14
Picture: Impossible
Age range: 3–6 months
Experiment complexity: Moderate
Research area: Cognitive development
THE EXPERIMENT
Show your child a two-dimensional picture of a structurally possible three-dimensional object and a structurally impossible three-dimensional object (such as the pictures shown below).
THE HYPOTHESIS
Your child will spend more time looking at the picture of the impossible object and will be more likely to explore the impossible picture with his hands by reaching, rubbing, or patting.
THE RESEARCH
A 2007 study involving 4-month-old babies gauged their interest in several two-dimensional pictures of 3D objects by tracking how long they looked at each. The infants were shown a photorealistic picture of a structurally possible wooden cube, and a photorealistic picture of a structurally impossible wooden cube that had been modified in Photoshop. The babies, on average, looked at the impossible picture more than twice as long as the possible one. Even when shown line drawings of the wooden cubes that were not photorealistic and did not have any color, shading, or texture, the babies looked longer at the impossible picture, suggesting that merely depicting the visible surfaces of an object, without other depth cues, is enough to help babies construct a 3D view of the object in their minds.
In a similar 2010 study, 9-month-old babies spent more time touching pictures of wooden cubes that were structurally impossible than pictures of structurally possible ones.
These studies suggest that at a very early age, children are able to demonstrate sophisticated spatial analysis. Specifically, they are able to view two-dimensional depictions of three-dimensional objects, comprehend the objects’ three-dimensional structure, and most astounding, distinguish between the structurally possible and the structurally impossible. This is no easy task. To view a two-dimensional image and discern the implied three-dimensional structure of the object represented by the image one must be able to analyze visual cues such as linear perspective, texture, shadows, and junctions to infer depth.
THE TAKEAWAY
You might think that at 4 months, your baby’s spatial skills are still rudimentary—after all, he’s only recently learned to reach for objects, and it’ll be a few years before he can aim at the toilet with any accuracy. But this study reveals that there are some extremely complicated calculations going on in that cute little head. Don’t underestimate him. Rather, help him further develop his spatial recognition skills by exposing him to artwork with various depth cues, and feel free to mix in works by the likes of M. C. Escher, who specialized in depicting scenes that would be structurally impossible in real life.
15
Pitch Patterns
Age range: 3–9 months
Experiment complexity: Moderate
Research area: Musical development
THE EXPERIMENT
For this experiment, you’ll need to classify the types of sounds your baby makes into two pitch profile categories, depending on whether they rise or fall in pitch. In a notebook, divide a page into two sections. Label one section “Trailing Rise.” This will encompass sounds that have a simple rise in pitch, those that fall in pitch but then rise again, and those that make more than one shift in pitch direction but end with a rise in pitch. Label the other section “Trailing Fall.” This will encompass sounds that have a simple fall in pitch, those that rise in pitch but then fall again, and those that make more than one shift in pitch direction but end with a fall in pitch.
During a period of unstructured play time (a minimum of 15 minutes, but up to an hour if you have the time), make note of any pleasurable “cooing” sounds your baby makes (exclude shrieks and squeals) and place a mark in the category that best fits its pitch profile.
You can repeat this experiment each month between 3 and 9 months.
THE HYPOTHESIS
The trailing fall sounds will predominate. In fact, your baby is likely to make trailing rise sounds only if they are heard as part of your typical interaction with him.
THE RESEARCH
In a 1990 study, researchers visited the homes of 3-month-old babies and recorded their vocalizations during hour-long free-play sessions. They repeated these sessions monthly until the babies were 9 months old. An analysis of the recordings found that more than 80 percent of the vocalizations were trailing fall sounds. A “rise-fall” pitch pattern was the most common pattern of all, constituting 30 percent of all vocalizations. When the researchers analyzed the recordings of the minority of infants who demonstrated frequent trailing rise sounds, they noticed that the babies’ parents or caregivers also made trailing rise sounds and thus concluded that the babies were imitating these pitch patterns. The results of this study are in accord with earlier research finding that preschool-aged children also display a preference for descending pitch.
This was among the first studies to investigate the musical characteristics of the sounds made by babies of this age range. Previous studies on musical development had focused either on the vocalizations made by toddlers and older children or on babies’ reaction to music that was played for them. Among the study’s other findings: The pitch of the babies’ voices did not differ by gender and did not become noticeably higher or lower during the 6 months that they were observed. One of the questions that the study raised was how, and to what degree, a parent’s vocal patterns might influence the types of sounds their baby makes.
THE TAKEAWAY
It’ll be a while before your baby can sing “Somewhere over the Rainbow,” but even at this tender age, he’s hard at work, honing his musical chops by experimenting with pitch changes. And it may be the case, as suggested by this study, that your own expressions of musicality can influence your child’s musical development, so let your own lilting melodies lead the way. Feel free to use this project as a jumping-off point to craft your own experiments. For instance, try to determine whether your baby responds differently when you use trailing fall sounds or trailing rise sounds or see whether your baby is able to imitate the sound profile you make.
16
Spider Sense
Age range: 4–5 months
Experiment complexity: Simple
Research area: Cognitive development
THE EXPERIMENT
Show your baby each of the three images shown below. Image A shows a simple illustration of a spider. Image B shows the same image, but with some features reconfigured. Image C shows the same image, but with the features completely scrambled. You can present the images in any order you choose.
THE HYPOTHESIS
Your baby will look longer at Image A than at either of the other two images.
THE RESEARCH
Throughout history, spiders have been a common, and often avoidable, threat to humans. Being able to recognize a spider, identify it as a threat, and keep away from it is a skill that increases one’s chance of survival.
In a 2007 study, babies were shown three images similar to the ones depicted above. The researchers found a statistically significant difference in the length of their gaze: They looked longer at the unaltered spider image (an average of 24 seconds) than either the partially reconfigured image (16 seconds) or the completely scrambled image (17 seconds).
The researchers posit that through a process of natural selection, humans have acquired an innate mental template of the general shape of a spider. They suggest that this template serves two purposes. First, it allows babies to rapidly acquire a fear response to spiders. Second, it allows humans throughout their life to rapidly detect the presence of a spider and avoid it. Such an inborn ability is not without precedent. The researchers point out that babies exhibit early fear responses to other dangers that small children have encountered throughout history, such as a fear of heights and a fear of adult males. The results of this experiment suggest that a similar
survival instinct is at work when it comes to recognizing the shape of spiders.
THE TAKEAWAY
Hey, cool! Your baby’s got her own Spidey-sense! It may not turn her into a superhero, but it definitely demonstrates that she’s on the alert against arachnid evildoers. If you’d like to extend this experiment, try showing her pictures of other potentially dangerous animals, such as snakes, rats, or narwhals, and gauge her response.
17
Put an Age to That Face
Age range: 4–7 months
Experiment complexity: Complex
Research area: Cognitive development
THE EXPERIMENT
You’ll need to enlist the support of two helpers: a child around age 9 or 10, and an adult of the same gender as the child. Have them practice reciting a nursery rhyme, such as “Humpty Dumpty,” so that their speed, rhythm, and intonation are roughly the same, and then record the voices of each reciting it alone. Now, position both of your helpers side by side in front of your baby, so that he can see both of their faces clearly. Then play the recording of the child’s recitation and have both helpers silently move their lips in sync with the words. Note how long your baby looks at each face during the recitation. Finally, repeat the experiment using the recording of the adult’s recitation.
THE HYPOTHESIS
Your baby will look longer at the child’s face during the child’s recitation and longer at the adult’s face during the adult’s recitation.
THE RESEARCH
A 1998 study tested babies at both 4 months and 7 months. They were shown side-by-side video recordings of an adult and a child reciting a nursery rhyme, while audio from one of the subject’s voices was played in synchronization. When the adult’s voice was played, the babies looked longer at the adult, and when the child’s voice was played, the babies looked longer at the child, demonstrating that the babies were able to match voices to subjects who varied by age. The experiment was modeled on an earlier study showing that babies can match voices to faces based on gender.
There were a few noticeable differences observed between the 4-month-old subjects and the 7-month-old subjects. Across several trials, the 7-month-old babies were adept at matching voices to faces from the start, whereas the 4-month-olds’ ability to match voices to faces improved in the later trials. At 7 months, babies who were regularly exposed to children (such as those with siblings) were best able to match the faces and voices. At 4 months, the level of exposure to children did not make a significant difference.
An additional analysis of the experiment determined that, independent of matched or mismatched voices, the 7-month-old babies showed a strong preference for the child faces over the adult faces, while the 4-month-old babies showed a weak preference for the child faces. Those preferences are consistent with those demonstrated in earlier studies, such as one in which infants responded more positively toward child strangers than adult strangers.
THE TAKEAWAY
Babies can sense that there’s something different between adults and children, and there’s something unique about the latter that is especially fascinating. Well—you knew that, didn’t you? You can now trot out a scientific reason for encouraging older siblings and cousins to interact with your little one. And feel free to repeat this experiment multiple times. Not only will it allow you to track your baby’s progress at face matching as he grows older but it may even teach him a nursery rhyme or two.
Tools of the Trade
One of the problems with using live actors in experiments is the possibility of subtle variances across trials. For instance, if the goal of a study is to determine how babies react to speech delivered in a positive tone versus speech delivered in a negative tone, and a live actor is used in each trial, it’s possible that in one trial the actor’s delivery might be slightly more dramatic or more subdued than in other trials.
Because those subtle variances have the potential to affect the results, researchers tend to prefer using video and audio recordings and computer simulations and animations, when possible. That way, they can be assured that the presentation one subject sees and hears is exactly the same as the presentation that all the other subjects experience.
Indeed, experiments in which babies watch a scene unfold on a computer screen have been growing in popularity, not only because of the consistency they provide across trials but also because they allow researchers to create scenes featuring moving objects that could previously be achieved only by using traditional animation, which was often prohibitively expensive.
18
The Face Matches the Feeling
Age range: 4–12 months
Experiment complexity: Moderate
Research area: Emotional development
THE EXPERIMENT
You’ll perform the following series of tests twice: once when your baby is around 4 months old, and again around your baby’s first birthday. In all cases, make note of your baby’s facial expressions during the tests. First, have a friend smile and tickle your baby’s arms and belly for about 10 seconds. Then offer him a sour substance, such as diluted lemon juice, on a cotton swab. Then restrain your baby’s arm for about 30 seconds (but cut the experiment short if your baby seems distressed).
THE HYPOTHESIS
Your baby’s facial expressions are more likely to fit the situation at 12 months than they are at 4 months. Specifically, his facial expression is more likely to be joyful when being tickled, disgusted when tasting the sour substance, and angry when his arm is restrained.
THE RESEARCH
Babies in a 2005 study were tickled, tasted a sour substance, and had their arm restrained at 4 months and again at 12 months. During each test, their facial expressions were observed and categorized. Researchers found that the babies at 12 months were more likely than they were at 4 months to demonstrate expressions befitting the situation, although even at 12 months, the predominant expression for all but the tickle condition was one categorized as mere interest. And in an additional masked-stranger condition, for which an expression of fear was deemed the appropriate response, only a small percentage of babies had unambiguously fearful expressions, and that percentage remained unchanged between 4 and 12 months. (The researchers hypothesize that facial expression alone may not be the best measure of a fearful response.)
According to a prevailing theory of emotional development, babies at birth have only two basic emotional states: a negative state, in which they cry or exhibit signs of distress, and a positive state. At this stage in their development, a wide range of negative stimuli will cause similar negative responses, and a wide range of positive stimuli will cause similar positive responses. But as babies develop, those emotional states become differentiated, so that one type of negative stimulus, such as a sour taste, will cause one type of emotional response, and another type, such as having an arm restrained, will cause a different response. This differentiation of emotions is called intrasituational specificity. There is a related term, called intersituational specificity, which means that emotional responses that are appropriate to a particular situation become less common in other circumstances. The 2005 study found that the infants they tested showed signs of increasing both intrasituational specificity and intersituational specificity. The findings offer some support to the idea that as infants develop, they respond to specific stimuli with increasingly particular facial expressions.
THE TAKEAWAY
It’s three in the morning, and your newborn is crying. Is it a hunger cry? A cry of pain? Is he wet? Is he scared of the dark? Is his swaddle too restricting? Does he want to be held? Sometimes it can be really tough to know what’s bugging him. Parents often say that as they get to know their babies better, they become more attuned to their babies’ cries and can distinguish an “I need milk” cry from an “I need a new diaper” cry. That may be true, but findings like this suggest that the job also becomes easier because infants’ emotional
expressions become more specific to the situation.
19
Stress Busting
Age range: ~6 months
Experiment complexity: Moderate
Research area: Emotional development
THE EXPERIMENT
Place your baby in a car seat, and place the seat in front of a table so that he has a clear view of the table’s surface. Sit about three feet away, so that he can see you if he turns his head. On the table, close to the car seat, place a toy that is highly stimulating to the senses, such as a fire truck with lights flashing and siren blaring, for about 30 seconds. Then, place the toy within your baby’s reach for about a minute. During this time, don’t interact with him, unless he becomes distressed, in which case, end the experiment. Have a friend make note of your baby’s general emotional state (positive or negative) and his behavior (such as looking away from the toy, sucking his fingers, or trying to touch the toy) throughout the course of the experiment. Later, repeat the experiment, but this time, interact with your baby in any way you wish.
Experimenting with Babies Page 4
