Our brain’s biological path is not set, rather its development is a highly adaptive process that responds to environment and experience. Our earliest experiences and environments occur at the same time that our brains are going through their most rapid stages of growth, so those earliest experiences and environments are critical to how the development of neural circuits adapt to what kind of environment we, as biological organisms, are expecting (prenatal) or experiencing (postnatal).
Prenatal environments (the womb) respond to maternal emotional states and maternal emotional states are dependent upon the mother’s experiences and environments. So what the mother is experiencing while carrying a foetus in the womb, affects the foetus’s development and adapts it to expect the kind of environment that the mother is perceiving and that the foetus expects to be delivered in to, both in terms of physiology and neurology. For instance, high levels of the hormone testosterone during pregnancy, produced as a response to aggression, has been implicated in autism. So repeated or prolonged aggressive episodes during pregnancy appears to have developmental consequences.
Postnatal environments take in a lot of factors, but are predominantly determined by parental interactions during the first few years. The relationship with parental figures, especially the mother, and the level of safety and nurture experienced in that relationship, determine relational patterns throughout the rest of life. If our earliest emotional bonds do not cultivate a sense of safety in making an emotional connection to someone, subsequent emotional connections throughout life will be subject to feelings of not being safe as the fear memory system triggers the amygdala and HP Axis in to a stress response, initiating fight or flight behaviours in response to attempts at genuine intimacy with another.
Early stressful environments cause areas of the brain associated with the fear response to receive a boost in developmental energy. So these areas grow faster, bigger and more dominant than they would in a safe nurturing environment. At the same time, areas of the brain that would normally moderate the fear response don’t receive as much developmental energy as they would have in a safe and nurturing environment. This means that things that shouldn’t cause a big fear/stress response, in fact do cause a fear stress response that the situation doesn’t really call for. As this fear/stress response is autonomous, when it is triggered it becomes very dominant in our thinking, feeling and perceiving. So we may perceive certain things far more negatively than those things actually warrant. Whatever caused the initial stress will be stored away in our emotional memories which will be autonomously triggered by reminders of the initial emotional wound.