| Babies sleep better when their head is near their mother's heart. This seems to be the obvious reason for the left-handed cradling bias [1]. If a baby sleeps better, it cries less. If it cries less, it attracts fewer predators and helps both parents sleep better at night and have more energy. It also allows the mother to do things with her dominant hand if she is right-handed. Given the left-handed cradling bias exists even with left-handers, it means there is something specific with left-handedness and infant rearing. A baby in the left hand and a tool (or weapon) in the right is biologically efficient. Most studies take this from the perspective of evolutionary advantage of the individual. They should take it from the perspective of evolutionary advantage of the family, without which the baby does not survive. If the bias confers evolutionary advantages, that is also important for the longer childhood humans have compared to primates, which supports our larger brains. Any differential here would have a feedback effect. Wouldn't it be interesting if a key reason humans are the way we are is a mother's love ♥? [1] https://sites.psu.edu/clarep/2024/04/12/the-left-cradling-bi... |