The Human Brain Rigidity and Plasticity Dualism – The Reptilian and Limbic Brains are quantum-chemically-electronically wired to be negativistic when threatened and in accepting new information. Reptilian and Limbic Brains have significant instinctual deterministic ways of interacting with the world. The Reptilian Brain is positioned to rigidly defend from outside threat. The Limbic Brain is set up to stubbornly engage environmental stimuli. Early developmental learning (ages 0-7) takes place at the Limbic Brain emotional level. The early Limbic Brain learning of one’s cultural norms, beliefs, fears, worldviews are implanted for a lifetime. The very sense of oneself, positive or negative, is engrained at this early age. The acceptance of our natural impulses are set at this Mammalian Brain level. Skills of learning, adapting, and changing can be traced back to the formative years of ages 0-7. Much of the rigidity that comes from the Limbic emotional brain spills over into the Neocortex thinking brain. However, and importantly, the Neocortex has a cognitive capacity that is open to learning new information. Posts to come will detail the rigid parts of our brain, and the more flexible and adaptable parts.