Of Mice and Men (Actually: Of Rats and Dads)

August 19th, 2010 by Brian Reid

Earlier this week, Scientific American posted an absolute must-read on the way that the presence of a father changes the brain of his newborns and how — in turn — a new dad’s brain is fundamentally changed by the experience. There is a big caveat to note: the work referenced was in degu rats. But the results were interesting. When male rats were physically present — touching — their offspring, they grew new brain cells:

But the extra boost of brain cells only occurred if the mouse father stayed in the nest. In other words, if he was removed on the day of their birth, nothing happened. One new set of brain cells formed in the olfactory bulb, and were specifically tuned to the smells of his pups. Another set of neurons grew in the hippocampus, a crucial memory center in the brain, which helped to consolidate the smell of his pups into a long-term memory.

So while I certainly might have felt like a moron when I was first struggling to learn the ropes of parenting, there was actually a lot going on upstairs (if you can assume that my brain works like that of a degu rat). On the flip side, if the dad was removed from the kids, they had fewer brain connections than baby rats who got to hang with dad:

Specifically, the degu pups raised without fathers had fewer synapses in both the orbitofrontal cortex and the somatosensory cortex. Having fewer synapses can alter the way information is processed in the young animals, and would make these brain areas perform abnormally.

Of course, it’s great sport to over-extrapolate this kind of research into humans and, indeed, a number of valid criticisms are leveled in the comments to the SciAm piece. It’s not clear if human brains work the same way. It’s not clear if the family bond has anything to do with this (would non-paternal rats experience the same effect?). All of this, taken together, makes it tough to consider this a major piece of evidence suggesting that human kids are doomed without their biological father in the picture (even though the piece hints at that idea). It’s not that easy to tease apart biology, circumstance and social norms. As I’ve said before, if you have a kid in a loving and stable household, he or she will probably do well, regardless of who the other members of the household are (mom/dad/stepparent/uncle/aunt/older sibling/grandparent/etc./etc.).

That said, I’m still a sucker for evidence that suggests that having an involved dad (or father figure) does help around the margins. And this week, I got that, too. USA Today, reporting from the American Psychological Association meeting, reported that sons who had good relationships with their fathers when growing up ended up being better able to handle stress. (The article was not all that detailed, which makes me wonder if the same effect was seen with daughters … I assume not.) At any rate, if you’re a dad with a son and things are going well, you can add that to the things to feel good about.

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