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When the Brain Grows, the IQ Rises

Michael A. Woodley of Menie, PhD, Scientist in Residence at the TU Chemnitz, finds for the first time a link between increasing brain size and long-term increase in intelligence quotient

  • Michael A. Woodley of Menie, PhD, conducts interdisciplinary research into aspects of human intelligence. Photo: Steve Conrad

The average mass of the human brain has increased in Germany and the UK during the last century. This has been accompanied by gains in IQ. International scientists led by Michael A. Woodley of Menie, PhD, have now connected the two for the first time. Woodley of Menie is Scientist in Residence at the Technische Universität Chemnitz and Fellow at the Center Leo Apostel for Interdisciplinary Research at the Vrije Universiteit Brussel. David Becker, another scientist from the TU Chemnitz, also was involved, as well as researchers from Canada, Brazil, and New Zealand. Their results have been published in the January 2016 edition of the journal "Learning and Individual Differences", which is published by Elsevier.

The psychologists base their statements on secondary analysis of two datasets which represent several studies and give indications of a long-term increase of brain mass in the UK and Germany. The analysis reveals the following: for Great Britain, over a period of 80 years: among men, the mass of the brain increased by 52 grams, among women by 23 grams. In Germany, over a period of 99 years, the increase was 73.16 grams for men, and 52.27 grams for women. Based on this, the researchers led by Woodley of Menie used a method developed by the American psychologist Arthur R. Jensen to estimate IQ gains stemming from increases in brain mass: for men in the UK the increase is 0.19 IQ points per decade, for women it is 0.08 points. In Germany, the result is an increase in IQ of 0.2 points per decade for men and 0.15 points for women.

Afterwards, the scientists set these figures in relation to the estimates of the so-called Flynn effect. "One of the co-authors on the paper is Prof. Dr James Flynn, who was one of the first to detect consistently increasing IQ over time in different populations. This IQ increase was actually called the Flynn Effect in recognition of his discovery," explains Woodley of Menie. The Flynn Effect states that IQ has been steadily increased by an average of three points per decade in Western countries since the beginning of the 20th century. The current study shows that the Flynn effect can be explained in part by the growth of the brain. In Great Britain, where studies show an overall increase in IQ of 1.1 points per decade from 1932 to 2008, the contribution from increasing brain mass amounts to almost 13 percent. In Germany, where a total increase of 6.1 IQ points was found in the period from 1956 to 2008, the percentage contribution is around three percent.

The research results were published in the journal "Learning and Individual Differences": Michael A. Woodley of Menie, Mateo A. Peñaherrera, Heitor BF Fernandes, David Becker, & James R. Flynn (2016): It’s getting bigger all the time: Estimating the Flynn effect from secular brain mass increases in Britain and Germany. Learning and Individual Differences, 45, 95-100. DOI 10.1016 / j.lindif.2015.11.004

Keyword: Scientist in Residence

The "Scientist in Residence" scholarship was established at the TU Chemnitz in April 2015, allowing the university to invite visiting researchers with a worldwide reputation in order to promote academic exchange and maintain international relations. The focus is on the TU Chemnitz’ core competence "human and technology". Michael A. Woodley of Menie, Fellow at the Center Leo Apostel for Interdisciplinary Research at the Vrije Universiteit Brussel, is researching and working for two years at the university in Chemnitz within the scholarship program. Born in England with a degree from the Royal Holloway University of London, he is conducting interdisciplinary research into aspects of human intelligence as well as human capital and thereby focuses on how intelligence influences technological and economic progress.

For further information, contact Michael A. Woodley of Menie, PhD, email michael.woodley-of-menie@hrz.tu-chemnitz.de.

Katharina Thehos
16.02.2016

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