Intelligence is wildly complicated. There are a variety of different types, from spatial to mathematical to musical ability, and raw talent interacts with our habits of mind and the situation to make us functionally smarter or dumber at different times.

For all these reasons, you'd imagine that spotting physical signs of intelligence in the brain would be incredibly tricky, but according to Big Think, apparently a team at Yale has already managed such a feat.

Who needs an IQ test when you have an MRI machine?

For a recent study, the neuroscientists scanned the brains of 126 subjects with a fMRI machine and, just buy looking at the results, were able to predict their scores on a test that measures a kind of intelligence known as "fluid intelligence," which involves the ability to recognize patterns, solve problems, and identify relationships, and which has been established as a decent predictor of academic performance.

Brains with more connections between two regions known as the frontal and parietal lobes, it turns out, display more fluid intelligence, and the number and strength of these connections is visible from an fMRI scans.

Big Think points out the point of the study wasn't to develop a new technique to assess intelligence. Instead the work was done as part of the Human Connectome Project. which aims to map the connections in the human brain. It turns out that the specific ways our various brain regions are wired together is not only a good indicator of our level of smarts, but also as unique as a fingerprint.

The scientists "could identify one participant from another with 99% accuracy, from their brain scan," Big Think reports.

Curative, but also creepy

That level of detail may eventually help scientists develop personalized treatments for tricky brain diseases like schizophrenia. But in the meantime, being able to objectively measure someone's intelligence with such a test is also a little creepy.

While tailoring treatment or educational interventions based on brain data sounds great, other less appealing uses of the technology can easily be imagined. "It's a double-edged sword," neuroethicist Laura Cabrera told Wired in relation to the same research. Cabrera goes on to note that brain scans could be used to decide who gets into college, covered by insurance companies, or even hired.

But we still have lots of time to discuss the ethical implications of this technology and design rules to ensure it serves the common good. "It's not wrong to say there are weird ethical implications to this," study co-author Emily Finn commented in the same article, "but we're still a long way from doing this with enough accuracy to apply in the real world."