This chapter goes into what has an influence on children in terms of development later on in life. All of these studies and subsequent theories are grouped into a type of psychology called developmental psychology. A big component on developmental psychology is looking into the effects of experiences during early childhood. Early experience during childhood can have a profound impact on brain development and influence one's entire life. However, this does not mean that children are fragile in their early lives and are easily damaged by the negative effects of early deprivation.
I found it quite interesting that the human brain begins to develop only eighteen days after fertilization all the way into early adulthood. While most of the body's other organ are fully developed by birth, the brain takes much longer to fully develop and is not completely developed at birth. At infancy, babies have a set of motor behaviors that are sparked by stimulation and are important to survival. One of these needs is the sucking reflex, which is that a baby will clamp down and suck on anything put in its mouth.
Chapter 10 strongly asserts that there are many different connections that an infant has to its surroundings that are stimulated through connections with their parents as well as through interactions with their environments. I hope that this chapter can explain how much someone's personality is determined by their surroundings as opposed to their genetics.