Are some friends better for your grades than others?

This feels a little odd, but maybe not. A researcher has found that high school GPA is related to the proportion of friends a kid has who go to the same school. But the comments by the researcher are odd.

This is partially because in-school friends are more likely to be achievement-oriented and share and support school-related activities, including studying, because they are all in the same environment.

I'd say the out-side school friends are of two kinds, those in different schools and those not in any school. For the first group, why would going to the same school rather than a different school make a kid more or less achievement oriented? Wouldn't each school then be more achievement oriented than the other?

For friends who are still in school compared with those who are not in any school, whether because they're older or because they have dropped out, you would expect this result because of engagement.

But I think this guy did his research in gifted programs. I know some schools where you'd have to search to find achievement oriented kids.

So I don't doubt that the researcher got his data right and so on, but I also doubt that it tells a parent anything about how to raise their kid.

Why adolescents are crazy: part 2

I've written before about how adolescent brains differ from younger and older brains and how that affects behavior. Another group of researchers has found another difference.

Our results raise the hypothesis that these risky behaviors, such as experimenting with drugs or having unsafe sex, are actually driven by over activity in the mesolimbic dopamine system, a system which appears to be the final pathway to all addictions, in the adolescent brain.

The study had people from 8 to 30 classify images into two categories and paid them when they got it right.

Researchers measured so-called positive prediction error signals in the participants' brains  (or the difference between an expected outcome of an action and the actual outcome) as the participants discovered the results of their answers and the size of their rewards.

 "Learning seems to rely on prediction error because if the world is exactly as you expected it to be, there is nothing new to learn, " Poldrack said. Previous research has shown that the dopamine system in the brain is directly responsive to prediction errors. 

In other words, teenagers had the highest spikes in prediction error signals, so they probably had the biggest  spike in dopamine.

I don't doubt that all these researchers have identified biological correlates to teenage weirdness. On principle I doubt that any has found the sole cause. Everything is more complicated than you think it is.

Effects of high-quality child care persist into high school

Oh, boy, the new Child Development is out, but their website won't give me access to the full articles, for some reason, though I'm logged in, so I have to rely on Eurekalert's reporting.

The first article uses the  NICHD Study of Early Child Care and Youth Development to track the effects of child care to age 15. They found modest improvements in academics and behavior in kids who were in high-quality care compared with lower-quality care, and kids who spent the most time in any kind of child care self-reported more impulsiveness and risk taking at 15. "High-quality care was characterized by the caregivers' warmth, support, and cognitive stimulation of the children under their care."

The study's findings were consistent among boys as well as girls. In addition, previous studies had suggested that child care could have benefits for children from economically disadvantaged homes. So the researchers created a risk index with such factors as family income, the mother's level of education, and mothers' reports of depression symptoms, dividing their group into three based on risk. Both the achievement and behavior patterns they had found were consistent across all three groups.

In other words, the kinds of effects child care and high-quality child care have been shown to have at 4 or 5 continue at least through age 15. Because it is a tenet of my child-development world view that kids with  poor, uneducated, or depressed moms benefit more from high-quality child care than others, I would expect the effects to be greater among those kids, but they weren't, which means I will need to rethink some policy positions that follow from that. That's the bad part about believing in evidence. You have to keep rethinking things.

This just in: boys talk to their parents less than girls

When it comes to talking to parents about most dating issues, teen girls tend to disclose more than boys, and both sexes generally prefer to talk to their mothers.

 Oh, yes, yes, yes. Obvious, but obviously true. Not that girls are always candid, especially about sex and especially with their dad, but boys almost never are candid and forthcoming.

Adolescent risk taking

One school of thought for why adolescents take crazy risks is "late maturation of brain functions known as executive cognitive functions, which control impulsivity. One of these functions, called working memory, does not fully mature until the third decade of life."

This study looked at working memory and impulsiveness and found that kids scoring high on impulsiveness were more likely to take risks like fighting, gambling, and using alcohol than kids who scored low, but the type of impulsiveness varied. Kids with better working memory (smart kids) "exhibited more sensation-seeking behavior, while those with poor working memory scored higher on measures of acting without thinking."