Are Generational Gains In Measure Intelligence Due More To Factors Related To (1) Heredity, (2) Environment, (3) Some Combination Of Both, Or (4) Other Phenomena?

Generational Gains In Measure Intelligence

Higher Iqs

    Rise in IQs has been explained through a study that was done by James R. Flynn in 1984. This study gave evidence on the increase of amounts of intelligence over time and was referred as Flynn Effect. In this essay I will examine generation gains in IQ in relation to heredity and environment or both environment and heredity. I will also source other phenomena that may be the cause of generation increase in intelligence.


     Heredity is perceived to be the mathematical estimate to indicate the amount of traits variation in a given population that can be ascribed to genes. The estimations about the heredity of intelligence vary according to the methods employed. Trahan et al., (2015) asserts that gains in the amount of IQ result due to increase in random mating which he referred to as heterosis. This phenomenon causes the production of change in traits governed by the inclusion of dominant and recessive alleles. The Flynn effect in the entire Europe reflects the effects that were in United States regardless of there being an evidence of less migrations to Europe prior to 1950 and few internal mating in between the natives and the immigrants since then.

Environment Factors

     The IQ of a certain generation is determined by a mixture of nature and nurture. Increase in the intelligence quotient shows how environment influences the cognitive abilities. Flynn effect is concerned with the non-g variance which is different to some cognitive capabilities. Culture and the environment that one is brought up in influences what forms of intelligence that will be taught, put on spotlights and nurtured. Increase in amount of IQ have also been associated with changes in socioenvironmental sector in the developing countries. The Flynn effect has served as a reminder that when people are given opportunities to prosper, more people will prosper. Cohen et al., (2013) says that from the time of pre-industrial revolution especially on the emphasis that was put on culture of reading, abstract reasoning, writing and scientific thinking. These environments have been advancing daily and this has also led to increase in IQ.

Environment and Heredity

     According Pietschnig and Voracek (2015), Heredity does not show to what extent does genes influence a single person’s traits. Due to this, heredity is dependent on how similar is the environment for a certain group of people. Even under high heredity, environment can influence the functioning of a trait. Studies done on adoption suggests that children who are adopted will after some time show some similarity in the IQ adopted them. heredity is very much dependent on the environment, adopted children who are brought up together show similar IQ than siblings brought up apart. Also identical twins reared in similar environment will have similar IQ than identical twins brought up in different environments.

     The Flynn effect suggests that, the IQ tests in industrialized countries has improved over time. This has been related to improved environment and not heredity. This is because the gene pool of the world cannot change in such a drastic speed.

Other Factors

     Different social multipliers have been proposed to support the Flynn effect. The factors include increase in nutrition, heterosis, increased scientific education, video games, modernization, complexity in TV Shows and many more advances in technology.

      In conclusion, technology development and environmental factors have been the key players towards today intelligence gains. These two factors have been advancing over a long period of time and their advancement has led to consequential increase in IQ.


Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains: A formal meta-analysis of

     the Flynn effect (1909–2013). Perspectives on Psychological Science, 10(3), 282-306.

Trahan, L. H., Stuebing, K. K., Fletcher, J. M., & Hiscock, M. (2014). The Flynn effect: A meta-

     analysis. Psychological bulletin, 140(5), 1332.

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    … & Cohen, A. (2015). GBD 2013 Risk Factors Collaborators. Global, regional, and national.

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        metabolic risks or clusters of risks in 188 countries, 1990-2013: a systematic analysis for

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