93

Why do infants have an incredible hunger to explore, to reach, to touch, to get into every cleanser-laden cabinet and remove outlet plugs? For the same reason that, if you landed on a different planet, you would need to get the basics of reality down.

Imagine stepping out onto Mars. You would roam the new environment, exploring the rocks and the sand. While exercising your walking schema, or habitual way of physically navigating, you would need to make drastic changes. On Mars, with its minimal gravity, when you took your normal earthling stride, you would probably bounce up 20 feet. Just like a newly crawling infant, you would have to accommodate, and in the process reach a higher mental equilibrium, or a better understanding of life. Moreover, as a scientist, you would not be satisfied to perform each movement only once. The way to pin down the physics of this planet would be to repeat each action over and over again. Now you have the basic principles of Jean Piaget’s sensorimotor stage (see Table 3.7).

Specifically, Piaget believed that during our first two years on this planet, our mission is to make sense of physical reality by exploring the world through our senses. Just as in the above Mars example, as they assimilate, or fit the outer world to what they are capable of doing, infants accommodate and so gradually mentally advance. (Remember my example in Chapter 1 of how, in the process of assimilating this information to your current knowledge schemas or mental slots, you are accommodating and so expanding what you know.)

Let’s take the “everything into the mouth” schema that figures so prominently during the first year of life. As babies mouth each new object—or, in Piaget’s words, assimilate everything to their mouthing schema—they realize that objects have different characteristics. Some are soft or prickly. Others taste terrible or great. Through continual assimilation and accommodation, by age 2, babies make a dramatic mental leap—from relying on a set of reflexes, to reasoning and using symbolic thought.

Circular Reactions: Habits That Pin Down Reality

By observing his own three children, Piaget discovered that driving all these advances were what he called circular reactions—habits, or action-oriented schemas, the child repeats again and again.

94

From the newborn reflexes, during months 1 to 4, primary circular reactions develop. These are repetitive actions centered on the child’s body. A thumb randomly makes contact with his mouth, and a 2-month-old removes that interesting object, observes it, and moves it in and out. Waving her legs captivates a 3-month-old for hours.

At around 4 months of age, secondary circular reactions appear. As the cortex blossoms and the child begins to reach, action-oriented schemas become centered on the outside world. Here is how Piaget described his daughter Lucienne’s first secondary circular reactions:

Lucienne at 0:4 [4 months] is lying in her bassinet. I hang a doll over her feet which . . . sets in motion the schema of shakes. Her feet reach the doll . . . and give it a violent movement which Lucienne surveys with delight . . . . After the first shakes, Lucienne makes slow foot movements as though to grasp and explore . . . . When she tries to kick the doll, and misses . . . she begins again very slowly until she succeeds [without looking at her feet].

(Piaget, 1950, p. 159 [as cited in Flavell, 1963, p. 103])

During the next few months, secondary circular reactions become better coordinated. By about 8 months of age, babies can simultaneously employ two circular reactions, using both grasping and kicking together to explore the world.

Then, around a baby’s first birthday, tertiary circular reactions appear. Now, the child is no longer constrained by stereotyped schemas. He can operate just like a real scientist, flexibly changing his behavior to make sense of the world. A toddler becomes captivated by the toilet, throwing toys and different types of paper into the bowl. At dinner, he gleefully spits his food out at varying velocities and hurls his bottle off the high chair in different directions to see where it lands.

How important are circular reactions in infancy? Spend time with a young baby, as she bats at her mobile or joyously pinwheels her legs. Try to prevent a 1-year-old from hurling plates from a high chair, flushing money down the toilet, or inserting bits of cookie into a USB slot. Then you will understand: Infancy is all about the insatiable drive to repeat interesting acts. (See Table 3.8 for a recap of the circular reactions, as well as a look at the sensorimotor substages.)

Piaget’s concept of circular reactions offers a new perspective on those obsessions that drive adults crazy during what researchers call the little-scientist phase (and parents call the “getting into everything” phase). This is the time, around age 1, when the child begins experimenting with objects in a way that mimics how a scientist behaves: “Let me try this, then that, and see what happens.” The reason you can’t derail a 1-year-old from putting oatmeal into the computer, or clogging the toilet with your hard-earned wages (making a plumber a parent’s new best friend) is that circular reactions allow infants to pin down the basic properties of the world.

Why do specific circular reactions, such as flushing dollar bills down the toilet, become irresistible during the little-scientist phase? This question brings me to Piaget’s ideas about how babies progress from reflexes to the ability to think.

Tracking Early Thinking

How do we know when infants begin to think? According to Piaget, one hallmark of thinking is deferred imitation—repeating an action that was witnessed at an earlier time. When Piaget saw Lucienne, at 16 months of age, mimic a tantrum she had seen another child have days earlier, he realized she had the mental skills to keep that image in her mind, mull it over, and translate it into action on her own. Another sign of reasoning is make-believe play. To pretend you are cleaning the house or talking on the phone like Mommy, you must realize that something signifies, or stands for, something else.

But the most important sign of emerging reasoning is means–end behavior—when the child is able to perform a separate, or different, action to get to a goal. Pushing the toilet lever to make the water swirl down, manipulating a switch to turn on the light, screwing open a bottle to extract the juice—all are examples of “doing something different” to reach a particular end.

95

If you have access to a 1-year-old, you might try to construct your own means–end task. First, show the child something she wants, such as a cookie or a toy. Then, put the object in a place where the baby must perform a different type of action to get the treat. For instance, you might put the cookie in a clear container and cover the top with Saran Wrap. Will the baby ineffectively bang the side of the container, or will she figure out the different step (removing the cover) essential to retrieving what she wants? If you conduct your test by putting the cookie in an opaque container, the baby must have another basic understanding: She must realize that—although she doesn’t see it—the cookie still exists.

Object Permanence: Believing in a Stable World

Object permanence refers to knowing that objects exist even when we no longer see them—a perception that is, obviously, fundamental to our sense of living in a stable world. Suppose you felt that this book disappeared when you averted your eyes or that your house rematerialized out of nothing when you entered your driveway. Piaget believed that object permanence is not inborn. This perception develops gradually throughout the sensorimotor stage.

96

Piaget’s observations suggested that during babies’ first few months, life is a series of disappearing pictures. If an enticing image, such as her mother, passed her line of sight, Lucienne would stare at the place from which the image had vanished as if it would reappear out of thin air. (The relevant phrase here is “out of sight, out of mind.”) Then, around month 5, when the secondary circular reactions are first flowering, there was a milestone. An object dropped out of sight and Lucienne leaned over to look for it, suggesting that she knew it existed independently of her gaze. Still, this sense of a stable object was fragile. The baby quickly abandoned her search after Piaget covered that object with his hand.

Hunting for hidden objects under covers becomes an absorbing game as children approach age one. Still, around 9 or 10 months of age, children make a surprising mistake called the A-not-B error. If you put an object in full view of a baby into one out-of-sight location, have the baby get it, and then move it to another place while the child is watching, she will look for it in the initial place!

See if you can perform this classic test if you have access to a 10-month-old: Place an object, such as a toy, under a piece of paper (A). Then have the baby find it in that place a few times. Next, remove the toy as the infant watches and put it under a different piece of paper (B). What happens? Even though the child saw you put the toy in the new location, he will probably look under the A paper again, as if it had migrated unseen to its original place!

After their first birthday, children seem to master the basic principle. Move an object to a new hiding place and they look for it in the correct location. However, as Piaget found when he used this strategy but covered the object with his hand, object permanence does not fully emerge until children are almost 2 years old.

Emerging object permanence explains many puzzles about development. Why does peek-a-boo become a favorite activity at around 8 months? The reason is that a child now thinks there is probably still someone behind those hands, but doesn’t know for sure.

Emerging object permanence offers a wonderful perspective on why younger babies are so laid back when you remove an interesting object, and then become possessive by their second year of life. Those toddler tantrums do not signal a new, awful personality trait called “the terrible twos.” They simply show that children are smarter. They have the cognitive skills to know that objects still exist when you take them away.

Finally, the concept of object permanence, or fascination with disappearing objects, plus means–end behavior, makes sense of that passion to flush dollar bills down the toilet or the compulsion to stick bits of cookie in a USB port. What could be more tantalizing during the little-scientist phase than taking a new action to get to a goal plus causing things to disappear and possibly reappear? It also explains why you can’t go wrong if you buy your toddler nephew a pop-up toy.

But during the first year of life there is no need to arrive with any toy. Buy a toy for an infant and he will push it aside to play with the box. Your nephew probably prefers fiddling with the TV remote to any object from Toys R Us. Toys only become interesting once we realize that they are different from real life. So, a desire for dolls or action figures—or for anything that requires make-believe play—shows that a child is making the transition from the sensorimotor period to symbolic thought. With the concepts of circular reactions, emerging object permanence, and means–end behavior, Piaget masterfully made sense of the puzzling passions of infant life!

97

Piaget’s insights have transformed the way we think about childhood. Research confirms the fact that children are, at heart, little scientists. The passion to decode the world is built into being human from our first months of life (Gopnik, 2010). However, Piaget’s timing was seriously off. Piaget’s trouble was that he had to rely on babies’ actions (for instance, taking covers off hidden objects) to figure out what they knew. He did not have creative strategies, like preferential looking and habituation, to decode what babies’ understand before they can physically respond. Using these techniques, researchers realized that young infants know far more about life than this master theorist ever believed. Specifically, scientists now know that:

Information-processing researchers use the metaphor of a computer with separate processing steps to decode children’s (and adults’) intellectual skills. For instance, instead of seeing means–end behavior as a capacity that suddenly emerges at age 1, a psychologist using this approach would isolate the talents involved in this milestone—memory, attention, the ability to inhibit your immediate perception—and chart how each skill develops over time.

98

Table 3.9 showcases insights about babies’ memories and mathematical capacities, derived from using this gradual, specific approach. Stay tuned for Chapters 5 and 13, to see how information processing sheds light on memory and thinking during elementary school and old age. Now, it’s time to tackle another question: What do babies understand about human minds?

Social cognition refers to any skill related to managing and decoding people’s emotions, and getting along with other human beings. One hallmark of being human is that we are always making inferences about people’s feelings and goals, based on their actions. (“He’s running, so he must be late.” “She slammed the door in my face, so she must be angry.”) When do these judgments first occur? Piaget would say not before age 2 (or much later) because infants in the sensorimotor period can’t think conceptually. Here, too, Piaget was incorrect. Babies make sophisticated judgments about intentions at an incredibly young age!

The strategy here is to first show infants a video of a puppet or stuffed animal helping another puppet complete a challenging task (the nice puppet). In the next scene, another puppet hinders the stuffed animal from reaching his goal (the mean puppet). (See the photos at right.) Then, the experimenter offers the baby both puppets and sees if she preferentially grabs for either one. And guess what? By the time they can reach (at about month 5), most infants grasp the nice puppet rather than the puppet that acted “mean” (Hamlin & Wynn, 2011; Hamlin, 2013).

This remarkable finding suggests we clue into motivations such as “She’s not nice!” months before we begin to speak (Hamlin, 2013). More astonishing, 8-month-old babies can make adultlike judgments about intentions. They preferentially reach for a stuffed animal that tried to help a puppet, but failed. Here the reasoning may be: “He is a good guy. Even though he didn’t succeed, he tried” (Hamlin, 2013a). Notice that these infants have intuitively mastered modern legal concepts we use in assessing criminal intent. Our system must determine: Was this an accident or did he mean it? He should only be punished if he meant to do harm.

99

But I cannot leave you with the sense that our species is primed to be mini-biblical King Solomons, behaving in a wise, ethical way. Some not-so-appealing human tendencies also erupt before age 1.

Using a similar procedure, the same research group found that 8-month-olds reach for a puppet they previously viewed hindering (acting mean) to another puppet if they view that puppet as different from themselves (Hamlin, 2013b; Hamlin and others, 2013). The principle here seems to be: “The enemy of my enemy is my friend.” Or put more graphically: “I like people who are mean to people who are different than me.” (In the next chapter, you will learn that a fear of anyone different—meaning, not a baby’s primary caregiver—kicks in at exactly 8 months of age!)

In sum, during our second six months on this planet, we can decode intentions—inferring underlying motivations from the way people behave. This mind-reading talent (probably unique to our species) paves the way for that other human milestone: language, communicating our thoughts through words.

Question 3.15

Circular reaction = Darien; means–end behavior = Jai; object permanence = Sam.

Question 3.16

Cognition develops gradually rather than in distinct stages; infants understand human motivations.

Question 3.17

Baby Sara should pick up this idea months before age 1.