Why is it that babies recognize their mothers at 40 days, and two-month-old babies don't recognize their mothers but only their grandmothers?

From the day a baby is born, probably many mothers will fantasize about when they can call their mothers, when they can recognize their mothers and so on, in fact, some babies recognize their mothers at 40 days, so why is it said that babies recognize their mothers at 40 days, and two-month-olds do not recognize their mothers but only their grandmothers?

Some babies can recognize their mothers at 40 days, but it doesn't mean that they can recognize their mothers' appearance. They recognize their mothers by the smell of their mothers, the sound of their mothers' heartbeats, and the taste of their mothers, and vision is only the first step in their recognition of their mothers.

Many people find that two-month-old babies don't recognize their mothers, but only their grandmothers. The reason for this is that the babies are not breastfed, but are raised on formula, and the grandmothers usually feed the babies, so there is no breastfeeding connection in the day-to-day life, and the babies see their grandmothers more often, so the babies only know their grandmothers and don't recognize their mothers.

The baby does not know the mother only knows the grandmother after this situation, we do not have to worry about, the mother usually more interaction with the baby can be, you can usually more contact with the baby, you can touch the baby. And the baby to make eye contact, this time the baby will be in a deeper impression, in the baby two months, the mother can also give the baby read aloud to the baby to remember the mother's voice.