Intelligence as a success factor: A foray into a fascinating field of psychological research


What does it mean to be intelligent? Prof. Dr. Spinath began his lecture by stating that intelligence is a kind of success factor for one’s professional career and private path in life. “But such a definition invariably leads to misunderstandings and errors, which I would now like to dispel.” Basically, intelligence research can be said to be psychology’s “favorite child.” Thanks to a research tradition dating back more than 50 years, today’s intelligence tests are seen as reliable and valid. Often, however, findings from intelligence research give rise to socio-political controversy with ideological overtones and even interdisciplinary disputes.

Spinath negated the widespread view in our society that there are different types of intelligence. The term “intelligence” is used in an inflationary and inadmissible way in general literature, he continued, for example when talking about emotional, erotic, financial, spiritual or creative intelligence. To provide orientation as to what constitutes intelligence, he instead named factors that are among the group of cognitive abilities: linguistic comprehension, inductive and deductive reasoning, word fluency, numeracy, spatial awareness and retentiveness. Perceptual speed also plays a role, Spinath stated, since more intelligent people can solve tasks more quickly.

The often heard statement “I’m not good with figures, but I’m very eloquent!” demonstrates a further, persistent misunderstanding: people are subject to a perceptual error here, since they are comparing themselves with themselves and not with other people. While it is of course true that some people are better at some things than others, large-scale studies have shown that although the various aspects of intelligence can be measured in a differentiated way, they ultimately merge into one single meaningful overall value, the so-called intelligence quotient.

By definition, the average IQ value of the population is 100; this represents the maximum of a Gaussian normal distribution. The higher this value, the more intelligent a person and vice versa. But only two percent of the population have a very high IQ value of over 130. According to one study, there are regional differences in IQ throughout Germany in the form of west-east and south-north divides; this points to a loss of human capital in regions with high unemployment. According to Spinath, there is also an interesting connection between IQ and life expectancy: Intelligent people are more likely to live longer, because they exhibit more favorable health behavior.

Anecdotally, Spinath spoke of stereotypical stigmas concerning giftedness. How do we think of highly gifted people? Mostly as men or boys with glasses who look like the novel character Harry Potter or are loners. According to research, this is a typically German phenomenon. In other cultures, this characteristic is perceived differently: People in the USA, for example, think of giftedness above all in terms of team spirit and collaborative work, while in Asian countries it also includes wisdom and experience that gifted people contribute and pass on, to the benefit of others.

To what extent, if at all, is intelligence hereditary? Spinath dispelled two misconceptions in this context. First, the effects of predisposition and environment cannot be examined separately. And second, the influence of one’s environment becomes predominant over genetic factors throughout the course of one’s life. “Genes contribute 60 percent to a person’s intelligence, and the environment 40 percent.” This has been demonstrated in studies on twins, he continued. However, this ratio changes over the course of one’s life: In the early years, what happens within a child’s family is decisive for his or her intelligence, but this factor quickly loses significance. Already in young adulthood it plays only a marginal role, while genetic factors become increasingly important. Researchers refer to this as an active predisposition-environment correlation.

Spinath’s conclusion after more than 30 years of psychological research: “Of course, intelligence also depends on education. But we humans are and remain different. There is no such thing as genetic fate, but it takes a lot of effort to dispel this misconception.” Individual differences only become a problem, he said, when the view prevails that people must not be different. “The key to equity in education lies in acknowledging interindividual differences and in being aware of and implementing appropriate ways of dealing with them.”

Prof. Dr. Frank M. Spinath has held the Chair of Differential Psychology and Psychodiagnostics at Saarland University since 2004. As co-initiator and scientific director of the "Twin Life" study on twins in families, which has been funded since 2013 as part of the long-term program of the German Research Foundation, he is investigating the development of social inequality together with colleagues from the fields of sociology, psychology, and human genetics.

Dialog in the Museum
February 23, 2023
Mercedes-Benz Museum
70372 Stuttgart

Prof. Dr. Frank M. Spinath
Saarland University