Sunday, October 13, 2013
The next time you need to show an elephant where something is, just point. Chances are he’ll understand what you mean.
New research shows elephants spontaneously understand the communicative intent of human pointing and can use it as a cue to find food. Richard Byrne and Anna Smet of the University of St. Andrews tested 11 African elephants on what’s known as the object-choice task. In this task, a food reward is hidden in one of several containers and the experimenter signals which one by pointing to it.
People understand pointing, even as young children. But the track record of other animals on the object-choice task is mixed. Domesticated animals, such as dogs, cats, and horses, tend to perform better than wild ones. Even our closest relative, the chimpanzee, typically struggles to understand pointing when it’s used by human caretakers.
What’s so remarkable about the elephants’ success on the object-choice task is that they did it spontaneously. Byrne says that in studies of other species, the animals have had the opportunity to learn the task. This is usually during the experiment itself, which consists of a prolonged series of tests over which the animals come to realize they will get rewarded with food if they follow the line of the human’s pointing.
But the elephants performed as well on the first trial as on later tests and showed no signs of learning over the course of the experiments. The elephants Byrne and Smet tested are used to take tourists on elephant-back rides in southern Africa. They were trained to follow vocal commands only, never gestures. Smet recorded the behavior of the elephants’ handlers over several months and found they never pointed their arms for the elephants. What’s more, the elephants’ ability to understand human pointing did not vary with how long they had lived with people, nor with whether they were captive-born or wild-born. “If they have learned to follow pointing from their past experiences, it’s mystery when and how,” Byrne says. “Rather, it seems they do it naturally.”
In the experiment, Byrne and Smet varied several parameters that often affect children’s and animals’ performance on the task: whether the pointing arm was nearest the correct choice or not; whether the pointer’s arm crossed the body or was always on the side of what was pointed at; and whether the arm broke the silhouette from the elephant’s viewpoint or not. None of these made any difference. Even when the experimenter stood closer to the wrong location than the correct location, the elephants performed a little worse but still mostly responded to where her arm was pointing.
The only condition that truly stymied the elephants was when the experimenter simply looked at the correct location without pointing. Byrne says that elephant eyesight is poor compared to our own, and researchers who work with elephants have commented on how bad they are at identifying things by sight. “It would perhaps have been surprising if they had spontaneously responded to the rather subtle movements of a small primate’s head!” Byrne says.
Elephants are only distantly related to humans, which means that the ability to understand pointing likely evolved separately in both species, and not in a shared ancestor. But why would elephants attend to and understand pointing? One thing elephants do share with humans is that they live in a complex and extensive social network in which cooperation and communication with others play a critical role. Byrne and Smet speculate that pointing relates to something elephants do naturally in their society. “The most likely possibility is that they regularly interpret trunk gestures as pointing to places in space,” Byrne says. Elephants do make many prominent trunk gestures, and Byrne and Smet are currently trying to determine if those motions act as “points” in elephant society.
Smet, Anna F. and Byrne, Richard W. (2013). African Elephants Can Use Human Pointing Cues to Find Hidden Food. Current Biology
Posted by Wade G. Burck