Movement is also a fundamental way to identify whether something is alive or not. For example, aspects of movement tell us when we are dealing with an animal or an object. Objects move in a rigid fashion, whereas animals have a fluid, groovy motion. The next time you are in a shopping mall, watch how other people move. Smoothly and fluidly, shoppers steer and glide past each other to avoid collisions. Machines couldn’t negotiate a busy street full of people. Second, the type of movement is instantly obvious. If you attach luminous reflectors to a person’s forehead, elbows, wrists, knees, and ankles, then turn the room lights off, you see nine separate glowing spots in the dark. However, as soon as that person moves, you immediately see him or her as a person.13 Stop and the person becomes nine stationary points again. That’s because our brains are exquisitely tuned in to the smooth movements of living things even when we can’t see their bodies. It’s so fundamental that when shown these lights point displays, even babies as young as four months see the invisible person.14
Like faces, sometimes movement can fool us into thinking that something has a mind. For example, toys that seem to come alive fascinate children. In my day, one of the popular toys was a piece of finely coiled wire called a ‘Slinky’. It could appear to walk by stretching and lifting up one end over another down an incline, a bit like an acrobatic caterpillar. The attraction of the Slinky on Christmas Day was the lifelike movement it had as it stepped down the stairs before someone trod on it or twisted the spring and ruined it for good. Toys that appear to be alive are curiosities because they challenge how we think inanimate objects and living things should behave. Many toys today exploit this principle to great effect, but be warned: not all babies enjoy objects that suddenly seem lifelike. This anxiety probably reflects their confusion over the question, ‘Is it alive or what?’
Once babies decide that something is alive, they are also inclined to see its movements as purposeful. They are beginning to infer a mind controlling the movements. In one study, twelve-month-olds faced a stuffed toy on a pedestal.15 It looked like a kind of furry brown Russian hat known as a ‘shapka’, with two button eyes for a face. Hardly the most convincing example of a living creature. However, unbeknownst to the baby, the shapka was remotely controlled by scientists hidden in another room. The baby watched the shapka. The shapka watched the baby. It was like the standoff in a spaghetti western. After a short uncomfortable silence, the hat suddenly beeped and moved. The baby was surprised and looked towards its mother for some explanation. None was offered. The baby pointed at the shapka and vocalized. The hat responded back with beeping. The scientists controlling the shapka made sure that it responded to every utterance and movement the infant made. Very soon the baby and hat were engaged in a meaningless but richly synchronized social exchange. When the hat swung around as if to look off to the side, the baby followed suit to see where the shapka was looking. The baby was treating the hat as if it had purpose. Simply by interacting in a synchronized way with the baby’s own responses, the shapka and baby had become the best of buddies.
Babies respond to such exchanges as if the objects are alive and have purpose. They infer intentions. However, if the shapka had simply moved randomly and had not had a face, this social connection would not have been made, and the babies would not have copied or tried to follow the hat’s lead. So movement and faces lead to the inference of intentional purpose. It’s such a powerful combination that it is almost impossible to ignore.
HERE’S LOOKING AT YOU, KID
Humans are natural people-watchers, and most of the time we look at faces and eyes. The focus of another person’s gaze is a very powerful signal for us to look in the same direction. Magic Johnson was a great basketball player because he used the ‘no look’ pass: he could pass the ball to a teammate without taking his eye off his opponent.16 He could control his gaze to hold the other player’s attention and not betray with his eyes where he was about to pass. More impressive was his ability to look toward one teammate and then pass to a completely different person, sending the defender on the opposite team in the wrong direction.
Our difficulty in ignoring the gaze of another person shows what an important component of human social interaction it is.17 They say that the eyes are a window to the soul. I don’t know about souls, but eyes are a pretty good indicator of what someone may be thinking. You can observe this yourself the next time you are standing in line at the supermarket checkout. Just watch the rich exchange of glances between people. It’s remarkable that we are often so unaware of how important the language of the eyes is. This is one reason why it is so unnerving to have a conversation with someone who is wearing sunglasses and we cannot monitor where they are looking. Police officers wear mirrored sunglasses to intimidate suspects for this very reason.
This sensitivity and need to see another’s eyes is present from birth. Newborn babies prefer that we look them in the eye. Even though their vision is so poor that they would qualify for disability allowance,18 they can still make out the eyes on a face, and they prefer the faces of adults whose gaze is directed towards them.19 Since they have little experience of people-watching, this strongly suggests that gaze-watching is another process built in at birth. People in love stare at each other, and parents and babies spend long periods engaged in mutual staring. If you look into the eyes of a three-month-old, the baby will smile back at you. Look away and the smiling stops. Look back and the baby smiles again. Mutual gaze turns the social smiling on and off.20 Not surprisingly, it works in the other direction. If the baby stares, parents smile. They really do have us wrapped around their little fingers.
Gaze is part of a general range of social skills called joint attention.21 When humans interact socially, they do so by sharing the same focus of interest. Whether it is discussing a topic, watching a basketball game, or admiring a painting, we can join in a combined effort to examine the world. Joint attention is not uniquely human; many animals use it to extend their range of potential interests or threats. Like meerkats, who watch each other for the first sign of danger, animals can gain the benefit of watching others watching the world. However, the jury is still out about whether other animals can infer the mental states that humans appear to infer.22 Consider this passage from Barbara Smuts’s ‘What Are Friends For?’:
Alex stared at Thalia until she turned and almost caught him looking at her. He glanced away immediately, and then she stared at him until his head began to turn toward her. She suddenly became engrossed in grooming her toes. But as soon as Alex looked away, her gaze returned to him. They went on like this for more than fifteen minutes, always with split second timing. Finally, Alex managed to catch Thalia looking at him.23
Smuts suggests that Alex and Thalia could be two novices at a singles bar. In fact, this description comes from her field notes of two East African baboons beginning a courtship. It could have been lifted straight out of a scene from Sex in the City, although I would guess that a woman suddenly grooming her toes in public might be considered a bit of a turn-off in New York’s downtown Manhattan. Are animals capable of mind-reading? Certainly they seem to follow gaze, but it is not clear that they can really get to the next stage, which is to think that others have mental states such as beliefs and desires. That is something that seems to be a particulary human quality, and one that infants achieve somewhere between their first year and second year.