Some problems humans deal with has to do with brain chemistry, and they seem to just be wired differently than the average person. Maybe, truth is, all of us are wired differently than others. There are some truly chaotic people are capable of. Deviant people are sometimes those kind of people. An example of deviance has gotta be someone who is capable of killing another human being.
Murder is probably the most deviant things a human being can do, if deviance was quantifiable. There are particularly two different kinds of murder. Impulsive, and premeditated. According to Erin Spain of Northwestern University, Impulsive murderers usually are more mentally unstable, possibly due to rage, while premeditated murders differ psychologically and intellectually. But both types of people usually will have some intent behind their actions.
There are some different theories that could explain what is causing someone to kill another person.
Rational Choice Theory – An impulsive murderer may become filled with anger towards another person and burst and kill them without thinking everything through. A rational choice may not have been made, but an irrational choice may have. But a premeditated murderer definitely is weighing the costs and benefits to committing this act. Premeditated means they have had the opportune time to consider their actions, and feel they should still go through with it.