actions come in the form of both excitatory and inhibitory signals crossing the corpus callosum and other hemispheric bridges. As LHS and RHS each have unique interpretations of situations these signals allow for discussion and an ultimate decision to be made. This interaction is called hemispheric rivalry. This term is apt as both hemispheres are in conflict yet on the same team. In humans the reliance on both hemispheres is the basis of a number of functions including consciousness.
The LHS can be simplified to better understand its role in this rivalry. The LHS is centered around action and is often the driving force behind risky behaviors. This hemisphere heavily relies upon emotional input leading it to make brash and uncalculated decisions. These decisions should not be thought of as ill-conceived, rather illogical and raw.
Similarly the RHS can be brought into understanding by discussing a simple model of its role in the hemispheric interactions. The RHS can be thought of as the opposite of LHS as it relies primarily on critical thinking and calculations to reach its decisions. As such the conclusions reached by the RHS often result in avoidance of risk taking behaviors and overall inaction.
When viewed as action (LHS) and inaction (RHS) the anthropological development of these structures becomes elementary and logical. In environments of scarcity, like those faced by non-human animals, taking risks is the foundational approach to survival. In scarcity it is far more likely to die of starvation than to damaging stimuli from hostile animals or situations. However, in environments of abundance, as humans have observed, it is far more likely to die to damaging stimuli than of starvation. As such the anthropological development of first LHS then much later RHS is understandable.
This also brings clarity to differences observed in modern human brains between environments. In areas of prosperity, where warmth, food, and basic needs for survival are abundant RHS domination is prevalent. Unsurprisingly, in areas of scarcity where cold and limited food are concerns LHS domination is prevalent. This phenomenon has been recorded numerous times when examining LHS dominant cultures, such as those of the Arctic, to RHS dominant cultures, like Africa. Similarly, studies of animals such as the Chickadee have shown similar results. Yukon born chickadees have LHS dominance as compared to Texas born chickadees with RHS dominance. In exchanging Yukon borns for Texas borns it was shown that the action reliant Yukon birds consistently became the alpha of their new environment whereas inaction reliant Texan birds died shortly after their arrival in the Yukon. These studies explain the mass deaths incurred upon large migrations throughout history as people of prosperity attempted and largely failed to survive in scarcity.
When speaking of dominance it is important to recognize that each hemisphere continues to function semi-independently but their interactions become dominated by one side. That is, each hemisphere always provides its input to the decision making process but is drowned out by the other. This occurs as individual decisions are made that biologically alter the state of the brain, changing the weight each hemisphere carries in their rivalry. As a choice of activity or inactivity is made it influences how effectively one hemisphere can inhibit the other and simultaneously teaches the now less effective inhibiting hemisphere to provide more excitatory signals with more frequency. For example: if a child eats a cookie their LHS has successfully inhibited their RHS changing the power dynamic as to make LHS ever so slightly more dominant and RHS more submissive in their rivalry. The reverse is also true should the child not eat the cookie.
A lifetime of these anatomically changing decisions, paired with environmental circumstances as discussed above, dictate the structure and plasticity of the human brain. In cases such as common suburban living the LHS has less distinct neural networks and appears significantly blander than the 