In the psychological study of human behavior, heredity and hormones are often contrasted to each other. Undoubtedly, hormones and genes (heredity) invariably impact human behavior. Scientists may claim the prevalence genes’ or hormones’ impact on human behavioral patterns, but “fast-growing understanding of the human behavior has recently made it clear that both sides are partly right” (Ketterson, 2005).
This is why it is critical to re-consider the physiological and genetic foundations of human behavior through the prism of hormones vs.genes behavioral debate. Science has not yet been able to answer the basic question how genes impact human behavior. Pfaff (1997) recognizes that “we still cannot easily trace the causal routes and mechanisms by which genes could influence behavior”. However, the current state of scientific knowledge suggests that human behavior is determined by a variety of genes, and a variety of hormones. Human behavior is never determined by one particular gene, but is the consequence of the complex interaction between the human heredity and the brain.
Similarly, there is no single hormone which would relate to a particular human behavior. The key element of genetic impact on human behavior is epigenesis – “a construction process within an organism that supplements the information provided by the genetic make up of that organism” (Carter, 1997). As a result, we have a psychological picture of human behavior which is shaped by the influence of multiple genes, and equally, multiple hormones. Human sexuality makes it possible to see the similarities and differences in the way hormones and heredity impact human behavior.
The development of human sexual orientation, the impact of sexual hormones on personal identity, and the genetic influence of the sexual behavior make the correlation between hormones, genes, and behavior more understandable. “Brain is a sexually differentiated organ, that is, fetal and perinatal sex hormones have organizational effects on brain structure and also have subsequent activational effects on the brain” (Ketterson, 2005). In this manner, hormones determine human sexuality, regulate human sexual behavior, and impact the structure of human cognition.
For example, the changes in the estrogen levels in female organism determine the effectiveness with which women deal with male-favoring or female-favoring tasks: “during high estrogen levels female-favoring tasks such as fluency and fine motor skills were positively affected” (Carter, 1997). As we see, the level and concentration of hormones in human organism changes under the impact of various external and internal factors. Genetic structure of a human organism is similarly unstable. Humans have some 30,000 genes (Pfaff, 1997).
Although the two different people may display up to 10,000 genetic differences, the major portion of genes is transmitted from parents to children. Genes work to produce numerous biochemical compounds which ultimately determine the way we behave in specific social environment. It should be noted, that genes similarly determine the structure and predominance of human hormones. This is why the correlation between genes, hormones, and human behavior becomes even more complex. As mentioned earlier, hormones and genes are equally impacted by environment: “even at the cellular level, environment affects the activity of genes.
Most active genetic material does not code for any kind of trait. Instead it regulates the speed and direction of the expression of other genes; i. e. , modulates the unfolding of the genome” (Carter, 1997). However, as environment impacts the release of hormones from the outside, genes usually act from the inside of the human organism, producing enzymes, synthesizing hormones and stimulating (or repressing) certain behaviors. Ketterson (2005) states that behavior can exist without hormones; but behavior cannot exist without genes.
Thus, the role of a gene (heredity) is to produce certain behavioral pattern. This pattern is further repressed or facilitated with the help of hormones. Genes determine the basis of the human behavioral structure, while hormones further change the motivational system of human psychology. Moreover, hormones are frequently referred to as neurotransmitters in the development of human behavior: they are “used in communication between neurons in the brain just like other chemicals” and are produced as the human organism reacts to changes in external social environment (Pfaff, 1997).
Peptides are the most recent scientific examples of the way hormones impact human behavior. Peptides determine the activity of the central nervous system, and are integrally linked to the expression of maternity and satiety in women. Simultaneously, maternity is also determined by the genetic structure of female organism, and peptides’ role is limited to facilitating the development of this psychological ability in humans (Carter, 1997). Conclusion Genes and hormones shape human behavior.
Genes and hormones form a complex combination of psychological factors which determine the direction of behavioral development, and facilitate the display and expression of particular behavioral patterns. Although genes and hormones are equally subject to changes under the impact of external social environment, hormones represent the second stage in the production and development of human development. Genes form the basis of human behavior, and regulate the amount and composition of biochemical compounds in human organism.Genes also produce hormones, which either suppress or foster the development of particular behaviors.
References
Carter, S. (1997). Hormonal influences on human behavior. In S. Carter (ed), New Aspects of Human Ethology, pp. 141-162. Ketterson, E. D. (2005). Behavior: hormones in the middle. Science, 310 (5756), pp. 1905- 1906. Pfaff, D. W. (1997). Hormones, genes, and behavior. Proceedings of the National Academy of Sciences of the United States of America, 94 (26), pp. 14213-14216.