Gizmodo talks to a researcher who thinks so:
What were these tools used for?
Upright female hominins walking the savannah had a real problem: their babies couldn’t cling to them the way a chimp baby could cling to its mother. Carrying an infant would have been the highest drain on energy for a hominin female – higher than lactation. So what did they do? I believe they figured out how to carry their newborns using a loop of animal tissue. Evidence of the slings hasn’t survived, but in the same way that we infer lungs and organs from the bones of fossils that survive, it is from the stone tools that we can infer the bits that don’t last: things made from sinew, wood, leather and grasses.
How did the slings shape our evolution?
Once you have slings to carry babies, you have broken a glass ceiling – it doesn’t matter whether the infant is helpless for a day, a month or a year. You can have ever more helpless young and that, as far as I can see, is how encephalisation took place in the genus Homo. We used technology to turn ourselves into kangaroos. Our children are born more and more underdeveloped because they can continue to develop outside the womb – they become an extra-uterine fetus in the sling. This means their heads can continue to grow after birth, solving the smart biped paradox [that walking upright should favor smaller brains]. In that sense technology comes before the ascent to Homo. Our brain expansion only really took off half a million years after the first stone tools. And they continued to develop within an increasingly technological environment.