A team of scientists believes they have developed a new way to determine how closely related modern humans are to various ancestors: the size of their wisdom teeth.

Published in the journal Nature, the new study attempted to tie wisdom teeth size to the use of certain tools. They suggest the teeth became smaller as man evolved, but they also focused on teeth because the hard enamel makes them the fossil that most commonly survives.

"Teeth can tell us a lot about the lives of our ancestors, and how they evolved over the last seven million years. What makes modern humans different from our fossil relatives? Palaeontologists have worked for decades to interpret these fossils, and looked for new ways to extract more information from teeth," study lead author Dr. Alistair Evans, an evolutionary biologist at Monash University, said in a press release. "Our new study shows that the pattern is a lot simpler than we first thought - human evolution was much more limited."

The researchers found a connection between the size of humans' wisdom teeth size and the introduction of advanced tools. As people were designing better and better tools, they needed their teeth less and less.

"It's always been presumed that sometime in early Homo, we started using more advanced tools," Evans told Live Science. "Tool use meant we didn't need as big teeth and jaws as earlier hominins. This may then have increased evolutionary pressure to spend less energy developing teeth, making our teeth smaller."