I think it can't, but I can't explain why. could have heard can replace would have been able to hear, right? Thank you, in advance.
A sleeping mother has the ability to identify the particular cry of her own baby. This is one of the bonding factors that has been forgotten because of the way in which we live today. Typically, there is now only one newborn baby in any family house or apartment, so there is no way to test this ability. In an ancient tribe, however, living in small huts in a tiny village settlement, a mother would have been able to hear any of the babies crying in the night. If she woke up every time one of them screamed for food, she might get no sleep at all. During the course of evolution she became programmed to awake only at the sound of her own particular baby. This sensitivity is still there to this day, even though it is seldom used.