Okay, that title’s not especially politically correct. I think the rest of my post is, though, so humor me. Household abuse is an interesting topic to apply neuroscience to, and I found a nifty article on the subject! It even ties into our drawn-out Nature vs. Nurture debate. So you don’t have to read it yourself, here’s a synopsis:
There were startling statistics. 20,000 annual deaths in the US from homicide and 4.2 violent crimes/100 people per year. Ouch. Seems like it’s gone down a bit since then (then being 1999, since you’re not reading the article), which is probably a good sign. Same ballpark, though.
34% of “risk of violence self-reported by community residents” stems from substance abuse, and apparently a lot of that is alcohol. Type 2 alcholism is the cause. I did a bit of extra research, and apparently Type 2 is characterized by an antisocial personality disorder, are likely become alcoholics at a relatively young age, are generally male, and are thought to be influenced (either genetically or culturally) by their fathers. Nature vs. nurture indeed! Consistent with that, children abused by their parents have a 33% chance of becoming abusers themselves. Judith Harris, your theory is not entirely supported by this statistic. Epigenetically, Fetal Alcohol Syndrome contributes to violence in adulthood, as does early maternal rejection.
Serotonin plays a role in regulating aggressive behavior, which I expect you guys know. What’s a bit more subtle is that a serotonin synthesis-rate-lowering gene (tryptophan hydroxylase genotype) is correlated with higher levels of aggression. That means that low serotonin levels (however they’re created) are a major risk factor for violence (and abuse).
The article also discusses the role of the hippocampus and amygdala (smaller hippocampus, bigger amygdala = fury) and the prefrontal cortex (lower glucose metabolism in murderers). They conclude, though, that there are two different things that tend to contribute to violence: rearing environment or morphological dysfunction.
Oh snap. The answer to Nature vs. Nurture here isn’t “both,” it seems to be “either!” Which isn’t to say that they wouldn’t have additive effect; it just seems that either is sufficient for the exigent behavior. Go figure.
On Psychology and Neuroscience 
Okay first of all I’ve been singing..”It’s a hard-knock life” all morning.. you know from Annie. That probably says something about my week.
Second… is it inconsistent with Harris? We are talking abnormal circumstances….should that be factored in?
My favorite part of your entry: “smaller hippocampus, bigger amygdala = fury”! 🙂
LikeLike
I just wrote a really long post which I then deleted because it was really rambling. Probably because it’s late. What I ended up saying is that I don’t think it’s wholly inconsistent with Harris’ argument on the whole (because she DOES make provision for parental genetic and early development influence), but I do feel like it contradicts aspects of her conclusion – that parents’ role in teens’ development is less important than that of peer groups.
I think any evidence that can point to a genetic or early developmental factor determining a child’s behavior makes the role of the parent in early life harder to tease out from all subsequent adolescent peer interactions in terms of their relative impacts on a child’s future. I think that impacts her thesis.
LikeLike
Interesting! I wrote my first paper on the effects of stress, and one of them is degeneration of neurons in the hippocampus.
Stress=smaller hippocampus +bigger amygdala –> fury?
Maybe I’m overgeneralizing…
LikeLike