Experimenting with Babies
Page 8
THE RESEARCH
In a 2012 study, 9- and 10-month-old babies were shown two video clips in which two actors exchanged a greeting. In one clip, they faced away each other during the greeting, and in the other, they faced each other and gazed into each other’s eyes. Only the 10-month-olds showed a difference in looking times between the two clips—they looked longer at the clip in which the actors were facing away from each other. The researchers interpreted the increase as a response to novelty (in which babies tend to look longer at unexpected things than at expected ones), which suggests that somewhere between 9 and 10 months old, babies come to expect people to look at each other during social interactions.
The fact that the 9-month-old babies failed to make a meaningful distinction between targeted gaze (in which the actors faced each other during their brief conversation) and averted gaze (in which they faced away from each other) suggests that they do not yet understand that targeted gaze is an expectation of social interaction. While they may understand that gazing at something is meaningful in certain contexts (such as when a person is reaching for an object and looks at the object as she reaches for it), they have not yet generalized their understanding of gaze to apply to social situations.
The researchers acknowledge that it’s a little strange that this skill would be acquired in such a short and specific time frame, between 9 and 10 months, and they allow that a more fine-tuned experiment might show that 9-month-olds do have some degree of understanding about social gaze. However, they point out that their experiment, as designed, was simple and straightforward, and revealed a clear difference between the two groups, all of which lends weight to their conclusions.
THE TAKEAWAY
Your baby is becoming a detective. She’s listening in on conversations when you think she’s blissfully unaware, and she’s observing social interactions between other people and constantly forming hypotheses about what rules govern these interactions. Now that you know she’s interested in these tête-à-têtes, give her ample opportunities to observe conversations and other social situations. That doesn’t mean you have to take her to an evening cocktail party to schmooze with socialites; it could be as simple as taking her to the grocery store or letting her sit in the laps of your visiting friends while you reminisce about your preparent days.
Tools of the Trade
One classic way to determine a preverbal infant’s interest level in a particular object, picture, or event is to measure his looking time. For instance, a baby might be presented with two pictures side by side, and the amount of time he spends looking at each picture during a given period might be tallied.
In earlier days, cameras were strapped to an infant’s head in an attempt to indirectly measure their direction of gaze, although this technique could not measure circumstances in which the baby moved his eyes but not his head to redirect his gaze.
Nowadays, most eye-tracking systems use a technique called corneal refraction, in which near-infrared light is reflected off of the eyeball. When corneal refraction systems first became available, the subject’s head had to be kept still, making it impractical for use in infant studies, but since then advances in both the eye-tracking devices and the software used for analysis have made it possible to gather accurate data in spite of infants’ often erratic head movements. Indeed, it’s now possible to determine not only which of two pictures a baby is looking at, but what part of the image he’s focusing on.
The cutting edge of eye-tracking technology involves interpreting eye movements without the need for an infrared light source or any other special equipment, which will make eye tracking studies even simpler to produce.
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Shapes or Kinds?
Age range: 10 months
Experiment complexity: Moderate
Research area: Language development
THE EXPERIMENT
For this experiment, you’ll need two sets of identical-looking containers, such as salt shakers or small bottles. The containers should be opaque, so that their contents cannot be seen from the outside. With each set, fill one of the containers about halfway with salt or sugar. Into the other container, place a hard object, such as a quarter or a stone.
Present your baby with the first set of identical objects. Point to one and say, “Look! There’s a wug!” Point to the other and say, “Look! There’s a zav!” Then pick up each object and shake it, demonstrating the sound it makes. Make note of how long your baby looks at the objects after your demonstration.
A few days later, present your baby with the second set of identical objects. Point to each object and say, “Look! There’s a fep!” Then shake each one. Again, make note of how long your baby looks at the objects after your demonstration.
THE HYPOTHESIS
Your baby will spend more time looking at the objects the second time around, in which both objects were labeled with the same word, than the first time, in which the two objects were labeled with different words.
THE RESEARCH
In a 2009 study, 10-month-old babies were shown two identical-looking objects that made different sounds. With one group of babies, the objects were given the same label; with another group, they were given different labels. The researchers then measured the babies’ looking times after the objects were shaken.
They found that the babies looked longer when the objects were given the same label than when they were given different labels. The researchers interpreted the longer looking times to be a response to something that went against the babies’ expectations. Basically, the babies had expected that objects with the same name would make the same sound, and when the objects instead made different sounds, the babies’ interest was piqued, so they looked longer at the objects.
The results of the study suggest that babies use linguistic information—that is, the words used to label the objects—to predict the internal properties of objects (those unrelated to the object’s appearance). Indeed, they are able to do this even if the objects are identical in appearance. The researchers point out that considering the young age of the subjects, it can be inferred that this is not a skill that is acquired at some point after the process of language acquisition has begun, but instead is present even at the very beginning of word learning.
THE TAKEAWAY
Learning which words map to which objects in a foreign tongue is an extremely difficult task for anyone, let alone someone who is still trying to get acquainted not only with a new language but with the fact that he has fingers and toes. If we were to rely only on an object’s appearance for this word-mapping task, then we would be surprised to learn that a poodle and a Great Dane both share the label dog. But being able to group objects by other characteristics, such as the sound they make, helps resolve some of those problems. Be cognizant of this when you’re helping your baby learn words that refer to things with different appearances. Help him recognize what the things have in common—their sound, their function, their wagging tails—so he can begin to form generalizations and recognize other members of a particular category, even if their appearance is unfamiliar.
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Demonstration and Deduction
Age range: 9–15 months
Experiment complexity: Moderate
Research area: Cognitive development
THE EXPERIMENT
On a flat surface, place a stuffed animal that is able to “hold” a small ball, and to its right, place a plastic cup that contains an identical second ball. Show your baby the objects. Wiggle the stuffed animal around for a second or two, then shake the cup to make the ball rattle inside. Now, take the objects away, remove the ball from the cup, and then put the objects back. Move your baby within reach of the objects and observe her behavior for about 60 seconds. Note whether she removes the ball from the stuffed animal, whether she places it in the cup, and whether she shakes the cup to make the ball rattle.
A few days later, set
up the objects again, but this time, leave the plastic cup empty. As your baby watches, take the ball from the stuffed animal, place it inside the cup, and shake the cup to make the ball rattle inside. Take the objects away, put the ball back to its original position, and then put the objects back. Move your baby within reach of the objects and observe her behavior for about 60 seconds. Again, note whether she removes the ball from the stuffed animal, whether she places it in the cup, and whether she shakes the cup to make the ball rattle.
TWEAK IT
If you are able to perform the experiment on two babies of roughly the same age, you can assign one to each condition, rather than repeating the experiment a few days later. This will eliminate the possibility that your baby’s familiarization with the procedure might skew the results the second time around.
THE HYPOTHESIS
The first time you perform the experiment, your baby is likely to take the ball from the stuffed animal. But what she does next depends on her age. If she’s on the young side, around 9 months old, she’s unlikely to place the ball in the cup, although she may shake the empty cup. If she’s on the older side, around 15 months, she may place the ball in the cup but is unlikely to shake it.
The second time you perform the experiment, your baby is again likely to take the ball from the stuffed animal. If she’s on the young side, her behavior is unlikely to differ significantly from the first time. But if she’s on the older side, she is likely to reproduce your demonstration by placing the ball in the cup and shaking it to make the ball rattle.
THE RESEARCH
In a 2007 study, babies in three age groups—9, 12, and 15 months old—were tested on their ability to learn a three-step sequence. Some of the babies from each age group were placed in a “control” condition, in which they were shown the final step of the sequence (a cup being shaken, and a ball rattling inside) but not the first two steps (the ball being taken from the stuffed animal and then placed in the cup). Other babies were placed in a “demonstration” condition, in which all three steps of the sequence were demonstrated. The babies were then given an opportunity to manipulate the objects, and the researchers took note of how many of the steps each baby was able to complete.
The babies in the 9-month group took the ball from the stuffed animal but otherwise did not show much difference between the two conditions. The demonstration babies in the 12-month group were more likely than the control babies to take the ball from the stuffed animal and place it in the cup, and they exclusively shook the cup after placing the ball inside, while the control babies exclusively shook the cup while it was empty. Babies in the 15-month group performed similarly to those in the 12-month group.
The researchers concluded that at about 9 months old, babies are able to learn the first step in a sequence but don’t yet have the capacity to learn the subsequent steps in the sequence. That soon changes, though. In the demonstration condition, one-third of the 12-month-olds and two-thirds of the 15-month-olds were able to reproduce all three steps in the sequence. However, in these age groups, the babies still need to have all of the steps demonstrated, as evidenced by the fact that none of the babies in the control condition were able to spontaneously perform the sequence. Thus the researchers concluded that by 15 months, babies are able to learn and reproduce the steps in a three-step sequence, but they are not yet able to infer an intermediate step that has not been demonstrated.
THE TAKEAWAY
Your baby might not yet have enough understanding about cause and effect to be able to deduce the steps required to reach a goal, but this study shows that if each of those steps is demonstrated, she may be able to learn and reproduce the sequence. You can help her learn by being very deliberate and methodical when you model a new skill, such as pressing a certain button to turn on a toy and another button to make it play music. Think about all of the steps that the sequence requires, and make sure she sees you perform each step in turn.
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Defending What’s Mine
Age range: 9–24 months
Experiment complexity: Simple
Research area: Social development
THE EXPERIMENT
Arrange a play date for your baby with a child who is about the same age. Select some toys that both babies are likely to be interested in and allow them to play with the toys for about 20 minutes. Both you and the parent of the other child should remain in the room and interact naturally with the children, but for the most part, try to let them play without interference or coaching. Pay special attention to any instances in which one child takes a toy that the other is playing with or has just put down. Note how the other child reacts to the toy being taken away from him: Does he resist, by reaching for the toy and trying to pull it back? Does he cry or use words to protest the toy being taken away? Does he show aggressive behavior (for example, pushing or striking the other child)?
THE HYPOTHESIS
The likelihood of either child reacting in any of these ways to a toy being taken away will vary with age. Children between 9 and 12 months old are significantly more likely to demonstrate resisting behavior than aggressive behavior and very unlikely to use crying or vocalizations as a means of protesting the action. But by 24 months old, children are about as likely to demonstrate resisting and aggressive behavior and much more likely to use crying or vocalizations.
THE RESEARCH
A 2011 study examined the behaviors of children ranging from 9 months old to 30 months old as they interacted with children of roughly the same age. In the majority of play sessions, there was at least one instance of a “takeover,” in which a child picked up a toy that another child was playing with or had recently put down. A minority of children in each age group exhibited negative reactions to their toy being taken away, although the percentage became larger with age. At both 12 months and 24 months old, about 10 percent of children who exhibited such a response used aggression; by 30 months, almost 40 percent did. Crying and vocal protests also rose with age, while resisting behavior decreased with age.
The results of this study show that the use of physical force in response to a toy being taken away by a peer emerges around 12 months, although it is exhibited by only a minority of babies. The researchers note that the use of words such as Mine!—which emerges around age 2—demonstrates that toddlers have already come to learn that it can be useful to make claims on toys. And an analysis of the data that differentiated responses by gender found that boys are more likely to use aggressive protests and girls are more likely to use vocal protests, even though they’re both about as likely to object to the toys being taken away.
THE TAKEAWAY
Whether your child remains composed after a toy takeover will, of course, depend on factors like general temperament, age, and gender. More important is your reaction. If he hits or is otherwise aggressive to the other child, step in and break up the baby scuffle, and if possible, deliver a little discourse on the importance of sharing. If he’s old enough for a time-out to have disciplinary value, it can help reinforce that such behavior is not acceptable. If he’s still too young to learn anything from a time-out, then removing him from the situation will still protect his playmate and give him a chance to calm down.
Don’t Try This at Home
In the mid-1950s, Congress passed a law requiring that safety and prevention measures be devised to minimize the risk of children getting trapped inside refrigerators.
As a response to that law, the journal Pediatrics published “Behavior of Young Children Under Conditions Simulating Entrapment in Refrigerators,” a study that—you guessed it—placed children ages 2 to 5 inside a refrigerator-like box and observed whether they could escape. About a quarter of the kids escaped in fewer than 10 seconds, and about three quarters escaped (or were released) within three minutes.
Among the metrics studied: Success of escape based on the child’s age, size, and behavior; force exerted; time spent inside th
e box; and whether the child cried out for help.
Based on the data from this study, new standards were created for release devices within refrigerators, and for decades, refrigerator manufacturers have been required by federal law to conform to these standards.
A follow-up study eight months later assessed the children to see whether the study had caused any long-term psychological damage, such as reversion to infantile behavior. Fortunately, no children appeared to have been permanently scarred by the experience, although, according to the researchers who conducted the follow-up study, “a number of children still talked about the tests, some with pleasure, a few with resentment.”
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Taking Cues
Age range: 10–12 months
Experiment complexity: Moderate
Research area: Emotional development
THE EXPERIMENT
Select four ordinary household objects of about the same size that your baby will be interested in touching but that are not at all harmful or threatening, such as a ball of yarn, a pack of playing cards, or a small plastic mug. They should be items that your baby has never played with before.
Secure your baby in a high chair or car seat and place two of the items in front of her, out of reach. Stand behind the objects, facing your baby, and direct your gaze at one of the objects. Say, “Look at that.” Then spend about 15 seconds describing the object using a neutral facial expression and neutral voice. (For instance, in the case of the mug, you might say, “It’s plastic. It’s red. It has a handle.”) Finally, say, “Look at that” again. Then move both objects within your baby’s reach, and give her about 30 seconds to play with them. Note which object she is more interested in.