Mathematicians have different brains

Are there gender differences in the brain?

In a nutshell

Essentialism: This is what scientists call the assumption that social categories are biologically founded and therefore largely robust against, for example, situational influences. In the gender debate, this often leads to differences between men and women being viewed as "natural" characteristics.

Meta-analysis: Meta-analyzes are overview studies that summarize and statistically evaluate many papers on a topic. With their help, more reliable statements can often be made on the respective research question than a single investigation would allow.

Even today, men and women are often exposed to different learning environments, for example due to the respective study and career choices. In adults, it is therefore hardly possible to determine where a discovered neuronal difference comes from - from genes or from the environment. Rather, we are always shaped by a close interplay of the two.

Great scope for interpretation

The widespread separation between innate, biologically determined characteristics on the one hand and social imprinting on the other is therefore very difficult to apply to results from brain research. Both aspects are interwoven in many ways. This raises the exciting question: What do findings about gender-specific peculiarities actually say?

"With imaging methods, primarily where questions can be answered," explains the sociologist of science Hanna Fitsch from the TU Berlin. She has been dealing with the informative value of functional magnetic resonance imaging (fMRI) for years. "The main aim of this research is to localize and map certain mental phenomena. However, such investigations alone cannot answer questions about the specific mechanisms of action."

Fitsch emphasizes that when using imaging methods, a large number of decisions have to be made in advance - for example, regarding the relevant brain areas or the statistical analysis of the data. The strongly visual fMRI imaging, which supposedly provides objective images of the working brain, seduces many laypeople, but also scientists, into underestimating the size of the actual scope for interpretation. The more interpretative a methodological approach, the more likely it is that implicit assumptions, for example about the expected differences in activity, creep into the research process.

In some cases, depending on the evaluation method used, the same data set "proves" sometimes differences and sometimes similarities between the sexes. The psychologist Anelis Kaiser and colleagues published an imaging study in which she examined the Broca area responsible for speech production in 44 test subjects. In contrast to previous studies, the language centers in both hemispheres of the male participants were equally activated, whereas the Broca area of ​​the left hemisphere dominated in the women - or so it seemed. But when the researchers simply changed their evaluation method and applied stricter statistical standards, the difference suddenly disappeared! A stronger activation of the left Broca center compared to that in the right hemisphere was recorded in both sexes.

What sounds like a mathematical gimmick can have tangible consequences. This is because statistically significant differences between test subject groups are more likely to be published in scientific journals than so-called zero results - i.e. studies in which no effects could be found. This so-called publication bias has long been a known problem.