The Biological Approach to Psychology PDF

## The Biological Approach to Psychology ### Assumptions - The biological approach believes behavior to be a consequence of our genetics and physiology. - It's the only approach in psychology that examines thoughts, feelings, and behaviors from a biological and physical point of view. - All that is...

## The Biological Approach to Psychology ### Assumptions - The biological approach believes behavior to be a consequence of our genetics and physiology. - It's the only approach in psychology that examines thoughts, feelings, and behaviors from a biological and physical point of view. - All that is psychological is first physiological. All thoughts, feelings, and behavior ultimately have a biological cause. - A biological perspective is relevant to the study of psychology in three ways: 1. **Comparative method**: different species of animal can be studied and compared. This can help in the search to understand human behavior. 2. **Physiology**: how the nervous system and hormones work, how the brain functions, how changes in structure and/or function can affect behavior. (Ex: How prescribed drugs to treat depression affect behavior through their interaction with the nervous system). 3. **Investigation of inheritance**: what an animal inherits from its parents, mechanisms of inheritance (genetics). (Ex: Whether high intelligence is inherited from one generation to the next). - The biological approach argues that some of our behaviors and characteristics are passed on genetically because they enhance our survival, such as attachment and memory. ### Issues and Debates - **Free will vs. determinism:** It is strongly determinist as it views behavior as caused entirely by biological factors over which individuals have no control. - **Nature vs. nurture:** - The biological approach is firmly on the nature side of the debate. - It does recognize that our brain is a plastic organ that changes with experience, so it does not entirely deny the influence of nurture. - **Cross-cultural research** is vital, comparing behaviors (e.g., gender, facial expressions) across different cultures. If the behavior is similar across cultures, it suggests that differences in behavior are biologically (nature) based. - If the behavior is different across cultures, it is likely to be affected by the environment (nurture). Cross-cultural research contributes to the nature-nurture debate in psychology. - **Holism vs. reductionism:** - The biological approach is reductionist as it aims to explain all behavior by the action of genetic or biochemical processes. - It neglects the influence of factors such as early childhood experiences, conditioning, or cognitive processes. - **Idiographic vs. nomothetic:** - The biological approach is nomothetic as it establishes laws and theories about the effects of physiological and biochemical processes that apply to all people. - The research methods used are scientific, using scans and biochemistry. - Animals are often used in this approach as it assumes humans are physiologically similar to animals. ### Investigation of Inheritance - Twin studies provide geneticists with a kind of natural experiment in which the behavioral likeness of identical twins (whose genetic relatedness is 1.0) can be compared with the resemblance of dizygotic twins (whose genetic relatedness is 0.5). - If heredity (i.e. genetics) affects a given trait or behavior, identical twins should show a greater similarity for that trait compared to fraternal (non-identical) twins. - **Types of twins**: - **Monozygotic**: Identical twins (share 100% genetic information). - **Dizygotic**: Non-identical twins (share 50% genetic information, similar to siblings). - Research using twin studies looks for the degree of concordance (or similarity) between identical and fraternal twins. - Twins are concordant for a trait if both or neither of the twins exhibits the trait. - Twins are disconcordant for a trait if one shows it and the other does not. - Identical twins have the same genetic makeup, and fraternal twins have just 50 percent of genes in common. - If concordance rates (which can range from 0 to 100) are significantly higher for identical twins than for fraternal twins, then this is evidence that genetics play an important role in the expression of that particular behavior. - **Bouchard and McGue (1981):** Conducted a review of 111 worldwide studies comparing the IQ of family members. The correlation figures represent the average degree of similarity between the two people: - Identical twins raised together = .86 (correlation) - Identical twins raised apart = .72 - Non-identical twins reared together = .60 - Siblings reared together = .47 - Siblings reared apart = .24 - Cousins = .15 - Methodological flaws reduce the validity of twin studies, including poorly performed and biased studies. - Studies comparing the behavior of twins raised apart have been criticized, as the twins often share similar environments and are sometimes raised by a non-parental family member. ### Methods of Studying the Brain - The human brain is a highly complicated piece of biological machinery. Scientists have only just scratched the surface of understanding the many functions of the workings of the human brain. The brain can influence many types of behavior. - In addition to studying brain-damaged patients, we can find out about the working of the brain in three other ways: 1. **Neuro Surgery**: Brain surgery is usually only attempted as a last resort. (Ex: H.M., severe epileptic fits, hippocampus removed, resulted in severe anterograde amnesia - could not remember anything new). Significant for learning about role of hippocampus in memory. 2. **Electroencephalography (EEGs)**: This is a way of recording the electrical activity of the brain (non-invasive). Brain waves can be traced. Used to study sleep and its stages, including REM. 3. **Brain scans**: More recently, methods of studying the brain have been developed using various types of scanning equipment hooked up to powerful computers. - **CAT scan (Computerized Axial Tomography):** A moving X-ray beam which takes pictures from different angles around the head, building up a 3-dimensional image of which areas of the brain are damaged. - **PET scan (Positron Emission Tomography):** Uses a radioactive marker, providing ongoing pictures of the brain as it engages in mental activity. Wernicke-Gerschwind model (language). ### Timeline - **The Voyage of the Beagle (1805-1836):** Darwin formulated his theory of natural selection by observing animals while traveling the world. - **Harlow (1848):** Phineas Gage brain injury case study provides neuroscience with significant information regarding the working of the brain. - **Darwin (1859):** Publishes "On the Origin of Species by Means of Natural Selection". 1,250 copies were printed, most of which were sold on the first day. - **Jane Goodall (1957):** Began her study of primates in Africa, discovering that chimps have behaviors similar to those of all the human cultures on the planet. ### Evolutionary Psychology - **Edward Wilson (1975):** Published his book, **Sociobiology**, which brought together an evolutionary perspective to psychology. - **The birth of Evolutionary Psychology:** Begins with the publication of an essay, "The Psychological Foundations of Culture", by Tooby and Cosmides (1992). - **Charles Darwin proposed the theory of natural selection:** Argued that genetically determined characteristics or behaviors that enhance our chances of survival and reproduction would be passed on to the next generation and become more common in a population. Traits that do not enhance survival will gradually disappear. - **Theories within the biological approach support nature over nurture:** An example of behavior of evolutionary explanation is Bowlby's theory of attachment. - **Describing behavior solely in terms of either nature or nurture is limiting:** It underestimates the complexity of human behavior. It's more likely that behavior is due to an interaction between nature (biology) and nurture (environment). - **For example, individuals may be predisposed** to certain behaviors, but these behaviors may not be displayed unless they are triggered by factors in the environment. This is known as the diathesis-stress model of human behavior. ### Criticism - **A strength of the biological approach:** Provides clear predictions (e.g. about the effects of neurotransmitters or behaviors of genetically related people). These explanations can be scientifically tested, replicated, and peer-reviewed. - **A limitation of the most biological explanations:** Reductionist. They reduce behavior to the outcome of genes and other biological processes, neglecting the effects of childhood and our social and cultural environment. They don't provide enough information to explain human behavior fully. - **The biological abnormalities seen in mental disorders could be the result rather than the cause:** Brain is a plastic organ that changes with use, so damage could be the result of anxiety rather than its cause (Ex: Caudate nucleus). - **The unbalance in neurotransmitters (like low serotonin in depression)** could be the consequence rather than the cause of depression because the brain is a plastic organ that changes with the way we use it (depressed thinking causes low serotonin). - **Twin studies do not separate nature and nature because twins are raised and live in the same environment.** The difference in the concordance rate found between MZ and DZ twins could be due to the fact that MZ twins are treated more similarly by their parents because they look more similar. - **We usually do not find a 100% concordance rate in MZ twins for mental disorders:** Indicates that environmental and social factors must be involved in developing these disorders. - **The biological approach is determinist**: It sees our behavior as caused entirely by biological factors over which we have no control. This encourages people not to take responsibility for their actions and blame their genetic makeup.