Together heredity and hormones play an important part of behavioral psychology as scientists discover their individual roles. We inherit many of our physical traits such as eye color and height through genes passed down from our parents, many of these genes are being found to be related to diseases such as schizophrenia and Alzheimer’s. Research with lab animals is providing an insight into what genes can improve memory and learning abilities as well, pointing towards a conclusion that heredity might be more important in behavior than once thought.
Hormones play a large part in our behavior as well; together with heredity and environment, the three can form what defines us as individuals. The endocrine system is comprised of glands that release chemical hormones into our systems that can make us nervous, tired, happy or depressed; and even define us as male or female as with the hormones testosterone and estrogen respectively, an imbalance of which in either males or females might cause aggressiveness. Our gonads comprised of testes for male and ovaries for female are responsible for the secretion of these hormones.
Other glands of our endocrine system are likewise responsible for many other hormones that define who we are both psychologically and physically. Along with the gonads, the pituitary gland produces many other hormones that are related to our sexual drives as well as those that regulate body growth, blood pressure and other body functions. The thyroid and the four parathyroids contained within it release thyroxin and regulate our body’s levels of phosphates and calcium; the two together regulate our individual metabolism.
A small gland in the center of our brain known as the pineal gland produces the hormone melatonin which regulates when we are to be sleeping or awake. The pancreas releases insulin and glucagon to control our blood sugar level and the adrenal gland releases epinephrine and norepinephrine our heart rate when we become excited or come under stress and our body’s other physical reactions to such as eye pupil enlargement (Morris & Maisto, 2005, pp. 76-78).
Contained as part of deoxyribonucleic acid (DNA), our genes (approximately 30,000 in all) in unison define our weight, eye and skin pigmentation, height and other physical traits (Morris & Maisto, 2005, p. 80 par 1-3). One area of genetics is behavior genetics, here psychologists are interested in how our genes might affect our ability to learn and memorize tasks, our emotions and our personalities. Psychologists agree that our genes do not directly influence these behaviors; however do have an influence on our endocrine and nervous systems which in return can affect our behavior under certain conditions (Morris & Maisto, 2005, p. 0 par 6).
Selection studies on mice show that by breading them to contain specific genetic traits (much as with dogs) genetic profiles can be observed. When introduced into an environment with other mice that have not been specifically bred differences in temperament, intelligence as well as physical traits can be observed (Morris & Maisto, 2005, pp. 80-81). These differences can be described as hereditary traits passed through genes. Although it would be immoral and unethical to perform such studies on humans many of the same observances can be made.
By observing twins that were separated and raised in different environments, psychologists have discovered many similarities might still exist such as aggressiveness, depression and anxiety. If schizophrenia exists in one identical twin, there is a 50% chance the other will develop the disease and there is a 15% chance of the same for fraternal twins (Morris & Maisto, 2005, p. 82 par. 4).
These numbers are important because identical twins share an identical genetic makeup, where fraternal twins do not Darwinism and the theory of evolutionary psychology might also play a part in our behavior as well. Survival of the fittest” or at least the most adaptive has many believing that much of our behavior has been handed down over thousands of years. Traits such as our ability to learn language may prove many of our “natural” abilities. Personally, I believe all our complex abilities and problems are a mixture of genetic heredity, hormones, environmental conditioning and evolution interacting as a whole that makes us who we are as individuals.