni@emory.edu.

– Josh Plotnik

Fair Comparisons Between Children & Apes

The journal of Science in February, 2008, finally published a letter submitted to them mid September, 2007, by Frans BM de Waal, Christophe Boesch, Victoria Horner, and Andrew Whiten, under the heading “Comparing social skills of children and apes” (Science 319: 569). Below, we reproduce the original, which is slightly longer than the published version.

A recent study in Science by Esther Herrmann et al. (7 September 2007, p. 1360) claims equivalence in technical skills between apes – chimpanzees and orangutans – and two-year-old human children, but inferior social skills in the apes. These results are taken as support for a “cultural intelligence hypothesis.”

The study features an impressive battery of tests, seemingly administered in the same format to apes and children. It has been pointed out before, however, that the easiest way to standardize conditions – by having a human experimenter provide the social cues – introduces handicaps for the apes. When the experimenter is human for all subjects, only the apes are dealing with a species other than their own. This may not be as relevant for physical or technical problems, which focus on inanimate objects, but one expects this to matter for social tasks which rely crucially on the relation between experimenter and subject. The reported findings are consistent with the apes being handicapped specifically in the social domain.

The differences between the set ups for children and apes in this study appear multifold. Human children sit on or next to their parent (introducing potential “Clever Hans” effects), are talked to, are used to dealing with human strangers, and are tested by a member of their own species. The apes are alone, observe the task from behind a barrier, receive no verbal instructions, and are tested by a species not their own. We are not suggesting that human experimenters should never be used, but that the social skills which matter most for apes, especially as they relate to culture, are those shown with conspecific models.

Study set-ups for children (above) and chimpanzees (from Hermann et al 2007, online material)

In fact, evidence for ape-to-ape social learning is plentiful. Studies of wild chimpanzees in Africa have documented an impressive array of group-specific traditions attributed to social learning. Apes tested with a human model whom they have grown close to, or with a familiar member of their group, have recently demonstrated social learning that has extended to high-fidelity cultural transmission within and between groups. For the latest studies on this, explore our cultural learning website.

These findings conflict with the results as well as the central thesis of Herrmann et al. Ignoring this literature, as they have chosen to do, can only lead to a fragmented literature, a situation exacerbated by the fact that a “cultural intelligence hypothesis” already exists, formulated to explain the cultural complexity of both humans and the great apes. Mysteriously, given the title of Herrmann et al.’s article, this earlier usage of the term also remains uncited. We strongly urge testing of cognition in ecologically valid settings, such as testing social skills with conspecifics. The problem of the human model would be even more severe in relation to Herrmann et al.’s proposal to extend their test battery to more distantly related species.

As a thought experiment, ask what would happen if we trained apes to apply tests to human children so that these, too, faced a species-barrier. We doubt that this would do the children’s performance any good!

–Victoria Horner

For further reading on the controversy of how to fairly compare apes with children, see the following two publications:

* Chapter 6 of de Waal, F. B. M. 2001. The Ape and the Sushi Master. New York: Basic Books.
* Boesch, C. 2007. What Makes Us Human? The Challenge of Cognitive Cross-Species Comparison. J. Comp. Psychol. 121: 227-240.

 

Top