Behavior is anything an organism does—any action we can observe and record (Myers, 2011, p. 4). However, this is just a simple explanation limited by our outside view of a person's reaction. Inside the body there is so much more happening that can help explain the direct correlation between the cause (stimulus) and the effect (reaction). Everything psychological—every idea, every mood, every urge—is simultaneously biological (Myers, 2011, p. 35). That is because there is a direct link between biology and behavior. The body communicates sensory and motor stimuli through the nervous system, an integral part of human behavior. The two part nervous system works together to send messages and translate them into reactions. The peripheral nervous system (PNS) acts as the road from sensation to reaction by delivering sensory feelings to the central nervous system (CNS) via the nerves. The CNS, specifically the brain, translates the sensation into a command for action. Motor neurons of the PNS then travel back along the nerve pathway to influence the organism's muscles or glands demanding a fitting reaction. This chemical process is constantly occurring in each individual.
As well as controlling our physical reactions, the brain serves as the center for all mental activity from emotions and sensitivity to critical thinking and speech. Different areas of the brain control different functions, for example the cerebrum, which handles such complex mental activities that it merits a four lobe division; each operating to control either visual or auditory or sensory or motor duties. If there was damage to any one of these lobes the person would be affected. Say the prefrontal lobe which is thought to be some sort of“executive control system”because it monitors, organizes, and directs (Weiten, 2007 as cited in Kane & Engel, 2002; Shimamura, 1995) was damaged. It would cause deficits in planning, organizing and paying attention (Weiten, 2007 as cited in Fuster, 1996).
Another important part of the brain and a member of the endocrine system is the hypothalamus, which plays a major role in the regulation of basic biological drives related to survival, including the so-called“four f's”: fighting, fleeing, feeding and mating (Weiten, 2007 p. 90). Known as the master gland, the hypothalamus works in conjunction with other glands belonging to the endocrine system. For example, the hypothalamus might secrete a GnRh (gonadotropin releasing hormone) stimulating the anterior pituitary gland to release the hormone LH (luteinizing hormone) which will then travel through the blood stream until it reaches its target, in this case the ovaries, and cause the synthesis of hormones estrogen and progesterone, which in turn are essential in the development of a normal female (Anestis, 2012).
So when a psychologist is observing behavior, he is seeing the outward effect of what is going on inside. Picture the following scenario: a person shouted angrily at an individual for asking him a question. The cause is the question and the effect is the angry shouting. But, pull this reaction apart biologically. The question enters as a sound via the auditory canal and is carried by the nerves to the brain, primarily the cerebral cortex where the sound is...