Why Do We Point? Scientists Say Our Fingers Aren't "Arrows"

Here's why the "arrow hypothesis" doesn't hold up.

spider-man point

Pointing is the very first gesture babies use to refer to the objects around them. This is true across human societies: Across the planet, people begin pointing at about nine to 14 months and continue for the rest of their lives. It’s easy to assume that we point in order to call attention to things, but as scientists argue in Science Advances, the real reason we do so has nothing to do with using our finger as an arrow.

Scientists had previously argued that pointing is important because it lays the foundation for language acquisition. However, scientists have never been sure why we rely on this specific movement. Why point when you could, say, thrust your head or shake your elbow?

In the study released Wednesday, researchers from the Jean Nicod Institute in Paris argue that the reason we point comes down to the original intention behind the action. Pointing, they posit, begins in infancy as an attempt to touch an object. This study is the first to provide experimental results to back up that claim.

“Pointing is the first thing that infants do to coordinate attention with adults and the coordination of attention of adults is a crucial elements in all sorts of things like language, cooperation, and social interaction in general,” first author Cathal O’Madagain, Ph.D. tells Inverse. “Nevertheless, there was no convincing account available of why infants begin to point — which they do spontaneously all over the world at around the same age.”

Studies have shown that toddlers who point more become kindergarteners with better vocabularies. 

O’Madagain and co-author Brent Strickland, Ph.D. were sitting at the Cafe Waikiki in Paris when they started thinking about why they gestured the way they do. They realized that when they pointed at things, they didn’t look like they were directing their fingers as arrows but more so like they were poking at the object in their visual field. This led them to consider that pointing could have originated in touch.

Collaborating with Gregor Kachel, Ph.D. a researcher at the Potsdam University of Applied Sciences, they set up three study trials designed as games that involved pointing.

The first experiment was designed to see whether people really did use their fingers during pointing like an arrow. Participants representing a wide age range — 18 months, three years, six years, and adults — were asked to point at different objects; cups if they were adult; a puppet if they were babies. The researchers then measured the angles between the pointed fingers and the objects and found that the tip of the finger consistently looked like it could make contact with the object if its trajectory was traced with a straight line.

The second experiment was based on the prediction that individuals who were actually trying to touch the object would rotate their wrists when they pointed — much like they would do if they were trying to actually make contact. Here too, they observed their predicted effect consistently and across age groups. People reliably pointed to targets at odd angles, demonstrating the “strength of the impulse to orient the hand as though attempting to touch the target.”

The final experiment was designed to see how the touch hypothesis influenced how people interpret pointing done by another person. Participants were shown images of a face and ambiguous pointing gestures and were asked to decide whether the gestures conveyed an arrow or an intention to touch. Here’s an example:

pointing experiment
One the left, the point is designed to be an arrow. On the right, it is designed to support the "touch hypothesis." 

As predicted, the six-year olds and the adults accurately labeled the images and could also tell which of the cups was the focus of the image based on the angle and location of the point. Babies, however, were more likely to choose the cup that the person in the image was looking at, regardless of what the finger was doing.

This, the team argues, suggested that the arrow condition didn’t mean anything to the infants. They reason that to infants, pointing is a result of the close connection between touch and vision and the influence of the adults around them.

Young children, the team writes, “interpret pointing gestures as if they were attempts to touch things, not as arrows.”

This was surprising, says O’Madagain, because “it’s long been assumed that infants at this age are fluent interpreters of pointing gestures and that they treat them more or less as arrows.” That babies overwhelmingly preferred the touch interpretation was an unexpected confirmation of their hypothesis.

Just as we automatically look at what we touch, we look at what other people touch as well. Infants, the research team suspects, notice when adults look at what they touch. Eventually, they figure out they can get adults to look at things by touching them.

“The infant in this way ‘discovers’ the adult’s attention as a thing she can manipulate — and begins to try to direct the adult’s attention to objects further away by making as if to touch those objects,” O’Madagain explains. “In this way the pointing gesture appears, and the coordination of visual attention between humans is set in place, almost as an accidental consequence of the fact that we are inclined to look at what we touch and what other people touch.”

Next, the team will examine whether infants can coordinate their visual attention before pointing at a distance takes place, which occurs around the time infants and adults examine objects together by touching them. They also want to see if other great apes, like chimpanzees, coordinate touch and vision in the same way we do.

“If they don’t,” O’Madagain says, “this could go some way to explaining why they have a hard time understanding pointing gestures which come so naturally to human infants.”

Abstract:

Pointing gestures play a foundational role in human language, but up to now, we have not known where these gestures come from. Here, we investigated the hypothesis that pointing originates in touch. We found, first, that when pointing at a target, children and adults oriented their fingers not as though trying to create an “arrow” that picks out the target but instead as though they were aiming to touch it; second, that when pointing at a target at an angle, participants rotated their wrists to match that angle as they would if they were trying to touch the target; and last, that young children interpret pointing gestures as if they were attempts to touch things, not as arrows. These results provide the first substantial evidence that pointing originates in touch.