Are the most intelligent people because of their genetic inheritance?

Are the people with the best mental agility and ability to think basically because of their genes?

Everyone has wondered at one time or another whether the smartest people are whether the most intelligent people are the most intelligent because of genetic inheritance or because of the environmental influences they receive, such as the quality of nutrition or the education provided by their parents. In recent years, behavioral genetics has provided a detailed answer to this historical question.

Research in the field of differential psychology reveals that both genes and environment play a role. both genes and the environment play a very significant role in determining IQ, and that the in determining IQ, the classic measure of intelligence. However, the relevance of heredity seems to be slightly higher than that of the environment.

How is intelligence defined?

The construct "intelligence" is difficult to define, since multiple meanings have been attributed to it both in lay language and in the scientific community. It is a complex capacity that encompasses the ability to learn new information, to apply different types of reasoning and to solve problems, among many others.

A special definition is the one that has been made from the operational approach. This perspective proposes that intelligence should be defined as. "that which is measured by IQ tests", instruments that have been shown to be moderately reliable.instruments that have been shown to be moderately useful in predicting aspects such as job performance and socioeconomic status.

However, intelligence is a very broad attribute that exists not only in humans. It has been defined by many authors as the ability to behave adaptively in complex situations. The conception of intelligence as a global and stable factor stands out in this type of definitions.

Relationship between genetics and intelligence

From the field of behavioral genetics, which analyzes individual differences in behavioral aspects (such as intelligence) based on genetic methods, it is estimated that the coefficient of heritability of IQ ranges between 0.40 and 0.70. This means that approximately half of the variability is explained by hereditary factors..

Based on reviews of studies of this type, Antonio Andrés Pueyo concludes that approximately 50% of the variance in intelligence is explained by genetic causes, while the other 50% is due to various environmental factors and random measurement errors.

In general, older studies have found a greater weight of genetic inheritance in intelligence than recent research. Moreover, it seems that the heritability coefficient is higher in cases where IQ is very high (over 125) or very low (under 75).

As for the different factors that make up intelligence, some studies have found that verbal skills are inherited to a greater extent than manipulative skills. The weight of genetics in verbal IQ increases with age.The same is true for other components of intelligence, although not as markedly.

On the other hand, the fluid intelligence described by Raymond B. Cattell, a construct similar to the global ("g") factor originally used by the pioneer Charles Spearman, is more influenced by genetic inheritance than crystallized intelligence. While the former is associated with reasoning and solving new problems, the latter refers to accumulated knowledge.

Influence of brain structure and processes.

Different authors have pointed out the relevance of the physiological processes of the central nervous system in intelligence. This would involve structures and functions such as frontal lobes, gray matter density (composed of neuronal bodies, neuronal (composed of neuronal bodies, amyelinic dendrites and glia) in the brain or the metabolic rate of glucose.

Thus, Vernon wrote that the differences found in IQ tests reflect a greater speed and efficiency in the transmission of nerve impulses, while according to Eysenck the most important thing is the number of errors in these connections: If fewer transmission failures occur, the brain will consume less glucose, reducing energy expenditure.reducing energy expenditure.

Other studies have related measures of intelligence to Blood flow and neurochemical activity in the frontal lobes, as well as gray matter density. All of these morphological and functional characteristics are inherited to a significant degree, since they depend on the expression of certain genes.

Environmental factors affecting IQ

Intelligence depends to a large extent on the environment. A large number of factors are relevant in this respect, among which the following stand out access to quality nutrition, education and health care, which allow the greatest possible development of IQ potential. that allow the greatest possible development of the biological potential of each person's brain.

In many cases it is extremely difficult to determine what proportion of behavioral variability can be attributed to heredity and what to the environment, particularly when it comes to influences related to the immediate family environment. There is also a reciprocal interaction between genetics and the environment that is constantly occurring.

According to Andrés Pueyo, environmental factors explain almost half of the variance in intelligence, a weight very similar to that of genes. Within the 50% of variability that is not accounted for by heredity, he attributes to common or common variance. he attributes 30% to common or inter-familial variance and 10% to the non-shared environment.. Error variance weighs another 10% for this author.

Thus, non-shared environmental influences, which differ among people raised in the same family, seem to be more relevant in determining intelligence than the shared environment, although the weight of the latter is sufficiently high to be taken into consideration.