Inherited Learned Behavior

There is what we inherit from our parents and there is what we learn from our own experience. The two are distinct, right? Well, actually no they are not separate. This was further demonstrated by a Princeton study (Danger avoidance can be genetically encoded for four generations, biologists say):

“Moore and her colleagues investigated whether C. elegans can convey this learned avoidance behavior to their progeny. They found that when mother worms learned to avoid pathogenic P. aeruginosa, their progeny also knew to avoid the bacteria. The natural attraction of offspring to Pseudomonas was overridden even though they had never previously encountered the pathogen. Remarkably, this inherited aversive behavior lasted for four generations, but in the fifth generation the worms were once again attracted to Pseudomonas.”

This is not an entirely new understanding. Earlier research has found similar results in other species. The study that always fascinates me had to do with rodents. The scent of cherry blossoms was emitted in their cage and immediately following that the bottom of the cage was electrified. Unsurprisingly, the rodents jumped around trying to avoid the pain. The rodents learned to begin jumping merely at the presence of the scent, whether or not any electric shock followed. The interesting part is that their rodent descendants, even though never shocked, would also jump when they smelled cherry blossoms. And this lasted for multiple generations. A very specific learned behavior was passed on.

Of course, this isn’t limited to worms and rodents. Humans are harder to study, partly because of our longer lives. But researchers have been able to observe multiple living generations to discover patterns. I’m not sure if this exactly fits into learned behavior, except in how the body learns to respond to the environment. It’s similar enough. This other research found that the children and grandchildren of famine survivors had higher rates of obesity that had nothing to do wasn’t caused by genetics or diet. It is what is called epigenetics, how the genes get set for expression. The same genes can be switched on or off in numerous ways in relation to other genes.

I find that fascinating. It also makes for much complication. Almost no research ever controls for multigenerational confounding factors. Epigenetics has been largely a black box, until quite recently. To be certain that a particular behavior was directly related to specific genetics in a population, you would have to be able to follow that population for many generations. To fully control for confounders, that would require a study that lasted more than a century. It might turn out that much of what we call ‘culture’ might more correctly be explained as population-wide epigenetics.

* * *

As a side note, this would have immense significance to dietary and nutritional research. Many of the dietary changes that have happened in modern society are well within the range of epigenetic involvement. And the epigenetic effects likely would be cumulative.

We have an ongoing and uncontrolled experiment going on. No one knows the long-term consequences of the modern industrial diet of refined carbohydrates, added sugars, highly processed vegetable oils, food additives, farm chemicals, microplastic, etc. It’s a mass experiment and the subjects never chose to participate.

Definitely, we have reasons to be concerned. Francis M. Pottenger Jr. studied the dietary impact on feline health. He fed some cats a raw food diet, others a cooked food diet, and a third group with a diet mixed of raw and cooked. The cats on the cooked food diet became sickly in the first generation and were entirely infertile after a number of generations.

This is not exactly similar to the human diet of industrial foods. But it points to how results play out across generations. The worst effects aren’t necessarily seen in the immediate generation(s). It’s future generations that have to deal with what those before them caused, as true for epigenetics as it is for national debt and environmental destruction.

8 thoughts on “Inherited Learned Behavior

    • Basically, that post is an argument from ignorance. Since we know so little, therefore we should dismiss it. Whatever… That seems counter-productive. If all preliminary research was dismissed, we’d have no new discoveries. My point is that the assumption of any influence, including genetics and environment, is pleading from ignorance until we have studies that last more than a century.

      The epigenetic research doesn’t prove anything as much as it challenges the entire edifice of our cultural worldview of isolated individualism, social Darwinism, and genetic determinism (and also the race realism popular among HBDers). Genetics research, for example, has been an amazing failure for all the funding that has gone to it. All the genes that have been associated with obesity still barely might explain a small fraction of the cause of obesity. Yet genetic determinism has practically become the dominant ideology of our society. Based on what? Very little.

      Genetics is usually assumed to be the cause in study results, even when environmental and epigenetic factors were never controlled for, much less even mentioned. It is the default conclusion that doesn’t have to be proved, according to its adherents. Most of what genetics research has found is correlations and they’ve struggled to prove causation in most cases. But it’s easy when data mining large data sets to find all kinds of correlations.

      The fact of the matter is multiple fields of study right now are in the middle of a replication crisis. To perceive epigenetics research as unique is beyond naive. What epigenetics research shows us isn’t necessarily what we know. Rather, it indicates how little we know. That was the point of my above post. Future generations will be amused by our era’s overly confident hubris about what we think we know.

    • Consider the twin research. It is held up as some of the strongest evidence of genetic determinism. Yet it is some of the worst research around.

      Even if it wasn’t such pathetically weak evidence for some cause or another, there is zero reason to assume it is genetics. Twins also share epigenetics and typically share environment as well. Even twins adopted to separate families tend to be adopted by similar families that raise the twins under similar conditions.

      So, why does this kind of indefensible genetics research rarely get the same scrutiny as epigenetics research? It’s simply that one conforms to cultural and ideological biases, whereas the other doesn’t. I’m not arguing, therefore, we shouldn’t research genetics. But I am a fan of equal treatment, if we hope to discern what is true, however long it takes.

      Why such dismissiveness of epigenetics research? Why such fear of the challenge it poses to the dominant paradigm of our society? No one needs to argue that present epigenetics research has absolutely proven anything in order to argue that it justifies serious consideration and further research. As with genetics, proving causation is difficult. But that never stopped genetic researchers or their defenders.

      The doubts and questions posed by the possibility of epigenetics are profoundly challenging. Just the possibility, as indicated by a wide variety of evidence. Why not put all possibilities on the table and research them all without assuming one must be true in advance? Below is the type of thing that could be explained by epigenetics… maybe not but then again maybe so. Nobody knows. That collective state of ignorance should pique our curiosity, rather than shut down debate.

      It’s strange and intriguing. My response to such things is curiosity. Genetics can offer almost nothing with explanatory power for such things. And even ‘culture’ is such a hazy and broad-sweeping concept. What kind of effect, physiological or psychological, can be observed across generations and centuries? In the failure of conventional theories to account for all of the evidence, maybe it is time to consider alternative theories. This is particularly true considering the mass misunderstanding about the scientific difference between heritability and inheritance.

    • Here is what I was thinking about in terms of genetics research on obesity, a passage from Tim Spector’s book Identically Different:

      “Until three years ago I was one of the many scientists who took the gene-centric view of the universe for granted. I had spent the last 17 years producing hundreds of twin studies trying to convince a sceptical public and scientific world that virtually every trait and disease had a major genetic influence. My colleagues and I around the world were largely successful in this, and the prospect of finding the genes underlying most diseases looked increasingly certain. But I had a nagging doubt that we were missing something. [ . . . ]

      “However, despite the extensive list of successes, a few signs were emerging that the paradigm was wrong. Most of the gene discoveries for common diseases turned out to be interesting in terms of biology, but the more we discovered the less useful each new gene became in accounting for the disease, since each gene is of tiny individual effect. For example, the 30 or so genes discovered for obesity, even when combined, account for only 2 per cent of the disease.

      “This was frustrating to all of us working in the field, as it meant that each common disease was contolled not by one gene but by hundreds or even thousands of genes. This would require teams from many countries to combine forces and perform studies of tens, and sometimes hundreds of thousands, of subjects in order to find these tiny effects. Another consequence was that for common diseases (unlike rare monogenic diseases) these gene tests were pretty useless for prediction [ . . . ]

      “While hundreds of recent gene discoveries have given us great insights into new disease mechanisms and possible drug targets, the common genes found to date usually account only for less than 5 per cent of the genetic influence. Exactly where the missing 95 per cent comes from is a mystery that is perplexing the field. Most scientists agree that we simply aren’t smart enough to realize what we don’t know. [ . . . ]

      “There are few if any examples of environmental factors without a genetic component, and conversely genes don’t work alone and are usually dependent on the cells they live in and their environments. So in a world where hundreds of genes are working together to influence a trait or disease, the old distinction between nature and nurture is simply no longer relevant.”

    • Here is something else about genetics from David Shenk’s The Genius in All of Us:

      “In other words, there’s nothing wrong with the twin studies themselves. What’s wrong is associating them with the word “heritability,” which, as Patrick Bateson says, conveys “the extraordinary assumption that genetic and environmental influences are independent of one another and do not interact. That assumption is clearly wrong.” In the end, by parroting a strict “nature vs. nurture” sensibility, heritability estimates are statistical phantoms; they detect something in populations that simply does not exist in actual biology. It’s as if someone tried to determine what percentage of the brilliance of King Lear comes from adjectives. Just because there are fancy methods available for inferring distinct numbers doesn’t mean that those numbers have the meaning that some would wish for.”

      If the old dualistic paradigm no longer makes sense of the data, if human biology is much more complex than we previously acknowledged, so much of what may have seemed absurd and disproven might need to be reconsidered. We are obviously inheriting so much by pathways that cannot be genetic. So, what exactly is the causal mechanism? But to attempt to answer that, we would first have to admit that we’ve been wrong about so much and that even now our ignorance is immense.

    • All of that said, epigenetics might end up being a lot less impressive than some of the conclusions based on the research so far. I don’t doubt that much will be proven wrong in multiple areas of research.

      So, criticisms are relevant and invited. But I’m a radical skeptic who is skeptical of what I perceive as ideological-driven pseudo-skepticism, even as I acknowledge my perceptions could be wrong.

      Still, I’ll remain skeptical of the status quo, until evidence indicates otherwise. I’ll change my mind if somehow the dominant paradigm proves correct, not that I’m going to hold my breath.

    • I decided to look more closely at that blog you linked. I noticed the blogger, Jerry Coyne, is a race realist.

      To my mind, that makes him highly suspect. I’ve come to the conclusion that there is no meaningful distinction between a race realist and a racist.

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