For example human acquisition of language, can we say it is learned, but has an innate component -- because there is a particular structure of the tongue, and perhaps also a specific cognitive ability which is requisite to speaking/ learning a language.

The aforementioned requisites are ones which are reliant on genetics, thus can we say there are innate components to it, even though it is largely, based on experience, as stated in the assertion below.

"The behavior of language acquisition is based on experience, and subject to continual refinement and therefore can be classified as largely learned, however, due to the requisites it also has an innate component to it"


Think of a cake. Is a cake determined by its ingredients or by its preparation (mixing, baking, etc)? It's a meaningless question. The cake is determined by both.

Now think of two cakes. In principal, we can now begin to talk about the causes of their differences. For example, if they had identical ingredients but were prepared differently, then we could say that the differences in the resulting cakes were due to different preparation.

Humans are baked cakes. Quantitative genetics is a field which tries to estimate to which extend differences between organisms are due to genetic factors. Learned behaviors are consistently found to be heritable in quantitative genetics studies. For example, adult vocabulary size is substantially heritable. It is not that the words are literally transmitted to the offspring, but rather genes that influence the cognitive abilities, interests and personality of the individual. That vocabulary size is "heritable" means that a substantial portion of the differences between individuals' vocabulary sizes are due to genetic differences (although by no means only due to genetic differences).

In short, what I'm trying to get at, is that you can only talk about the relative contributions of genes and environment if you're talking about it in the context of differences between individuals. In that case, yes, learned behaviors have an innate component.

  • $\begingroup$ Re: vocabulary size being heritable, In the child psychiatry literature, shared environment accounts for the largest component of the variability in vocabulary size, followed by unique environment, then genetic factors. This is seen in English and Chinese. Where do you see data that "vocabulary size is substantially heritable"? $\endgroup$ – De Novo Jul 4 '18 at 16:26
  • $\begingroup$ @DanHall Nope. Shared environment accounts for nearly nothing in vocabulary size. (Once the person is entering adulthood.) $\endgroup$ – Eff Jul 4 '18 at 17:03
  • $\begingroup$ can you share your data? $\endgroup$ – De Novo Jul 4 '18 at 17:04
  • $\begingroup$ @DanHall For example, vocabulary tests are well known to load fairly highly on g, and it's well known that g has little shared environmental influence. But there are also studies that directly estimate heritability in vocabulary, see for example (van der Berg, Posthuma, Boomsma: A Longitudinal Genetic Study of Vocabulary Knowledge in Adults). $\endgroup$ – Eff Jul 4 '18 at 17:50
  • $\begingroup$ Are there in fact any (practically reachable) limits on vocabulary size? Personally, I have a good vocabulary in English (including Shakespearean and a good bit of Middle English), the technical jargon of several disciplines, and a reasonable bit of several other languages, yet previously-learned vocabulary doesn't seem to disappear when I add new. So where is the heritability? $\endgroup$ – jamesqf Jul 6 '18 at 17:18

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