In a recent paper in Nature Neuroscience, Dias and Ressler trained mice to fear the smell of acetophenone. They claim that this reaction was passed on to their offspring, and to the following generation.
I don’t believe a word of it. It would require a mechanism that takes the epigenetic states of genes in the brain, sends that information down to the testes, and then somehow imprints it on the germ cell precursors. And it would have to do this in a very special way, because many epigenetic changes that are the product of learning wouldn’t be the right thing at all during embryogenesis and development: somehow you’d have to pass timing information as well – info that says “methylate this sucker when you’re three weeks old, but not before”. Genes are like a recipe, but this patch would be more like a program. And it’d take a tnuctipun – or better – to prepare it.
According to the blurb at Nature, Kerry Ressler is a neurobiologist and psychiatrist at Emory University. In other words, he’s already a good deal more likely than average to be a flake. He became “interested in epigenetic inheritance after working with poor people living in inner cities, where cycles of drug addiction, neuropsychiatric illness and other problems often seem to recur in parents and their children. So he’s motivated. He’d like this to be true. Too bad.
We’re going to see more and more articles like this: people want to hear it. Tyler Cowen certainly does, but then he may not really be people. None of this research will ever be replicated by anyone careful and honest, but that has hardly stopped a flood of analogous nonsense in the social sciences – for example, how poverty reduces your IQ, unless your name is Abel or Ramanujan.
If the progress of Science were inevitable and unstoppable, I wouldn’t worry, but that is not the case in the human sciences. Look at mental illness, where Freudians supplanted people who were at least trying to figure things out. Look at archaeology, which progressed from halfway accurate ideas about European prehistory to pots-not-people: if we just click our heels together, we can make past violence disappear.
There are more things yet to be discovered than are dreamt of in our philosophy – but there’s even more bullshit. And that’s what this is.