The Science & Evolution of Self Sacrifice

All creatures in nature want to preserve their life, live long enough to pass on their genetics and ensure their survival .... except humans. Some humans will gladly give their lives to protect and save they ones they love and even complete strangers. But with a trait like this questions arise. How did self sacrifice evolve? Are certain people more willing to sacrifice themselves than others? How has self sacrifice genetics withstand the test of time? Join Nick and Mike as they discuss the science of self sacrifice from chemicals in the brain to how nature and nurture effect people's willingness to lay their life on the line.