As a measure of what sets humans apart from other primates, cumulative knowledge seems as good as any. However, the result of this study that interests me the most has nothing to do with monkeys. It’s that the scientists saw “evidence for cumulative culture in five of eight groups” of toddlers.

That means that 37.5% of their test subjects did NOT show evidence for cumulative learning. What about them?

Were they the youngest groups? Were they groups of strangers? Did kids in those groups have autism spectrum disorders? Or is 37.5% of humanity not capable of learning from each other?