Tag Archives: children

What Do Preschoolers Learn from Fantastical Picture Books?

April 16, 2014 By in Science Tags: , , , , 5 Comments

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One of the new picture books making the bedtime rounds at our house is How Do Dinosaurs Say Goodnight?, which describes and depicts dinosaurs doing such un-dinosaurly things as tucking themselves into bed or kissing their human mothers good night. The book is whimsical, gorgeously illustrated, and includes a scientific angle, as the genus names of the dinosaurs are included in the pictures. I’m always careful to read these genus names aloud as we look at each picture. But is this book actually teaching my daughter anything about dinosaurs? And does the misinformation get in the way of her learning these facts? A new study suggests that it might.

Picture books that anthropomorphize animals – and even inanimate objects – are the norm rather than the exception. These books are whimsical and fanciful. They depict worlds like our own but different in magical ways that delight children and adults alike. Perhaps these books are more engaging for young children, fostering lifelong reading habits. Perhaps they stimulate a child’s blossoming imagination. Perhaps – although I would argue that the true story of our diverse, teeming planet is more remarkable than talking teddy bears or hippos in swimsuits.

Look at it this way: everything we do is meant to prepare our children for life in this complex and befuddling world. Why, then, do we feed them so much distorted, inaccurate information? How are they supposed to know what is real and what is fantasy? How is my daughter supposed to know that the three-horned dinosaur was called Triceratops but that it never coexisted with humans nor stomped on its hind legs to protest bedtime?

Researchers in Boston and Toronto looked into this issue and recently published their findings in Frontiers in Psychology. The scientists created picture books based on three animals species that are relatively unknown among North American children: cavies, oxpeckers, and handfish. Their study consisted of two separate experiments. For the first experiment, all of the books featured factual illustrations of the animals, but for each animal the authors made one version of the book with realistic text and one version with text that depicted the animals as human-like. Here are two examples:

Lonely cavy seeks companionship and good conversation.

Lonely cavy seeks companionship and good conversation.

Realistic
When the mother cavy wakes up, she usually eats lots of grass and other plants.
Then the mother cavy feeds her baby cavies.
Mother cavy also licks the babies’ fur to keep them clean.
Mother cavy and her babies spend the rest of the day lying in the sun.
At night, they sleep in a small cave.
After they go to sleep, mother cavy’s big ears help her hear noises around her.

Anthropomorphic
“Yum, those grass and plants are delicious!” Mother cavy thinks as she eats her breakfast.
“I will feed some to my baby cavies too!” she says.
The baby cavies love to play in the grass! But they’ve gotten all dirty! “Time for your bath,” Mother cavy says.
Mother cavy and her babies like to spend the afternoon sunbathing.
At night, Mother cavy tucks her babies in to bed in a small cave. “Mom, I’m scared!” says the baby cavy.
“Don’t be afraid,” she says. “I’ll listen for noises with my big ears and keep us safe.”

Children ages 3 to 5 years old were randomly assigned to read the books with either the factual or fantasy text. After children read one of these books with an experimenter, a second experimenter showed them a picture of the real animal described the story and asked the kids questions about it. Do cavies eat grass? Do cavies talk? Some of these questions tested the factual information kids took away from the picture book, while others tested how much the children anthropomorphized the animal. The children who read the books with talking animals were more likely to say those animals really talk than were children who read the versions with factual text. Still, the two groups were roughly equal in the factual information they retained about the animals.

Oxpeckers ready for adventure.

Oxpeckers ready for adventure.

For the second experiment, the researchers again made two versions of picture books for each animal. This time, both versions showed the animals dressed in clothes, sitting at tables, or engaged in other human activities. As before, the researchers made two versions of each book: one with factual text and one that anthropomorphized the animals. The children who read the fully anthropomorphized picture books tended to believe that the animals really engage in human behaviors like speech. These kids also answered fewer factual questions about the animals correctly (compared with the children who read factual text paired with the fantastical pictures).

These findings have two major implications. First, picture books that anthropomorphize animals seem to actually teach children that animals think and behave like humans. In one sense you might say this is good, as it could discourage animal cruelty and abuse. But in another sense, it’s highly unproductive. At the very best, children will have to unlearn all of this nonsense. At worst, they will carry some of this misinformation about the natural world throughout life – probably not as a belief in talking animals, but in the assumptions they make about the thoughts, feelings, and intentions of other species.

The other takeaway is that the whimsical aspects of a picture book may be sabotaging your child’s learning of the real information in these stories, particularly when the illustrations and text both reflect fantasy.  Since children can’t conclusively tell fact from fiction, some may be discounting all information from highly fanciful stories – including incredible-yet-true facts like the chameleon’s mercurial skin tone or the transformation of caterpillar into butterfly. As the authors write in their paper: “if the goal of the picture book interaction is to teach children information about the world, it is best to use books that depict the world in a realistic rather than fantastical manner.” Of course that takes enthusiasm out of the equation. What kid would sit for hours watching videos of real trains when he or she could watch Thomas? Human narrative adds interest, but it also seems to muddle up real learning, at least in preschoolers.

I hate to build an argument against imaginative, fanciful picture books. What am I, Scrooge? But while I love imagination, I don’t love misinformation – particularly scientific misinformation. And while I love magic, I don’t love magical thinking or flawed reasoning about the natural world. I’m not saying you should throw away your copy of Goodnight Moon and all things Sandra Boynton – just keep in mind that wee ones don’t always know real from fanciful or facetious. Talk about these concepts with them. Buy some nonfiction picture books with accurate information about animals and keep them in the lineup. And know that, for all your efforts, they may come away believing that trains talk and bunnies knit . . . at least for now.

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Photo credits:  Mother and child by KatLevPhoto, cropped for use here; cavy by Brent Moore; oxpeckers by Steve Garvie. All used via Creative Commons license

Ganea, P., Canfield, C., Simons Ghafari, K., & Chou, T. (2014). Do cavies talk? The effect of anthropomorphic picture books on children’s knowledge about animals Frontiers in Psychology, 5 DOI: 10.3389/fpsyg.2014.00283

Known Unknowns

January 5, 2014 By in Brains, Pregnancy, Science Tags: , , , , , 1 Comment

Why no one can say exactly how much is safe to drink while pregnant

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I was waiting in the dining car of an Amtrak train recently when I looked up and saw that old familiar sign:

“According to the Surgeon General, women should not drink alcoholic beverages during pregnancy because of the risk of birth defects.”

One finds this warning everywhere: printed on bottles and menus or posted on placards at restaurants and even train cars barreling through Midwestern farmland in the middle of the night. The warnings are, of course, intended to reduce the number of cases of fetal alcohol syndrome in the United States. To that end, the Centers for Disease Control and Prevention (CDC) and the American Congress of Obstetricians and Gynecologists (ACOG) recommend that women avoid drinking any alcohol throughout their pregnancies.

Here’s how the CDC puts it:

“There is no known safe amount of alcohol to drink while pregnant.”

And here’s ACOG’s statement in 2008:

“. . . ACOG reiterates its long-standing position that no amount of alcohol consumption can be considered safe during pregnancy.”

Did you notice what they did there? These statements don’t actually say that no amount of alcohol is safe during pregnancy. They say that no safe amount is known and that no amount can be considered safe, respectively. Ultimately, these are statements of uncertainty. We don’t know how much is safe to drink, so it’s best if you don’t drink any at all.

Lest you think this is a merely a reflection of America’s puritanical roots, check out the recommendations of the U.K.’s National Health Service. While they make allowances for the fact that some women choose to drink, they still advise pregnant women to avoid alcohol altogether. As they say:

“If women want to avoid all possible alcohol-related risks, they should not drink alcohol during pregnancy because the evidence on this is limited.”

Yet it seems odd that the evidence is so limited. The damaging effects of binge drinking on fetal development were known in the 18th century and the first modern description of fetal alcohol syndrome was published in a French medical journal nearly 50 years ago. Six years later, in 1973, a group of researchers at the University of Washington documented the syndrome in The Lancet. Even then, people knew the cause of fetal alcohol syndrome: alcohol. And in the forty years since, fetal alcohol syndrome has become a well-known and well-studied illness. NIH alone devotes more than $30 million dollars annually to research in the field. So how come no one has answered the most pressing question (at least for pregnant women): How much is safe to drink?

One reason is that fetal alcohol syndrome isn’t like HIV. You can’t diagnose it with a blood test. Doctors rely on a characteristic pattern of facial abnormalities, growth delays and neural or mental problems – often in addition to evidence of prenatal alcohol exposure – to diagnose a child. Yet children exposed to and affected by alcohol during fetal development don’t always show all of these symptoms. Doctors and agencies now define fetal alcohol syndrome as the extreme end of a spectrum of disorders caused by prenatal alcohol exposure. The full spectrum, called fetal alcohol spectrum disorders (FASD), includes milder forms of the illness that involve subtler cognitive or behavioral problems and lack the classic facial features of the full-blown syndrome.

As you might imagine, milder cases of FASD are hard to identify. Pediatricians can miss the signs altogether. And there’s a fundamental difficulty in diagnosing the mildest cases of FASD. To put it crudely, if your child is slow, who’s to say whether the culprit is a little wine during pregnancy, genetics, too much television, too few vegetables, or god-knows-what-else? Unfortunately, identifying and understanding the mildest cases is crucial. These are the cases that worry pregnant women who drink lightly. They lie at the heart of the uncertainty voiced by the CDC, ACOG, and others. Most pregnant women would like to enjoy the occasional merlot or Sam Adams, but not if they thought it would rob their children of IQ points or otherwise limit their abilities – even just a little – down the line.

While it’s hard to pin down the subtlest cases in the clinic, scientists can still detect them by looking for differences between groups of children with different exposures. The most obvious way of testing this would be to randomly assign pregnant women to drink alcohol at different doses, but of course that experiment would be unethical and should never be done. Instead, researchers capitalize on the variability in how much women choose to drink during pregnancy (or at least how much they report that they drank, which may not always be the same thing.) In addition to interviewing moms about their drinking habits, the scientists test their children at different ages and look for correlations between prenatal alcohol exposure and test performance.

While essential, these studies can be messy and hard to interpret. When researchers do find correlations between moderate prenatal alcohol exposure and poor test performance, they can’t definitively claim that the former caused the latter (although it’s suggestive). A mysterious third variable (say, maternal cocaine use) might be responsible for them both. On the flip side, interpreting studies that don’t find correlations is even trickier.  It’s hard to show that one thing doesn’t affect another, particularly when you are interested in very small effects. To establish this with any confidence, scientists must show that it holds with large numbers of people and that they are using the right outcome measure (e.g., IQ score). FASD impairments can span language, movement, math skills, goal-directed behaviors, and social interactions. Any number of measures from wildly different tests might be relevant. If a given study doesn’t find a correlation between prenatal alcohol exposure and outcome measure, it might be because the study didn’t test enough children or didn’t choose the right test to pick up the subtle differences between groups.

When studies in humans get tricky, scientists often turn to animal models. FASD research has been no exception. These animal studies have helped us understand the physiological and biochemical mechanisms behind fetal alcohol syndrome, but they can’t tell us how much alcohol a pregnant woman can safely drink. Alcohol metabolism rates vary quite a bit between species. The sensitivity of developing neurons to alcohol may differ too. One study used computational modeling to predict that the blood alcohol level of a pregnant rat must be 10 times that of a pregnant human to wreak the same neural havoc on the fetus. Yet computational models are far from foolproof. Scientists simply don’t know precisely how a dose in a rat, monkey, or other animal would translate to a human mother and fetus.

And here’s the clincher: alcohol’s prenatal effects also differ between humans. Thanks to genetic differences, people metabolize alcohol at very different rates. The faster a pregnant woman clears alcohol from her system, the lower the exposure to her fetus. Other factors make a difference, too. Prenatal alcohol exposure seems to take a heavier toll on the fetuses of older mothers. The same goes for poor mothers, probably because of confounding factors like nutrition and stress. Taken together, these differences mean that if two pregnant women drink the same amount of alcohol at the same time, their fetuses might experience very different alcohol exposures and have very different outcomes. In short, there is no single limit to how much a pregnant woman can safely drink because every woman and every pregnancy is different.

As organizations like the CDC point out, the surest way to prevent FASD is to avoid alcohol entirely while pregnant. Ultimately, every expecting mother has to make her own decision about drinking based on her own understanding of the risk. She may hear strong opinions from friends, family, the blogosphere and conventional media. Lots of people will seem sure of many things and those are precisely the people that she should ignore.

When making any important decision, it’s best to know as much as you can – even when that means knowing how much remains unknown.

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Photo Credit: Uncalno Tekno on Flickr, used via Creative Commons license

Hurley TD, & Edenberg HJ (2012). Genes encoding enzymes involved in ethanol metabolism. Alcohol research : current reviews, 34 (3), 339-44 PMID: 23134050

Stoler JM, & Holmes LB (1999). Under-recognition of prenatal alcohol effects in infants of known alcohol abusing women. The Journal of Pediatrics, 135 (4), 430-6 PMID: 10518076

Flipping the Baby Switch

May 29, 2013 By in Brains, Kids, Pregnancy Tags: , , , , 6 Comments

img_2348-1Rewind to last night. It was bedtime. My infant daughter was screaming and struggling in my lap while I tried to rock her to sleep. She pulled and twisted the skin on my face. She sunk her tiny teeth into my shoulder and chest. Exasperated, I rose from the rocker and started pacing around the nursery. Her tense little body instantly relaxed. Within ten seconds she was quiet and still. Within two minutes she was asleep.

The scene was not unusual for our household. Even as a newborn, my daughter was easy to upset and hard to soothe. When nothing else worked and I was about to lose my mind I’d get up and walk with her. Often the results were nothing short of miraculous. Imagine going from 100 miles per hour to zero in a snap. For those who recall the child android Vicki on the ‘80s TV show Small Wonder, think of the times someone flipped the off-switch on her back. That’s what it’s like when I walk with my daughter. Our aimless walking flips a switch somewhere inside of her. But how does the switch work? And why does she have one in the first place? A study published in Current Biology last month helps to explain this curious facet of infant behavior.

The head scientist behind the study was Dr. Kumi Kuroda at the RIKEN Brain Science Institute in Japan. As she described in an interview with ScienceNOW, she became interested in the topic when she noticed that she could calm her own newborn son by carrying him. She later tested 12 other newborns with their mothers and found that they behaved like her son. Overall, the effect was rapid and dramatic. Some babies stopped crying as soon as their mothers began to walk with them. The rest cried less and were less shrill when they did cry. The babies also moved less and had lower heart rates while they were being carried.

To study the biological mechanisms behind this remarkable calming response, Dr. Kuroda and her colleagues turned to mice. They showed that mouse pups have a similar response when carried by their mothers. Mouse moms carry their pups by the scruff of their necks. When carried, mouse pups less than 20 days old stop wriggling. Their heart rate slows and they stop crying out. (Like most mouse vocalizations, baby mouse cries are ultrasonic). They also draw their legs in when carried, making their bodies more compact for toting around.

Kuroda and colleagues investigated several physiological aspects of the calming response in mice. Only a few of these experiments are probably relevant for infants, since human babies don’t assume a compact position like carried mouse pups do. One looked for the triggers that make carried pups stop squirming. The scientists anesthetized the neck skin of baby mice and found that these animals wriggled more than untreated mouse pups when carried. They got the same result when they overdosed pups with vitamin B6 before testing. (Vitamin B6 overdose causes animals and humans to lose the sense of their body position and movement.) The upshot? For a mouse pup to stop wriggling when carried it must 1) sense that it’s being lifted and 2) sense that something is pulling on its neck skin. Take either sense away and the calming response disappears. My daughter may draw on similar senses to trigger her miraculous stillness while carried. (Only if you replace neck pulling with the pressure of my arms around her, of course. I don’t carry her by her neck skin, I swear.)

The scientists also wondered why a baby’s heart rate drops when it’s picked up and carried. To test this in mice, they gave pups a drug that turns down the parasympathetic nervous system (the set of nerves that return the body to a calm state after arousal). Pups treated with the drug still stopped wriggling when lifted, but their heart rates didn’t drop as they do in untreated pups. So while the parasympathetic nervous system slows down the carried pup’s (and possibly infant’s) heartbeat, it can’t take credit for other features of the calming response.

Clearly this calming response is more complicated than it seems. Many of my daughter’s brain areas, neural pathways, and sensory mechanisms were working in concert to soothe her last night as I walked her in circles. But why does she have this complex reaction to carrying in the first place? Grateful parents might imagine that the calming response evolved to keep us from going crazy, but unless going crazy involves committing infanticide, this explanation doesn’t hold water. Evolution doesn’t care whether parents are happy or well rested or have time to watch Game of Thrones. It only cares whether our offspring survive.

Dr. Kuroda and her colleagues propose that the calming response helped parents escape dangerous situations while protecting their young. According to this logic, calmer carried babies meant faster escapes and higher rates of survival. Certainly if you were running from a wild beast or a member of a rival village, holding a struggling infant might slow you down. Of course holding any infant would slow you down and it’s not clear that sprinting with a struggling newborn is much harder than lugging one that’s asleep.  The paper’s authors present little evidence to support their proposal, particularly in the context of human evolution. They point to a minor result with their mice that doesn’t easily translate to human behavior. In effect, the jury’s still out.

There are other possible explanations for the calming response, ones that don’t involve predators outrunning parents. Shushing can calm crying babies too, probably because it simulates an aspect of their environment in the womb (in this case,  physiological noise). The same could be true of walking with infants. The mothers in the Kuroda study held their babies against their chest and abdomen, which is also how I hold my daughter when I walk to soothe her. The type of movement she feels in that position is probably similar to the rocking and jostling she felt as a fetus in utero whenever I walked. If so, the calming response might be a result of early learning and comfort by association – a nice thought when you consider the gory alternative.

Each year at the end of May we find ourselves as far as possible from Thanksgiving Day. It can be something of a thankfulness drought. This May I am thankful for women in science and maternity leaves, computer-generated dragons and ’80s sitcom androids. And like Vicki’s parents, I am profoundly thankful that my daughter came furnished with an off-switch. Whatever the reason why.

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Photo credit: Sabin Dang

Esposito G, Yoshida S, Ohnishi R, Tsuneoka Y, Rostagno Mdel C, Yokota S, Okabe S, Kamiya K, Hoshino M, Shimizu M, Venuti P, Kikusui T, Kato T, & Kuroda KO (2013). Infant Calming Responses during Maternal Carrying in Humans and Mice. Current biology : CB, 23 (9), 739-45 PMID: 23602481

Pb on the Brain

March 31, 2013 By in Brains, Kids Tags: , , , 2 Comments

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I’ve got lead on my mind. Lead the element, not the verb; the toxic metal that used to grace every gas tank and paint can in this grand country of ours. For the most part we’ve stopped spewing lead into our environment, but the lead of prior generations doesn’t go away. It lingers on the walls and windows of older buildings, on floors as dust, and in the soil. These days it lingers in my thoughts as well.

I started worrying about lead when my daughter became a toddler and began putting everything in her mouth. I fretted more when I learned that lead is far more damaging to young children than was previously thought. Even a tiny amount of it can irreversibly harm a child’s developing brain, leading to lower IQs, attention problems and behavioral disorders. You may never even see the culprit; lead can sit around as microscopic dust, waiting to be inhaled or sucked off of an infant’s fingers.

Public health programs use blood lead levels (BLLs) to evaluate the amount of lead in a child’s system and decide whether to take preventative or medical action. In the 1960s, only BLLs above 60 μg/dL were considered toxic in children. That number has been creeping downward ever since. In 1985 the CDC’s stated blood lead level of concern became 25 μg/dL and in 1991 it went down to 10. But last year the CDC moved the cutoff down to 5 μg/dL and got rid of the term “level of concern.” That’s because scientists now believe that any amount of lead is toxic. In fact, it seems as if lead’s neurotoxic effects are most potent at BLLs below 5 μg/dL. In other words, a disproportionately large amount of the brain damage occurs at the lowest doses. Recent studies have shown subtle intellectual impairments in kids with BLLs as low as 2 μg/dL (which is roughly the mean BLL of American preschoolers today). All great reasons for parents to worry about even tiny exposures to lead, no?

Yes. Absolutely. Parents never want to handicap their children, even if only by an IQ point or two. But here’s what’s crazy: nearly every American in their fifties, forties, or late-thirties today would have clocked in well over the current CDC’s cutoff when they were little. The average BLL of American preschoolers in the late ‘70s was 15 μg/dL – and 88% had BLLs greater than 10 μg/dL.

These stats made me wonder if whole generations of Americans are cognitively and behaviorally impaired from lead poisoning as children. Have we been blaming our intellectually underwhelming workforce on a mismanaged education system, cultural complacency, or the rise of television and video games when we should have been blaming a toxic metal element?

I was sure I wasn’t the first person to wonder about the upshot of poisoning generations of Americans. And lo and behold, a quick Google search led me to this brilliant article on Mother Jones from January. The piece chronicles a rise in urban crime that began in the ‘60s and fell off precipitously in the early-to-mid ‘90s nationwide. The author, Kevin Drum, walks readers through very real evidence that lead fumes from leaded gasoline were a major cause of the rise in crime (and that increased regulation restricting lead in gasoline could be credited for the sudden drop off.)

The idea certainly sounds far-fetched: generations of city-dwellers were more prone to violence as adults because they breathed high levels of lead fumes when they were kids. It doesn’t seem possible. But when you put the pieces together it’s hard to imagine any other outcome. We know that children of the ‘50s, ‘60s, and ‘70s had BLLs high enough to cause irreversible IQ deficits and behavioral problems (of which aggression and impulse control are particularly common). Why is it so hard to imagine that more of these children behaved violently when they became adults?

In the end, this terrible human experiment in mass poisoning has left me pondering two particular questions. First, what does it mean for generations of children to be, in a sense, retroactively damaged by lead? At the time, our levels were considered harmless, but now we know better. Does knowing now, at this point, explain anything about recent history and current events? Does it explain the remarkable intransigence of certain politicians or the bellicosity of certain talk show hosts, athletes, or drivers with a road rage problem? Aside from the crime wave, what other sweeping societal trends might be credited to the poisoning of children past? How might history have played out differently if we had all been in our right minds?

Finally, I’ve been thinking a lot about the leads and asbestoses and thalidomides of today. Pesticides? Bisphenol A? Flame retardants? What is my daughter licking off of those toys of hers and how is it going to harm her twenty years down the line? This is not just a question for parents. Think crime waves. Think lost productivity and innovation. Today’s children grow up to be tomorrow’s adults. Someday when we are old and convalescing they’ll take the reigns of our society and drive it heaven-knows-where. That makes child health and safety an issue for us all. We may never even know how much we stand to lose.

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Photo credit: Zara Evens

Tooling Around

September 16, 2012 By in Brains, Kids Tags: , , , , , 2 Comments

tools1There was a time when my daughter used her hands exclusively to shovel things into her mouth. Not so anymore. For the last few months, she has been hard at work banging objects together. This simple action is setting the stage for some pretty cool neural development. She is learning to use tools.

Of course it doesn’t look too impressive right now. She might bang a ball with a block and then switch and strike the block with the ball. In one recent playtime she tore a cardboard flap out of her board book and examined it, trying different grips and holding it from different angles as she watched how it cut the air. Then, brandishing her precious flap, she went to work. She wielded it with a scooping motion to lift other flaps in the book, and later, to turn the book pages themselves. After that, she descended on her toy box with the flap. She used it to wipe her blanket, poke her stuffed animal, and finally scrape its face like she was giving it a close shave.

Although my daughter’s fun with flaps may seem aimless, it had an important purpose. Through experimentation and observation, she was learning how two objects can interact and how such interactions are affected by object shape, configuration, and pliability. Such details are so well known to adults that we forget there was anything to learn. But consider how often we use objects against one another. We hammer nails, rake leaves, and staple pages. When using scissors, we must apply different levels of force to cut through paper versus cardboard or fabric. When lifting a pan with a potholder, we must adjust our grip depending on the weight of the pan and whether we are lifting it by the base, side, or handle. We must know the subtle differences between holding a sponge to wash a glass and using a towel to dry it, and we must do each deftly enough that our glassware comes out clean and intact at the end.

There are also countless tools we create on the fly every day. When you use a magazine to nudge your cell phone within reach or flip a light switch with a book because your hands are full, you are devising novel tools to fit your momentary needs. To do this, our brains must store extensive knowledge about the properties of household objects. Through experimentation, like the kind my daughter is doing, we learned to predict how objects will interact and to capitalize on those predictions.

So far I’ve described the value of tools in terms of what they can do: push, pull, gather, polish, lift, etc. But there is another side to tool use that may play a role in my daughter’s little experiments: sensory information gleaned through the tool. As I watched her probe one object with another, I was reminded of research described in Sandra and Matthew Blakeslee’s book The Body Has a Mind of Its Own. The book discussed neurons in the parietal cortex that are tuned to the sight or feel of objects near a particular body part. For example, cells representing your right hand would fire if something touched your right hand, if you saw an object near your right hand, or both. Neuroscientists have discovered that experience using a tool can change the properties of these cells in monkeys (and therefore likely in us as well). They found that if monkeys used a rake to gather goodies otherwise beyond their reach, the parietal neurons that had responded to objects around the hand now fired for items located anywhere along both the hand and the rake it held. In a sense, object manipulation can temporarily extend certain neural body representations to include the tools we wield. The Blakeslees suggest that this may be how a blind person learns to perceive the contour of items encountered at the tip of his cane. In effect, the cane and the hand are one.

For now, our house is filled with smashing, scraping, banging and bending as our baby descends on toys and her parents’ belongings alike. In the midst of such havoc, it’s good to know that the destruction is part of a crucial learning process. And someday, once it slows down, I can buy her a new board book with all the flaps intact.

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Photo credit: zzpza

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