Rather, we are only slightly better, a fraction of a percent better. The compounding of that fraction of 1% over 4-7 million years has led to the dramatic differences between us and the rest.
That's why the article says it's a mystery. Humans are looking for a thing. Something we have they don't. There isn't anything. We just do those things better, faster, more dramatically and for longer which has widened the gap between what we have and what they have.
Same would be true of a human being who compounded their wealth over time. Families who have compounded their wealth for just a few decades now have as much wealth as half a planet of humans. We don't ask for what one thing separates them from us, we know what it is. The power of compounding interest over time.