“Let the baby cry it out.”
– some parent somewhere probably

The idea of “cry it out” is that if you picked up a baby every time it cried, it would create a dependency on the parents and grow up to be clingy and have attachment problems as an adult.

But in fact, letting a baby cry it out, i.e. leaving it alone and not picking it up, is what actually causes insecure attachment, leading to the adult behaviors of fear of abandonment and separation anxiety.

The second form of attachment is called avoidant attachment, which is also caused by not picking up babies when they cry. This is shown in children who seem detached and uninterested in their caregiver.

Picking up a baby when it cries actually promotes secure (i.e. healthy) attachment, leading them as adults to choose secure partners and understand how to have a healthy relationship.

You cannot spoil a child by loving it too much.