Multi-Level Selection
Summary: After dozens of sections on human behavior, we have outlined the importance of evolution - via genes - on our modern behavior. Yet as simple and appealing as it may be to parse our behavior into “ genes ” alone, that is incomplete. Our behavior arises from a complex milieu of many influences acting simultaneously: our genetic programming, the results of that programming interacting with the genetic programming of those around us; and the changing environment in which our behavior plays out. Additionally, there are “ epigenetic ” effects: the expression or silencing of genetic functions which are toggled by environmental exposure and stressors during an organism ’ s lifetime. Genes are primary, but only one level of the story; evolution (and resultant behavior) happens at multiple levels of a system. Recently biologists began to refer to this new understanding as multi-level selection (MLS). 78 This acknowledges that one can ’ t make predictions about complex emergent behaviors based on a simple gene - based paradigm. Consider a non-human example. Scientists who were hired to expand egg production from chickens (since more eggs equals more money) did an experiment in which they selected the most productive egg-layer from a cage of nine chickens to parent the next generation. 79 If superior egg-laying ability could be passed on to one ’ s offspring, such selection should produce higher and higher egg production per cage over time.
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