A major effect of the short lifespan of hunter-gatherers was the crippling absence of grandparents:
Given that women would only start bearing by 17 or so, and die by their thirties, it would be common for parents leave their children in their tweens. We tend to think that a shorter lifespan is rotten — for the individual — and no doubt it is. But a short lifespan is extremely detrimental for a society as well. Because without grandparents, it becomes exceedingly difficult to transmit knowledge over time. Grandparents are the conduit of culture, and without them, culture stagnates.Imagine a society that not only lacked grandparents but also lacked language — as the pre-Sapiens did. How would learning be transmitted over generations? Your own parents would die before you were an adult and in any case, they could not communicate to you anything beyond what they could show you while you were immature. You would certainly not learn anything from anyone outside your immediate circle of peers. Innovation and cultural learning cease to flow.