Earlier, I talked about a hundred-year-old sex education book that I got at a yard sale. This is a continuation of that review. I will now discuss how he got the science of heredity wrong.
We now know that all genetic information is unchanged by anything that happens in the life of the organism*. Changes in a species come through mutation and natural selection. If the carriers of a gene have more fertile offspring, then the gene will become more common. No individual can do anything to change the genes that he or she will pass onto the next generation. Good heredity, or eugenics, means finding a mate with the best genes.
But 100 years ago, this was not common knowledge. Many people had a Lararckian idea of inheritance. They thought that things that happened in an individual's life were commonly passed on to offspring. This belief was often mystical. The author believed that children would inherit most of the physical, mental, and moral attributes of their parents.
His working definition of 'heredity', which is never stated in the book, is 'anything that happens to a child before the child is old enough to make decisions'. His definition of 'eugenics' is 'anything that improves heredity'. This is a much broader definition than the 'selective breeding' definition that we use. He talks about eugenics as something that couples can start to do even after they get married, and gives advice on what to do.
Here are some of the things that he puts in the category of 'eugenics':
1) Making sure that the father has not been using alcohol, tobacco, or drugs for a good length of time before conception
2) Making sure that the couple does not have sex unless they would welcome a child
3) Giving the mother good food and a healthy environment during pregnancy
4) Ensuring that the infant receives proper love, care, and attention
Basically, anything that we would call prenatal care or early childhood care is included in his definitions of heredity and eugenics. And the book is full of good advice that matches modern research.
He got the mechanism wrong. We now know that the developing minds of children are heavily influenced by the environment in early life. A good home environment will generally produce good kids, while a bad environment will put the child at a huge disadvantage. Kids, even ones too young to talk, can tell when they are not wanted, and that knowledge can destroy them.
But he knew nothing about the cognitive abilities of infants. He saw the connection between the behavior of parents and later success in life, and assumed that the mechanism was either mystical or biological. He thought that he was being scientific, but without a good understanding of causality and basic facts, most of what he said ended up being folk wisdom and superstition.
Sometimes folk wisdom is confirmed by scientific research. Sometimes it is not. While much of what he said was good and useful, some of it was bizarre, wrong, and possibly dangerous. I will cover that in a later review. It is always useful to read something like this with a modern eye. By spotting his mistakes and seeing where they came from, you are less likely to believe similar semi-scientific stuff produced by modern writers.
You do see hints that he was moving beyond the culture of the time. When discussing heredity, he made a passing mention of Jews, mentioning how they cared about good heredity. The implication was that they were a superior race of people. This was in a culture of chronic antisemitism.
Jews do have, on average, IQ's of about 5 points above average. I don't want to digress into a discussion of IQ as a valid measuring instrument, but it is correlated with success in life, and it is influenced both by genes and early childhood development.
And here I stumble across one of the most politically incorrect themes in science. It is almost impossible to have an intelligent conversation about human biodiversity. Liberals hate admitting that one group of people might better or worse than average in any way, and conservatives hate admitting that genetics might have a big impact on how people act, and their success in life.
The facts show that people are different for a variety of reasons, some of them genetic. The mind is affected by natural selection just like any other part of the body, and different groups of people have lived in very different environments. It shouldn't be too hard to talk about these differences, while still holding firm to a belief that all humans are valuable and deserve basic human rights and an equal chance to succeed.
But it is hard, and one of the reasons it is hard is because eugenics and talk of racial differences has a very bad connotation. People have used it as an excuse to commit some very nasty crimes. I'll mention that in a later review of this book.
* There are a few transgenerational epigenetic effects, but these don't seem to have much impact on heredity.