Of course. If we think about language, nobody is going to argue that to speak a language is related to genetic factors. But genetic factors or other accidents as the attack of a virus can cause a damage to the brain, and put a limit to the learning of language. There exist more factors in the development of intelligence, like an extreme situation of limited maternal care. In some hospices with many children and lack of nurses to attend a great number of babies, almost 100% were suffering of extreme mental retardation. Thus the mentioned scarce care would result in a very limited or retarded body mobility as well an extreme retard in language learning. Some hospices had demonstrated that a serious scarcity of maternal care can be fatal for the development of intelligence. But this extreme lack of care, it does not occur only in some hospices. In some families it also occurs for similar reasons; some babies and children can suffer a similar retardation of their intelligence. As in general the most poor people can be in such a situation, it is not a miracle the children of poor people would have a lower knowledge of the local language. Thus if making a test of intelligence among children, the children of the most poor families, or mothers, would have a much lower IQ than common children of the same age. Some would show such a dramatic low level of intelligence that nobody is going to pass them a test.
I postulate that the test of IQ is simply a test of language. The application of the test consist in asking a number of questions to children. The children should understand the question presented to them, and should be able to answer the questions properly. If the child do not understand the question, or do no know to answer or give a wrong answer it results in a negative point.
Other test are merely derivate of the language. Like the test of progressive matrices. For a child to be able to answer a test of progressive matrices he must understand the language, as most of the items on the test are related to numbers or other logical concepts. Logical concepts and number concepts can only be learned by a mediation of language. If the language training of a child is very poor or scarce, there is a dubious probability that the child could understand the logic of those progressive items.
Making it simply, intelligence is prove by the use of language. How fluid and ample it is for a giving age of a child or a youngster. Even we have an idea of the intelligence of someone by the ability he has with the language.
In general, only poverty or extreme poverty can be condition related to a deprived intelligence. The intelligence of children is also related to the intelligence of the mother, natural mother, or surrogate mother. The intelligence of a child is the result of some work of his his real or surrogate mother. If the real or surrogate mother do not work on the child language learning, the child can eventually be able to speak a few words. But a few words is what a mental retarded is able to speak.
I postulate that a child starts to get confident with some words, when he had heard them on average some 500 or more times. The easier words (shorter) can be learned first. After a time and after hearing some 10 or 20 millions words the baby began to speak the most common and shorter words. I had my granddaughter of 20 months this morning to put her some videos on the computer. The computer was switched off and she said, switch on the computer. I did it and then when it appeared the window asking for the password, she said, write the password. He did not invented these words. I had said a number of times, I must switch on the computer. And I had also said, now, I must write the password. So he heard those words, and she is repeating them. The language is an imitation. You cannot imitate a language unless you hear it first. I am putting her some videos with songs in English. Then I am commenting in Spanish and English, to make her learn English as well. She is a little in retard with English, but she is also saying words already.
When we are going upstairs, I start to count the stairs in English and she follows the counting. Sometimes she jumps up a number. But it is already counting both in Spanish and English. Not yet a perfect counting. Sometimes he commits some errors. This is quite normal. Three days ago she said something I did not understand well. Then, as she was pulling me by the hand to go to the garden, that had some exotic trees and bamboos. I realized she was saying “lets go to the forest”. She had heard a video about some characters going through a forest. As the words forest repeated a number of times, she had learn it. This took me by surprise. By the way, she said not this in English but in Spanish. She is not so advanced in English yet. She said something like “wrme wrm ‘amos x la selva.” I could not get the meaning at first, but she pointed to the garden saying “la selva, vamos a la selva.” I was amazed, for she is starting these days to say sentences with more than three or four words. Like three days ago, the bottoms of my cardigan. We were amazed that she said this.
I am convinced that the intelligence is synonymous of language and language is something learned. It is absurd to postulate the genes to speak a language.
A similar case is to play the piano. It is absurd to postulate the genes to explain someone playing the piano.