>How and why is it that we start life so similar to one another, and yet grow into such different adults?
>Babies are very similar to one another, yet as we grow we change into very different people. Why? If we change so much before having children then why aren’t our children more different to those of the neighbour (and don’t say maybe they’re the neighbour’s children)?
Battison's Blog 
>This is largely a guess (I'd like to learn more about the topic, and thought we didn't have enough psychology questions, hence why I started it). But what does everyone think to it being an evolutionary feature? Babies are born with almost all the neurons they will ever have, more than 100 billion of them. Yet at birth our brains develop certain sections (known as the autonomic functions, including the brainstem and mid-brain) first, which are deemed necessary for survival. Evolution occurs more slowly the more complex is the life form. Hence I would contend that any changes started through epigenetics (the adaptation of genes throughout a person's life) in the parent's lives have very minor consequences for the development of the autonomic functions. This means that the genetic variations between and within generations in the first year of life vary little.However later experience (i.e. nurture rather than nature) selects which other parts are developed most. Indeed the last regions of the brain to fully develop are the limbic system, involved in regulating emotions, and the cortex, involved in abstract thought. The growth in each region of the brain largely depends on receiving stimulation, which spurs activity in that region. This stimulation provides the foundation for learning. Hence developments that occur after the autonomic functions are developed are more subject to nurture and the environment.