Evolutionary Psychology
Evolutionary psychology (or EP) examines psychological traits like memory, language, and perception, from an evolutionary perspective, which is modern. This theory seeks to identify the human psychological traits that are evolved adaptations. These are the traits, which are the functional products of sexual selection or natural selection. According to the adaptationists, physiological mechanisms are related to psychological processes. They consider the physiological mechanisms of the heart, immune system, and lungs.
Some of the evolutionary psychologists apply this thinking to psychology, and argue that the human mind has a similar modular structure to the human body, where different modular adaptations serve different functions. According to evolutionary psychologists, a lot of the behavior exhibited by humans is the product of psychological adaptations, which evolved to solve their recurrent problems in the environments of their ancestors. This field of evolutionary psychology is steadily becoming influential in the field of psychology. According to evolutionary psychologists, EP is not just a sub-discipline of the larger field of psychology. They argue that evolutionary theory is sufficient in providing a metatheoretical framework at the foundational level that integrates the whole psychology field, in a manner similar to that used for biology.
According to evolutionary psychologists, traits or behaviors that take place universally in every culture are very good candidates for the mentioned evolutionary adaptations. These include the abilities to deduce facts from others' emotions, to discern non-kin from kin, prefer and identify healthier mates, or to cooperate with other people. This makes it possible to predict issues such as intelligence, marriage patterns, bride price, infanticide, perception of beauty, promiscuity, and parental investment.
Premises
The theory of evolutionary psychology is based on several central premises. The first premise is that the brain is a device that processes information, and produces behavior to respond appropriately to internal and external inputs. The brain has adaptive mechanisms, which were shaped by sexual, and natural selection. This theory also argues that there were different neural mechanisms, which were specialized for problem solving in the evolutionary past of humanity. With time, the brain evolved some specialized neural mechanisms, which were designed for problem solving, especially for the problems that recurred as evolution continued and time went by, giving modern human beings stone-age minds.
A vast majority of the processes and contents of the mind are unconscious. Most of the mental problems that appear easy to solve, happen to be extremely difficult, and these are solved unconsciously through complicated neural mechanisms. The theory also argues that human psychology is made up of a large number of specialized mechanisms, with each of them being sensitive to unlike classes of inputs or information. These mechanisms combine and produce manifest behavior.
The findings and theories of Evolutionary Psychology have applications in a large number of fields, including economics, management, psychiatry, politics literature, environment, health, and law.
Controversies Concerning Evolutionary Psychology
Some of the critics of this perspective have raised questions on the testability of the theories. Others are on the assumptions made in evolutionary and cognitive assumptions (such as the modular functioning in which the brain operates, and large uncertainty on the ancestral environment). Some critics are also concerned with the importance of non-adaptive and non-genetic explanations, and the ethical and political issues that could arise due to interpretation of the research results.
Behavioral genetics
Behavioral genetics examines the role played by genetics in animal and human behavior. It is usually associated with the debate on "nature versus nurture". Behavioral genetics is interdisciplinary, and it involves contributions from biology, epigenetics, ethology, psychology, genetics, and statistics. Most behavioral geneticists study how behavioral traits are inherited. In humans, the information is usually gathered by using the twin studies or adoption studies. In animal studies, transgenesis, gene knockout and various breeding techniques are common. This field is very closely related to Psychiatric genetics.
The relationship between genetics, or heredity and behavior, dates back to the work of Sir Francis Galton, an English scientist who lived between1822–1911. He coined the saying “nature and nurture.” He studied the families and relatives of outstanding men, who lived in his days and finally concluded, like Charles Darwin his cousin that mental powers normally run in families. He became the first person to use twins for genetic research and started many statistical analysis methods used today. In 1918, the British geneticist Ronald Aylmer Fisher wrote a paper to show how the laws of Gregor Mendel’s on inheritance, could be applied to complex the traits influenced by environmental factors and multiple genes.
The very first research on human behavioral genetic influence on mental illness and intelligence began in 1920, when environmentalism (that is, the theory that human behavior resulted from non-genetic factors like various childhood experiences) was popular. This was before Nazi Germany abused genetics and made the notion that hereditary could influence behavior abhorrent. Even though genetic research continued to be carried out on human behavior throughout the decades that followed, it was not until the 70s that a more balanced view prevailed in psychiatry and recognized the significance of both nature and nurture. However, in the field of psychology, this reconciliation never took hold until the 80s. a lot of the behavioral genetic research carried out today focuses on the identification of specific genes that could affect behavioral dimensions like intelligence and personality, and disorders, such as hyperactivity, depression, schizophrenia and autism.
Methods
The main goal of the field of behavioral genetics is usually to establish the causal relationships between behavior and genes. One of the more common approaches in this field is the reductionism. Here, scientists first examine a behavioral or psychological function (for example, schizophrenia). They then use the known functions of neurotransmitter systems and brain systems, to correlate behavior to the specific brain areas (for example, excess release of glutamate may stimulate excess production of dopamine within the limbic system, and this would lead to schizophrenic symptoms). After the scientists are able to connect behavior to various biological systems, they are then able to turn to genetics in order to understand how these biological systems developed (for example, abnormal glutamate genes could be the cause of schizophrenia). The first attempts to associate a particular genes (or chromosomal position) to behavior usually involve searching for QTL, or (Quantitative trait loci). With human populations, other methods used involve adoption studies and twin studies. These two methods try to separate environmental and genetic contributions to behavior.
The Human Genome Project made it possible for scientists to comprehend the coding sequence found in human DNA nucleotides. After candidate genes for various behaviors are discovered, i8t becomes possible for scientists to genetically screen different individuals in order to determine their chances of developing some form of pathology.
With animals (non-humans), selection experiments are often employed. For instance, breeding laboratory house mice for the observation of open-field behavior, voluntary hamster wheel-running behavior, and thermoregulatory nesting.
Behavioral Neuroscience
Behavioral neuroscience is a perspective that applies the principles of neurobiology, to studying physiological, developmental, and genetic mechanisms of behavior. Scientists do this by using both non-human and human animals. It investigates different things at the level of neurotransmitters, nerves, brain circuitry and other basic biological processes underlying abnormal and normal behavior. In most cases, experiments carried out in behavioral neuroscience usually involve animal models which are non-human (such as rats, mice, and primates which are non-human) which have implications that could lead to a better comprehension of human pathology, thereby contributing to practice which is based on evidence.
The distinguishing characteristic found in behavioral neuroscience experiments is that either one of the variables, the dependent variable used in the experiment is biological, or the independent variable is biological. What this means is that, the nervous system belonging to the organism being studied is temporarily or permanently altered, or some other aspect of this nervous system may be measured (it is usually related to a given behavioral variable).
Generally, behavioral neuroscientists study themes and issues, which are similar to academic psychologists, although they are limited by their need to use animals, which are nonhuman. As a result, most of the literature found in behavioral neuroscience covers behaviors and mental processes that are shared by different animal models. For instance, sensation and perception control of movement, motivated behavior (such as hunger, thirst, and sex), learning and memory, emotion, and sleep and biological rhythms.
However, with increases in technical sophistication and the development of more accurate noninvasive methods, which can also be applied to the human subjects as well, behavioral neuroscientists are now beginning to contribute knowledge to other areas of psychology, linguistics, and philosophy, such as language, consciousness, and reasoning and decision making. This science has also made contributions a better comprehension of medical disorders, as well as the ones that fall under the purview of biological psychopathology and clinical psychology (that is, the ones in abnormal psychology). Although there are no animal models for all the mental illnesses, this field has contributed a lot of important therapeutic data covering a wide variety of conditions, which include: Parkinson’s disease, Huntington's disease, Alzheimer's disease, clinical depression, schizophrenia, autism, anxiety, drug abuse, and alcoholism.
Limitations and Advantages
Behavioral neuroscience involves different manipulations, and they have limitations and advantages. For instance, neural tissue, which is destroyed by electric shock, neurotoxicin or surgery, is a permanent type of manipulation and consequently limits any follow-up investigation. This is true for most techniques of genetic manipulation.
One of the advantages of behavioral neuroscience is that temporary lesions are achievable with advances in genetic manipulation, for instance, certain genes can be switched on or off with proper diet. Pharmacological manipulations allow scientists to block certain neurotransmitters temporarily to enable the function to return to its original state after the metabolism of the drug.
Conclusion
Of the three perspectives, the most valid is behavioral neuroscience. This is because it uses scientific methods that can be measured, and the data collected is easy to analyze. It is reliable, and its methods can be replicated for other studies. It has also contributed more to the sciences than the other perspectives, making it more useful.
References
Freberg, L. (2010). Discovering Biological Psychology. New York: Cengage Learning.
Kalat, J. W. (2009). Biological Psychology. New York: Cengage Learning.
Kassin, S. (2004). Psychology. New York: Prentice Hall.
