Behavior
A lot of people attribute behavior with a mind, a soul, or a set of morals. For example, the saying "mind over matter" suggests that a mind controls how someone behaves and responds to a certain situation. If you think about it, though, where is the mind located? In the head? The heart? What is really dictating this behavior? According to science, there is no structure for a mind or a soul, leaving only the brain to control behaviors.
Chemicals Change Behaviors
Physical structures or changes in the brain dictate behavior. One way this happens is in the release of chemicals that result in certain feelings and therefore actions. For example, when the brain releases serotonin, the feeling that accompanies is labeled as "happiness." As a result, you may smile, causing your eyes to squint, your cheeks to lift, and the sides of your mouth to wrinkle. On the other hand, lower levels of dopamine in the brain is labeled as depression, causing behaviors such as frowning, poor posture, and negative thoughts.
Structures Change Behaviors
Physical structures or changes in the brain dictate behavior. One way this happens is in the parts of the brain that control how your body responds to signals. For example, in a properly functioning body, the brain stem is an intermediate structure between the brain and the spinal cord that relays messages from muscles to brain and brain to muscles. However, for people whose brainstems are severed, this carrying of messages cannot occur. As a result, symptoms include a lack of ability to maintain a heartbeat, the need of a machine to carry out respiration, and eventually death as the body can no longer carry signals and perform basic functions. This is a very extreme example of a malfunction in a structure leading to a detrimental behavior.
Another famous example of brain structures altering behavior is that of Phineas Gage. Gage worked building railroads by blasting apart masses of rock with dynomite. When the dynomite exploded early, the pole he used to push it into the hole shot up and through his head, destroying most of his frontal cortex. Gage survived, but his behavior was affected because of the loss of function of the frontal cortex. Since that region of the brain determines concentration, the ability to plan, and the ability to conceptualize societal norms and social cues, Gage lost this, causing him to behave like a child with a short attention span, a major focus on the present without looking ahead, and impulsively unable to follow societal norms.
