FWIW — and not to criticize you, I’m a parent and know what you’re going through — evolution didn’t do this to us, we did. If we look at our closest relatives, the other primates, infants all sleep snuggled with their mothers. As they get older, they snuggle together or with other relatives. It’s very rare for any of them to sleep alone.

Imagine a baby chimp or gorilla waking up alone in the forest after having fallen asleep snuggled with its mother. Of course it would be terrified, of course it would cry for help.

Many modern cultures choose to make infants sleep alone. That doesn’t do away with the infant’s hard-wired responses, long-set in its genome.