Sandy G at The Mouse Trap reviews my earlier post on how parents’ stress can affect their children in a posting entitled Stress contagion: from parents to the child? It’s a thoughtful response — thanks, Sandy G. And there’s lots more interesting stuff at The Mouse Trap to check out for our readers. I especially enjoyed a rambling, but incredibly engaging piece, Catch 22: Psychosis, Culture and the Mind Wars; it’s a great read with so many fruitful tangential thoughts that I may have to come back and post on it again.

Sandy G. does a nice job of summarizing the four channels I suggest might be operative in transmitting stress effects to children from their parents. I think he unfairly dismisses the ‘other communication channels’ (#3); there’s some evidence, including even cross-species effects, that there are ways we affect each other’s emotional states that are not imitation and ‘chameleon’ effects. I give the example of pheromones, but that’s not the only way that this could happen. But, fair enough, Sandy doesn’t think it’s plausible, I do. The evidence is hardly conclusive so this kind of disagreement is exactly the sort of thing we need to inspire new research (‘SandyG laughed at my theories… wahahahaha, this will show him!’).

But this paragraph, I do take some issue with:

Being an anthropologist he has overlooked the genetic aspect. What if some underlying gene which endows the parent to feel more stressed is also responsible for the children being more susceptible to illness/ having more auto-immune response. After all the stress system and immune system are very much cloistered together. It is not hard to imagine that a gene that causes vulnerability to stress( or felling stressed) also increases sensitivity to environmental pathogens and sensitivity of immune response. As the child is sharing 50 % of the gene of the parent, there is a great likelihood that the sensitivity to stress and sensitivity to pathogens may be inherited in the same manner. Food for thought.

‘Being an anthropologist’?! Au contraire, Mr. SandyG! Don’t take Daniel and I as typical of our species. You will find a number of anthropologists are as quick on the ‘it’s genetic’ button as any scientists out there. Of course, SandyG is correct that there are some anthropologist who absolutely refuse to push the same button unless tied to a radiator and subjected to around-the-clock twin studies.

No, I think the point is worth making. Daniel and I are not opposed to thinking about genes. In fact, we both think about genes a LOT; I’m extremely interested, for example, in genetic expression in muscle tissue. It’s just that we think the ‘it’s genetic’ argument is sometimes not actually grounded in an understanding of how genes work or any evidence of a genetic mechanism. Sometimes — not always — the ‘it’s genetic’ argument is made in the absence of 1) evidence of a gene, 2) evidence of non-genetic causes that are as plausible or more so, and 3) any plausible biological mechanism that might link a ‘gene’ to the effect, especially in arguments about genes and behavior. So, yes, we are likely to hold off hitting the ‘it’s genetic’ button, not because we are opposed to genes; that’s like being opposed to gravity. We (or maybe it’s just me) think that, among other problems, the ‘it’s genetic’ is the instant beginning and end of the argument, and is seldom followed up with appropriate research.

For example, the observation that twins seem to be similar body-size, that there is a pattern of twins either both being thin or both being fat (and I’m not entirely sure that there is this pattern), for some people is enough to say ‘it’s genetic.’ It seems to me that this is just the beginning of the hard yards that would need to be done to demonstrate that there was a genetic cause body size, or any other trait. As Jonathan Marks has suggested in his work, a genetic argument in the absence of genetic evidence is a research hypothesis, not a satisfactory explanation. It’s the beginning of the research, not the end.

Sandy G. is probably right. There are likely some genetic traits which affect how our bodies respond to stress. These complex psychobiological processes need all sorts of chemicals and reactions in the body, so the likelihood of their being genes that affect different steps of the stress process is extremely high (I think it’s inevitable). So, yes, I agree, reactions to stress include the strong likelihood that different genes affect how susceptible people are to stressors.

However, the original study that I was consulting was poorly designed to isolate the effect of genetic inheritance as it charted families longitudinally, finding that periods of stress in the parents corresponded to periods of illness in their children. That is, much of the research held constant the genetic component of this by studying the same families over time, looking not at a whole family’s susceptibility to stress (a good experiment in itself and likely out there in some form or another), but rather at how the same families vary over time depending on their situation.

So although I agree with Sandy G. in principle, and I’m very glad he’s out there making sure that I don’t give short shrift to the evidence of genetic inheritance, I’m going to stand by my original four possibilities due to the way the research design focused on the effect of parents’ stress over time. And I’ll reiterate: I’m not opposed to genetic research and explanations; I’m opposed to ‘genetic conclusions’ without evidence or research. I feel like, in the current popular climate, we’re too likely as a society to toss out ‘it’s genetic’ when the evidence is not there. That’s not to say that genetic causes can’t exist, only that we should actually work to investigate them.