Sunday, March 27, 2011

Sticks and stones may break your bones but words will break your brain

“Sticks and stones may break my bones but words will never hurt me.” Sounds familiar? You may have been taught this witty maxim to fend off bullies during the glorious years that are high school. Since then, bullying has become a big deal: its often-devastating consequences are more than ever in the public eye. We already know that childhood abuse in many different forms (sexual abuse, physical abuse, witnessing domestic violence) can have long-lasting impacts. For example, sufferers are found to be more susceptible to depression and suicide, and more likely to engage in fights, do drugs and use a weapon. But what about verbal abuse from peers?

To evaluate the effects of peer verbal abuse on the brain and behavior, a team of researchers studied over 800 young adults who had no history of any of the big confounding factors such as exposure to domestic violence, sexual abuse, or physical abuse. The participants were asked to fill out surveys about how much verbal abuse they experienced from peers at school as well as surveys with more general questions about mood, behavior and psychiatric symptoms.

The results show that the more peer verbal abuse one is exposed to during school, the more likely they are to experience anxiety, depression, anger and drug use. As it turns out, verbal abuse from peers is just as bad as verbal abuse from parents in generating these consequences. As well, researchers found that peer verbal abuse that occurs during middle school years (ages 11-14) has the most significant impact (compared with elementary school and high school). I find that surprising, as I remember high school being much worse than middle school, but apparently it has to do with the timeline of brain development, not my personal feelings about high school.

To dig a little deeper, the researchers selected 63 participants who had experienced varying degrees of peer verbal abuse and had them undergo a brain scan (MRI). They found that participants who had been exposed to a lot of peer verbal abuse displayed abnormalities in their corpus callosum, a big bunch of white matter fibers that connect the left and right sides of your brain. The researchers suggest that this abnormality may explain some of the behaviors and symptoms associated with the abuse (such as depression).

While this study convincingly highlights the impact of bullying on the brain and brain function, there are a few things to keep in mind. Repeat after me: correlation does not mean causation. That undergoing bullying is associated with abnormalities in the brain does not mean that bullying necessarily caused these abnormalities. More studies will be needed to uncover that link. As well, the study is retrospective, meaning the authors “go back in time” by asking the participants to remember events from years ago. This can sometimes lead to faulty recalls or false associations. Lastly, I find it a bit strange that the researchers have not looked at the hippocampus of the participants. You may remember that the hippocampus is a brain region important for memory, but it is also involved in emotions, and it has been shown to be susceptible to other forms of abuse. I’m hoping the bullying-hippocampus link will be looked at in a future study.

Overall, though, the study reminds us that bullying is an important and potent childhood stressor. Sticks and stones it is.

Reference: Hurtful words: association of exposure to peer verbal abuse with elevated psychiatric symptom scores and corpus callosum abnormalities. (2010) Teicher MH et al. Am J Psychiatry 167(12):1464-71.

Monday, March 21, 2011

Who are you?

It's Scientific Chick's blogiversary! To celebrate two years of sciency goodness, treat yourself to some cupcakes:

I also take this occasion to launch my first-ever "Who are you?" thread. Since I've started this blog, I've been picking science articles that I thought were interesting, and writing about them in hopes that my excitement for science would be contagious. Two years later, it's time for me to think about how to make Scientific Chick better, and how to cater to my readers. This means I need to get to know you! So pretty please, indulge me by answering these easy questions in the comments:

1) Tell me about you. Who are you? Why are you here? Do you have a background in science? An inquisitive mind?

2) Tell me about what you like. What are your favorite stories? What topics are you most interested in? Do you enjoy a meatier science discussion, or are you satisfied with the big picture?

3) Tell someone you know about Scientific Chick. Do you have a friend or family member who you think would enjoy this blog? Let them know! Readership keeps me going. :)

Don't be shy! I can't wait to meet you!

Monday, March 7, 2011

The stress of having an unattractive partner

Here’s how blog writing usually goes for me: I peruse science journals for a suitable story, read a few articles, pick one, write the blog post, copy the reference, and find a good picture. Then I spend anywhere from an hour to a couple of days trying to come up with a title. For some reason, finding the right title is always the hardest part. So this week, when I saw an article with a title that I could use as is for the blog post, I just knew I had to write about it.

The article, as you can infer from the title of this post, looks into the relationship between attractiveness of a mating partner and stress in female birds. Most birds, like humans, tend to form monogamous pair bonds that last through the course of at least one reproductive event. Because of this “socially monogamous” system, if there are approximately the same amount of males and females around, most birds will be able to find a partner, but inevitably, a big chunk of females will end up paired with males of “below-average” quality (but I’m sure they have lovely personalities). So the researchers wanted to know, how does that make the female birds feel?

As I’m sure you can imagine, rating the attractiveness of one bird over another is no easy feat for human scientists. What’s more, beauty is in the eye of the beholder, but you can’t send out mass emails to female finches to fill out online in their spare time (“On a scale of 1 to 7, 1 being Dwight Schrute and 7 being George Clooney, how would you rate Mr. John Finchy?”). Therein lies the beauty of this study: the researchers picked a very creative model to answer their question. They studied a type of finch that comes in two colors: red heads and black heads. Even though they are the same species, red-headed and black-headed finches are partially genetically incompatible (meaning they have a harder time producing offspring), and so these birds tend to have a preference for mating partners with the head color that matches their own (though if there are slim pickings, they will mate with a bird of the other color). Knowing this, the researchers set up an aviary with a whole mix of these birds (males, females, in combinations of red heads and black heads) that had not previously met, waited until every bird had paired off, and then assessed the females’ satisfaction with their mating partner based on two parameters: how long until she would agree to breed, and how much corticosterone (a stress hormone) she had in her blood (don’t worry, a harmless procedure).

The results show that females that paired with a male of the wrong color laid eggs nearly one month later that the females paired with a male of the same head color. What’s more, females paired with incompatible (“below-average” quality) males had three to four times more stress hormones in their bloods, and this went on for weeks. Who knew that attractiveness could have such an impact on stress levels?

As it turns out, a widespread strategy used by female birds to deal with unattractive mates is to… select alternative, extrapair fathers for their offspring. Dan Savage would have a field day if he knew about these little sneaky females…

Constrained mate choice in social monogamy and the stress of having an unattractive partner. (2011) Griffith SC et al. Proc. R. Soc. B [Epub ahead of print].

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