Picture this example of mirroring bad behavior. A child is misbehaving and throwing their toy blocks around. The parent hits the child back with the block and doesn’t teach problem-solving.
Martin Teicher at Harvard University and others have been studying the effects of child abuse on brain development. They have discovered that all types of abuse (physical, sexual, emotional, verbal and neglect) can cause hormones to saturate the brain in a way that actually damages the corpus callosum and makes it smaller after enough repeated abuse.
How does this happen? Apparently, when a person is stressed, cortisol – also known as the stress hormone – is released. At first, this can be a good thing. Cortisol sharpens the brain’s problem-solving abilities and memory, while also triggering an increase in energy for the muscles to prepare for intense fight or flight. This is supposed to help us quickly deal with the problem.
However, if our brains and bodies are awash with cortisol for longer than about thirty minutes (constant, repeated stress), then it interferes with our brain cells replenishing themselves and with enough continued exposure to cortisol they can actually shrink or even die. So if the child’s mom or dad hits her with the block or yells repeatedly or engages in other abusive behavior a lot, Caitlin won’t grow useful connections between upsets and problem-solving.
But even worse, if she repeatedly is stressed enough, it may trigger too much cortisol for too long on her brain, and may shrink or even kill some of her brain cells. The long-term effects of this can lead to an adult personality disorder, with an inability to manage her own emotions and an inability to solve problems consistently.