According to thompson, meyers, and jochem, caregivers' attempts to infants soothe their emotions influence:

I believe the answer is Neurobiological regulation of emotions
The existence of caregivers tend to make the infants feel safe/secure due to the protective feeling that they may felt.
This lead to their bodies able to slow down their heart rate and create a more happy, relax, or calm emotions

Ithink it’s bill gates.