Voluntary behavior refers to thoughts and actions aimed at or resulting from choice in nature by individuals. The opposite behavior is called reflexive or involuntary behavior. As of 2014, the existence and nature of voluntary behavior is a matter of some debate amongst neuroscientists, psychiatrists and psychologists.
The existence, mechanics, causes and results of voluntary behavior have been areas of intense curiosity and study since psychology came into existence. The concept of voluntary behavior is closely bound to science's understanding of the consciousness, or self. Psychiatric and neurological evidence suggest that two systems of reasoning exist: the rule-based system, which deliberates and makes conscious decisions, and the associative system, which is unconscious and hidden, reacting impulsively to stimuli. Understanding voluntary behavior may lead to a better grasp of why humans, as individuals and groups, make the decisions they do and whether or not free will plays a part.