Category: science

Chocolate Lovers Are Sweeter!

Posted in Chocolate Babies, parenting, pregnancy, science by jenapincott on November 15, 2011

Not long ago, someone emailed me a new study on chocolate and temperament. The study came from a group of psychologists at North Dakota State University and Gettysburg College, and it involved personality differences between people who liked sweet foods versus bitter, spicy, sour, salty, or umami flavors. The researchers wanted to know, “Is having a sweet tooth related to having a sweeter disposition?”

Here’s a sample of what they asked their hundred or so volunteers.

Candy, caramel, chocolate cake, honey, ice cream, maple syrup, pears, raisins, strawberries, and sugar. How fond were they of these dessert flavors?

The volunteers rated their taste preferences on a scale of 1-10.

Following that, they completed an agreeableness scale. That is, they were asked to indicate the extent to which they behave in ways reflective of high (e.g., “have a soft heart”) versus low (e.g., “insult people”) levels of agreeableness.

Pleasingly, the researchers found a significant correlation. People who loved sweets were likelier to be more agreeable.

“Further proof that chocolate lovers would have sweeter babies!” my sender gushed. There’s logic here: If people with a sweet tooth really have a sweeter disposition then women who love sweets might have more agreeable babies because disposition is heritable. Equally valid, people who have sweeter dispositions would have a gentler parenting style, resulting in babies with sweeter dispositions. Ergo, chocolate lovers have sweeter babies. Natch.

Then the researchers took their study to the next level to see if sweet-toothed types not only test as more agreeable, but act sweeter too.

At the end of the session, participants were told that the study was over and that full participation credit would be awarded, thereby relieving them of any further obligations. However, it was mentioned that a colleague in the English department was collecting data on media preferences and was looking for volunteers.

Interestingly, people who had a sweet tooth were more likely to complete the voluntary survey, even though they weren’t getting any extra credit or compensation.

Such sweethearts!

I wonder: does the mere suggestion of sweet food make people act sweeter? Does sweet food make people less angry and aggressive? The researchers claim that metaphors can be predictive about behavior and personality. Because “sweet” in English applies to both taste and disposition, does the correlation still apply in different languages?

How sweet would that be?

How Might Motherhood Prevent Dementia?

Posted in Chocolate Babies, parenting, pregnancy, psychology, science by jenapincott on October 31, 2011

Among the great mysteries — and horrible injustices — of aging is that dementia strikes more women than men. No one knows why exactly.  For years, scientists suspected that the culprit is estrogen. Implicated in memory formation, estrogen levels plummet after women reach menopause.

But here’s the catch.  If low estrogen levels are behind age-related dementia in women, then why did a massive study by the National Institute of Health find that women who had hormone replacement therapy (HRT) were no less likely to experience cognitive decline than women who didn’t have it?

Because not all estrogens are created equal, nor are all brains.  Motherhood may be the missing link.

This comes from an intriguing new study by Cindy Barha and Liisa Galea, neuroscientists at the University of British Columbia’s Brain Research Center.  Barha and Galea knew that the female brain is highly plastic; it literally restructures itself in the course of pregnancy and caring for a baby.  They were curious about whether motherhood might alter the brain in a way that protects against dementia under certain conditions.

One way to explore this is to study middle-aged rats that are genetically identical in every way with the exception of their reproductive lives.  The scientists divided the rats into groups — virgins and mothers — and injected each with a form of estrogen:  estradiol or estrone (the form in HRT).  Later, they looked at the rats’ brain tissue to see whether new cells had formed — a process called neurogenesis — in the hippocampus where memories are formed.  These new cells may reduce the risk of dementia.

It’s interesting, this contest between middle-aged virgins and mothers.  Compared to virgins who had been injected with estrogens (and mothers who hadn’t), the middle-aged mother rats that took the hormone replacement therapy grew significantly more new hippocampal cells.  The mothers — and only the mothers — grew many new neurons when exposed to the estrogens (especially a combination of estrone and 17a-estradiol).  The hormones helped the mothers’ minds to remain malleable.

Why did the mothers have a seeming advantage?  Anther mystery — which Barha and Galea say may be related to an enhanced ability of mothers’ hippocampuses, even late in life, to respond to estrogens.  Such responsiveness may come from hormone exposure during pregnancy or afterward, or enrichment from the experience of mothering.

Interestingly, estradiol’s effect on the brain is mediated by BDNF (brain derived neurotrophic factor levels), which may be higher in mothers than in those who have not given birth. The researchers note that BDNF may help explain an assocation between high levels of estrogen exposure across a lifespan and a decreased risk of cognitive decline and Alzheimer’s disease. Among rats, those who have been mothers have a reduced age-related decline in spatial memory and other cognitive decline.

The scientists conclude:

Therefore previous reproductive experience, which is associated with altered hormone exposure and greater enrichment, can result in higher levels of plasticity in the middle-aged brain and may protect the brain from the deleterious effects of aging in females.

But there’s a very real caveat.  Applied to humans, these findings are still highly speculative. First, the boost would depend on a woman taking hormone replacement therapy, which remains controversial due to its connection with breast cancer.  (Why hasn’t HRT been shown to improve cognition thus far?  It may because a combination of estrone and 17a-estradiol is much more effective than the current regimen of estrone and progestin.)

More importantly, there is no guarantee that new neurons will improve a person’s ability to learn and remember or decrease the risk of cognitive decline.  As Barha and Galhea warn, all that new growth might even lead to a sort of jungle effect if not properly integrated.  There are clearly other factors that determine what properties these new cells will have as they mature.  Do some mothers put their new neurons to use more effectively than others?  No one knows whether or how, but the question is fascinating.  (More research is underway in Barha and Galea’s lab.)

What’s clear is that motherhood results in permanent changes in the brain.  Will we mothers someday benefit cognitively more than childless women from new hormonal therapies? There’s a chance.  Wouldn’t it be marvelous if a cognitive boost later in life would compensate for all the sleepless nights now?

*If you like this blog, click here for previous posts. If you wish, check out my new book,  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

 

 

 

“Chocolate Lovers” in Urban Baby!

Posted in Chocolate Lovers, media, parenting, pregnancy, science by jenapincott on October 22, 2011

Today I was thrilled to see a mention of Chocolate Lovers in one of my favorite parenting sites, Urban Baby.

The Plight of the Pregnant Male — Wall Street Journal

Posted in Chocolate Lovers, parenting, pregnancy, psychology, science by jenapincott on October 15, 2011

Here’s my essay touching on some fun science behind  fatherhood, The Plight of the Pregnant Male, in this weekend’s WSJ review.

 

 

What Does Motherhood Do to Your Image?

Posted in Chocolate Lovers, parenting, pregnancy, psychology, science by jenapincott on October 11, 2011

 

For months I’ve had a hunch that having a baby has been better for my husband’s image than mine. I don’t mean his looks. Neither of us has had much time to sleep and shower and pay attention to clothing and hair. What I mean is that I think first impressions favor fathers more than mothers.  Pushing our baby along in the stroller, holding a coffee cup and singing, I fall into an easy stereotype, but my husband doesn’t. Yes, in terms of public image, I believe a man benefits more from being a father than a woman benefits from being a mother.

Am I right?

A couple years ago, Ariane Kemkes, a researcher at the Tholius Institute for Research in Applied Demography in Scottsdale, Arizona, asked the same question. Kemkes wondered what would happen if you took a picture of a parent sitting next to his or child, and impartial judges rate that parent in terms of attractiveness, smarts, success, and so on.  Then, she wondered, what would happen if you crop the child out of the photo and ask a different set of judges to rate them on the same criteria?

Are men and women judged differently when they’re with kids than without?  And if so, do fathers benefit from a bigger boost in their social image than do mothers?

The results are intriguing to us new parents.

Men perceive mothers and fathers differently than women do. Looking at a photo of mother and child, male judges are 2.4 times more likely than female judges to believe that the woman is committed to family. Female judges were more cynical and critical of other women’s maternal commitment (but more interested in meeting them). Surprisingly – and to my relief – both sexes are marginally (1.1 times for men, 1.2 for women) more likely to think a woman looked more attractive with a child than when she was alone.  Men, however, were more ambivalent abot meeting women if they were mothers. A mother was also perceived by judges of both genders as slightly, but not significantly, more faithful, honest, and mature.

But what about her mind?  Here comes the crux of my argument about the drawbacks of motherhood.  If a woman was paired with her child, both male and female judges perceived that woman to be less ambitious than if she was alone.  The presence of a child around a woman reduced the woman’s likelihood of being regarded as ambitious by as much as 30 percent.  The assumption by men is unsurprising, but that the stereotype is held by other women is startling. The results may make one pause on bring-your-child-to-work day.

And now, what about men — what does fatherhood do to their image?

Only good things, as I presumed.

Men with children were perceived by all as being committed to family.  Interestingly, fatherhood was good for a man’s social life.  Men were 1.2 times more interested in meeting fellow a man with a child than the same man without a child. And here’s another perk of fatherhood: A man with a child  is perceived to be  of a higher social status.  This comes from judges of both genders. Fathers are also believed to be more faithful, mature, honest.  They’re also thought to be more generous – a perception not transferred to women with children.

Kemkes sums up the stereotype: females most often associate maternity as conflicting with career and leisured activities, while males emphasize financial sacrifices.  A childless woman is perceived as ambitious and a childless male is perceived as cash-strapped, immature, or having a lower social status.  For men, there is a strong association, explainable in evolutionary terms, between reproductive and financial status that does not exist for women.

Moreover, as Kemkes points out, men who are fathers are perceived as more generous than their childless counterparts because emotionally unstable men are more possessive and monopolize resources – traits not associated with fatherhood. Being a dad makes a man appear more “prosocial”; that is, generous and willing to cooperate.  Men are likelier to want to meet dads than childless men because fatherhood lowers expectations of inter-male competition.  It’s now established that fatherhood is linked to lower testosterone levels, especially in the first months after a baby’s birth.

There’s a lesson in research of this kind.  While parenthood generally boosts the social image of both genders, it still cripples career women more than men.  Although more fathers are taking care of the their kids while the mother goes to work, the stereotype that mothers aren’t as ambitious still hasn’t budged – in part, perhaps, because many workplaces continue to make it difficult to excel in both.  So the disappointing fact remains:  A man who prominently features a photo of himself with his children on his desk at work is doing more for his career than a woman who does the same.

*If you like this blog, click here for previous posts. If you wish, check out my new book — hot off the press! —  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.

 

 

 

 

 

 

Chocolate Lovers Review in Boston Globe!

Posted in book reviews, Chocolate Lovers, parenting, pregnancy, psychology, science by jenapincott on October 10, 2011

  A nice review for Chocolate Lovers in today’s Boston Globe

Who Thinks Pregnant Women are Sexy?

Posted in parenting, pregnancy, psychology, science, sex by jenapincott on September 26, 2011

Early one evening late in my second trimester of pregnancy, I was standing in the dairy aisle of the grocery store, with one hand on my back and the other over the kicking baby in my distended belly. A young man approached me, initiated a conversation about the World Cup, and, casually, asked me if I’d like watch the game with him that weekend. “You’re pretty!” he whispered. I was shocked.

I wasn’t putting out a sexy vibe. (Not at all.) I had assumed that any male attention I receive in late pregnancy, including that from my husband, would be friendly, not sexual. Why would a man who is not the expectant father think pregnancy is sexy? But then other women told me similar stories about how they got hit on in third trimester. So I decided to look into it, and it turns out that a study on sexual attraction to pregnancy has recently come out.

A team of Swedish and Italian doctors, led by Emmanuele Jannini and Magnus Enquist, recruited nearly 2,200 men who had joined online fetish groups such as alt.sex.fetish and alt.sex.fetish.breastmilk. They presented a questionnaire that asked the respondents questions about their preferences for pregnant and lactating women. The survey also asked for the sex and age of each sibling, and whether the sibling is a full sibling or not (half-sibling or adopted child). Most respondents reported both a pregnancy and a lactation preference. The average age at which respondents became aware of their preference was about 18 years.

What Jannini and Enquist and their colleagues were searching for was evidence that there was something special about the upbringing of men that are secually aroused by pregnancy. They knew that a specific stimulus early in life can elicit sexual behavior when that animal reaches sexual maturity. For instance, goats that are raised by sheep are sexually aroused by sheep only. This is called sexual imprinting.

Is it possible that boys that are raised by women who are pregnant for much of their childhoods are unusually attracted to pregnant women?

It turns out, what’s good for the goat is good for the guy. The more exposed a man was to his mother being pregnant and breastfeeding when he was between 1.5 and 5 years old, the more likely he is, as an adult, to be sexually attracted to pregnant and breastfeeding women.

A younger sibling is the key to early exposure. The respondents who eroticized pregnancy and breastfeeding had significantly more younger siblings than expected by chance. Respondents with one sibling were older than their sister or brother in 66 percent of cases. Interestingly, siblings born of a different mother does not appear to be related to respondents’ sexual preferences. Only a boy’s own pregnant mother seemed to leave a sexual imprint.

Freud’s “oedipal phase,” from about 3 to about 5-6 years of age, only overlaps partially with the sensitive period suggested by this study’s data, the researchers are careful to point out. Sexual imprinting is different in that it’s motivated not by sexual drive but because the individual learns what’s normal during a sensitive phase of development and later seeks sexual partners that resemble his (or her) own parents.

What does this mean for women who are pregnant or plan to be pregnant? It means you may be able to predict how attracted your partner will be to you in late pregnancy. Does he have sibling born within five years after him? If so, he’s likelier to be turned on by your pregnant self.

As for the guy I met in the dairy aisle, I’d wager he had a younger brother or sister. I’d bet more on getting this right than the winner of the next World Cup.

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, available October 11,  Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.

A Kirkus Star!

Posted in book reviews, parenting, pregnancy, science by jenapincott on September 8, 2011

Absolutely delighted that Kirkus gave “Do Chocolate Lovers Have Sweeter Babies?” a starred review. Thank you, Kirkus!
—-

Popular-science writer Pincott (Do Gentlemen Really Prefer Blondes?, 2008, etc.) provides a lively, accessible romp through the science of pregnancy.

Known for her previous research on love and sexual attraction, the author makes a natural transition in her latest. Delving into the science of pregnancy, parenthood and fetal development, she presents her findings with wit, personal anecdotes and playful humor. Eschewing predictable “avoid the shellfish” advice, Pincott provides a science-based trivia collection, drawing from studies in evolutionary psychology, biology, neuroscience, social science, epigenetics and more. She explores topics such as how a woman’s activities might influence her unborn baby’s personality, how pregnancy and motherhood can change the behavior of mothers and fathers, what factors might influence a baby’s gender and why the first hour after a baby’s birth means so much for mother-newborn bonding. Inspired by questions from her own first pregnancy, the author also digs up the answers to common inquiries such as “what does baby’s birth season predict?”; “what can Mozart really do?”; and “will what we eat now influence baby’s tastes later?” Despite the bombardment of information, Pincott presents her research as fun things to contemplate rather than additional things to worry about, so nervous expectant parents can thoroughly enjoy the book.

A fascinating supplement to the typical maternity guide.

IQ and Fish, the Whole Fish, and Nothing But the Fish

Posted in news, parenting, pregnancy, psychology, science, Sweeter Babies by jenapincott on August 30, 2011

For the nine-plus months of pregnancy, I dutifully downed fish oil pills. I had heard all about the virtues of essential fatty acids (especially DHA, docosahexaenoic acid), known collectively as omega-3s, which are found in fish such as salmon and sardines. These fats are involved in the development of new neurons and help form the cell walls — the structural support — of nerve cells. If the healthy brain is like a sponge, then the brain deprived of omega-3 is like a puddle.

Several years ago, in 2007, an enormous study funded by the National Institute of Health looked at the link between children’s scores on aptitude tests (at ages 6 months to 8 years) and their mother’s prenatal consumption of fish. It turned out that the kids whose moms ate fish more than twice weekly during pregnancy were significantly less likely to have low scores on cognitive tests. Low maternal seafood intake (two or fewer servings weekly) was also associated with increased risk of suboptimum outcomes for prosocial behavior, fine motor, communication, and social development scores. This was a huge deal. The nearly 12,000 expectant women who participated in the study were asked to record how much whole fish they ate, not fish oil supplements.

Naturally, this study — and smaller studies like it involving whole-fish consumption — inspired millions of pregnant women to focus on fish oil.

Problem is, not many of us want to or can afford to eat fish every day. Fears of mercury and PCB contamination are valid (many varieties of fish, such as tuna, have high levels that are toxic to fetuses). It’s not much of a stretch to say that fish oil pills are a better way to get your daily DHA.

But here’s the interesting part. Everyone has assumed that when it comes to omega-3 fatty acids like DHA, the source — whole fish or fish oil pills –shouldn’t matter.  Seems reasonable, but is it?

A few very recent fish oil studies cast doubt:

Results of fish oil pill supplementation range from neutral to negative…

A review of six clinical trials (1280 women in total) involving fish oil pill supplementation during breastfeeding found no significant difference in children’s neurodevelopment: language development (intelligence or problem-solving ability, psychomotor development, motor development. In child attention there was a significant difference. For child visual acuity there was no significant difference.  For language development at 12 to 24 months and at five years in child attention, weak evidence was found (one study) favouring the supplementation.

• At the Women’s and Children’s Hospital in Adelaide, Australia, researchers tracked the children of 2400 women who took DHA-rich fish oil pills in the last trimester of pregnancy. The use of these fish oil capsules compared with vegetable oil cap- sules during pregnancy did not result in improved cognitive and language development in their offspring during early childhood.

Other fish oil pill studies found disturbingly negative results:

• At the Universities of Copenhagen and Chapel Hill, researchers followed 120 Danish women who nursed their babies for four months after birth and took fish oil supplements (or olive oil pills). The children were tested in intervals up to seven years. The higher the early intake, the lower the child scored in speed of information processing, inhibitory control, and working memory tests. Boys whose mothers consumed fish oil had lower prosocial scores relative to the olive oil group.

Meanwhile, these recent studies strengthened the evidence that eating fish is brain-boosting:

• In a study that took place the Arctic, 154 11-year-old Inuit children took standardized tests for memory and verbal learning. Their scores were compared with their levels of DHA present in their cord blood at birth. Children who had higher cord plasma concentrations of DHA at birth achieved significantly higher scores on tests related to recognition memory processing. The source of DH in their mothers’ diets was fish and marine mammals. Intriguingly, the connection with higher test scores remained intact regardless of seafood-contaminant (PCB and mercury) amounts.

* A UK study of 217 nine-year-olds whose mothers had eaten oily fish in early pregnancy had a reduced risk of hyperactivity and children whose mothers had eaten fish (whether oily or non-oily) in late pregnancy had a verbal IQ that was 7.55 points higher than those whose mothers did not eat fish.

This is what I’d love to see: large studies that compare pregnant/nursing fish-eaters versus pill-poppers. Few researchers have tackled this, in part because we assume DHA works the same no matter how we get it, and because DHA from sources other than pills is difficult to measure or isolate.  Interestingly,  a study at the Norwegian Institute of Public Health compared height, weight and head circumference results of newborns whose mothers whose main source of DHA was fish versus pills.  They found that fish-eaters generally gave birth to larger babies while fish-oil-pill-poppers had newborns with a smaller head circumference.

Is it possible that fish consumption boosts IQ, but fish oil pills do not?

It’s dumbfounding, the difference in results between whole fish and fish oil. The researchers that found negative results of supplementation on nursing infants speculated on what goes wrong. It may be that early intervention with fish oil pills results in an “environmental mismatch” between prenatal and postnatal life,” (e.g. the fetus is “programmed” in the womb to live in an environment without abundant DHA and is thrown off when inundated with these fats later on).

Another theory is that the timing in these recent fish oil pill studies is off. The critical period in which fish oil may influence brain growth may be in the first trimester of pregnancy or toward the end of the first year of life — not during the time periods in which women in these studies were taking fish oil pills. It may be that DHA has a “sweet spot” — an optimum level below and above which may be detrimental to the developing brain. Indeed, when researchers look at fish oil pill supplementation and DHA-deficient premature infants, the results are much rosier.

There’s another compelling explanation of why fish oil pills don’t yield the desired results: DHA doesn’t do its magic alone. Nutrients and proteins in fish and seafood, other than DHA, may be  brain-boosters — or at least help us (and our fetuses or babies) to absorb or metabolize DHA better. All the fish oil in the sea can’t compensate for a bad diet.

In the US, a federal advisory recommends that pregnant women not eat more than two servings of fish weekly. This advice may be misguided given that fish such as salmon and sardines are high in DHA but low in mercury. Pop fish oil pills instead; they’re just as good– that’s been the message. But these recent studies point to a different truth.

Thus the case for fish, the whole fish, and nothing but the fish.

Food for thought.

*If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

Do Beautiful Babies Become the Most Beautiful Adults?

Posted in pregnancy, psychology, science by jenapincott on August 18, 2011

The Gerber baby, then and now

Forgive me, I believe my one-year-old is the cutest baby ever. Yes, yes, mothers are biased about their own children.  As I detail in my new book, certain reward circuits “light up” in parental brains only when looking at their own offspring.  But objectively — objectively! — my daughter is adorable.

The little one has “Gerber baby” features:  a bulbous forehead, big eyes, luscious cheeks and thighs (and curls). Babies with these qualities are rated as cuter than those with sunken foreheads, small eyes, and large or long chins.  Adults smile and gaze longer at them. Attractive infants are perceived to be more sociable, easier to care for, and more competent than their homely peers. They inhibit aggression in adult men. They receive more nurture.

Our baby thrills to the attention, and my husband and I have started to worry that being cute might not lead to anything good.  I have a theory that ugly ducklings and tomboys grow up to have richer inner lives.  I don’t want a princess.

We want to know:  Do the cutest babies turn out to be the most attractive adults?

Conveniently, a recent study by psychologists Gordon Gallup Jr, Marissa Hamilton, and their colleagues addresses this very question. (I love these whimsical studies; they’re motivated by genuine curiosity.) The presumption is that physical attractiveness remains stable over time.  This has been proven in childhood onward:  attractive ten-year-olds are likelier to be attractive adults.  (Another study found that adult attractiveness can be predicted as early as age five).  But until now no study had tracked attractiveness from infancy.

It’s interesting, how the psychologists went about it.   They sifted through high school yearbooks and found forty graduating seniors who featured photos of themselves as infants. Then they asked several hundred college students to rate the the individuals — in infancy and in adulthood — for attractiveness.

The upshot?

There was no correlation between attractiveness in infancy and (young) adulthood. Some ugly ducklings turned into swans, some baby swans become ugly ducks.  Some gawky, awkward babies remained that way into their senior year of high school.  And some beautiful babies kept their glow through the years. This was true of males and females alike.  Cuteness — or homeliness — in infancy does not predict future attractiveness.

The study included an interesting side finding:  While the raters were likely to agree about which infants were attractive, they often disagreed about which eighteen-year-olds made the cut. Why? The gold standard of baby beauty — the forehead, the eyes, the thighs — is universal. These preferences are hard-wired in us to elicit care and protection, while the perception of adult beauty is tempered by culture.

Cute babies are universal positives.  In this light, it’s OK that mine gets attention now.  The future will be much less predictable.

 

 *If you like this blog, click here for previous posts and here to read a description of my most recent book, Do Gentlemen Really Prefer Blondes?, on the science behind love, sex, and attraction. If you wish, check out my forthcoming book, Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy. 

 

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