Biological Approach In Psychology

On This Page:ToggleAssumptionsIssues and DebatesInvestigation of InheritanceMethods of Studying the BrainTimelineCritical Evaluation

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Biological psychology, also called physiological psychology, is the study of the biology of behavior; it focuses on the nervous system, hormones and genetics. Biological psychology examines therelationship between mind and body, neural mechanisms, and the influence of heredity on behavior.

Key Features• Natural Selection / Evolution• Adaptation• Scientific method• Heredity• Nomothetic (studies the group)

Methodology• Lab Experiments• Correlation studies• Twin research• Naturalistic observations• Cross-cultural research

Methodology• Lab Experiments• Correlation studies• Twin research• Naturalistic observations• Cross-cultural research• Electroencephalogram (EEG)• Brain scans (CT, MRI, PET)

Assumptions

The biological approach believes behavior to be a consequence of our genetics and physiology. It is the only approach in psychology that examines thoughts, feelings, and behaviors from a biological and, thus physical point of view.

Therefore, all that is psychological is first physiological. All thoughts, feelings & 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. For example, we could ask how prescribed drugs to treat depression affect behavior through their interaction with the nervous system.

Investigation ofinheritance: what an animal inherits from its parents, mechanisms of inheritance (genetics). For example, we might want to know whether high intelligence is inherited from one generation to the next.

Furthermore 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.

Each of these biological aspects, the comparative, the physiological (i.e., the brain), and the genetic, can help explain human behavior.

Issues and Debates

Free will vs. determinism

Nature vs. nurture

The biological approach is firmly on the nature side of the debate; however, it does recognize that ourbrain is a plastic organthat changes with experience in our social world, so it does not entirely deny the influence of nurture.

Cross-cultural researchinvolves studying a particular behavior (e.g., gender, facial expressions) across different cultures. If the behavior is found to be similar across cultures, psychologists conclude that differences in behavior are biologically (i.e., nature) based.

Holismvs.reductionism

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.

Are the research methods used scientific?

The biological approach uses very scientific methods such as scans and biochemistry. Animals are often used in this approach as the approach assumes that 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).

In other words, if heredity (i.e., genetics) affects a given trait or behavior, then identical twins should show a greater similarity for that trait compared to fraternal (non-identical) twins.

There are two types of twins:

Research using twin studies looks for the degree of concordance (or similarity) between identical and fraternal (i.e., non-identical) twins. Twins are concordant for a trait if both or neither of the twins exhibits the trait. Twins are said to be 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.

Thus, 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 which compared the IQ of family members. The correlation figures below represent the average degree of similarity between the two people (the higher the similarity, the more similar the IQ scores).

However, there are methodological flaws that reduce the validity of twin studies. For example, Bouchard and McGue included many poorly performed and biased studies in their meta-analysis.

Methods of Studying the Brain

It is important to appreciate that thehuman brainis 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.

Children begin to plan activities, make up games, and initiate activities with others. If given this opportunity, children develop a sense of initiative and feel secure in their ability to lead others and make decisions.

1. Neuro Surgery

We know so little about the brain and its functions are so closely integrated that brain surgery is usually only attempted as a last resort.

H.M.suffered such devastating epileptic fits that, in the end, a surgical technique that had never been used before was tried out.

This technique cured his epilepsy, but in the process, the hippocampus had to be removed (this is part of thelimbic systemin the middle of the brain.)

Afterwards, H.M. was left with severe anterograde amnesia. I.e., He could remember what happened to him in his life up to when he had the operation, but he couldn’t remember anything new. So now we know thehippocampusis involved in memory.

2. Electroencrphalograms (EEGs)

This is a way of recording the electrical activity of the brain (it doesn’t hurt, and it isn’t dangerous). Electrodes are attached to the scalp, and brain waves can be traced.

EEG

3. Brain Scans

More recently, methods of studying the brain have been developed using various types of scanning equipment hooked up to powerful computers.

The CAT scan (Computerised Axial Tomography) is a moving X-ray beam which takes “pictures” from different angles around the head and can be used to build up a 3-dimensional image of which areas of the brain are damaged.

Even more sophisticated is the PET scan (Positron Emission Tomography) which uses a radioactive marker as a way of studying the brain at work.

The procedure is based on the principle that the brain requires energy to function and that the regions more involved in the performance of a task will use up more energy. What the scan, therefore, enables researchers to do is to provide ongoing pictures of the brain as it engages in mental activity.

These (and other) methods for producing images ofbrain structure and functioninghave been extensively used to study language and PET scans, in particular, are producing evidence that suggests that the Wernicke-Gerschwind model may not after all be the answer to the question of how language is possible.

Timeline

Harlow (1848):Phineas Gagebrain injury case studyprovides neuroscience with significant information regarding the working of the brain.

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.

Edward Wilson (1975) published his book,Sociobiologywhich brought together an evolutionary perspective to psychology.

Critical Evaluation

Charles Darwin proposed the theory of natural selection. He 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.

However, describing behavior solely in terms of either nature or nurture is limiting, and attempts to do this underestimate the complexity of human behavior. It is more likely that behavior is due to an interaction between nature (biology) and nurture (environment).

A strength of the biological approach is that it provides clear predictions, for example, about theeffects of neurotransmittersor the behaviors of people who are genetically related. This means the explanations can bescientifically tested, replicated, and peer-reviewed.

A limitation is that most biological explanations arereductionist. 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.

Furthermore, it could be argued that the biological abnormalities seen in mental disorders could be the result rather than the cause of the disorder as the brain is a plastic organ that changes with the way we use it, so it could be that, for example, the damage seen in the caudate nucleus is the result of anxiety rather than its cause.

Additionally, it could be argued that the unbalance in neurotransmitters such aslow serotonin, in a depressed individual is the consequence rather than the cause of depression because the brain is a plastic organ that changes with the way we use it, so it could be that the depressed thinking causes the low level of serotonin observed.

Also, we usually do not find a 100% concordance rate in MZ twins for mental disorders, indicating that environmental and social factors must be involved in developing these disorders.

References

Bouchard, T. J., & McGue, M. (1981).Familial studies of intelligence: A review.Science, 212(4498), 1055-1059.

Harlow, J. M. (1848). Passage of an iron rod through the head.Boston Medical and Surgical Journal, 39, 389–393.

Wilson, E. (1975).Sociobiology: The New Synthesis. Harvard University Press

Further ReadingHow Experience Changes Brain PlasticitySex differences in the brainWhat has neuroscience ever done for us?Are Bigger Brains Better?BBC Radio 4: The influence of evolutionary theory, phrenology and a hole in Phineas Gage’s head.BBC Radio 4: Dr Bunn discusses the impact of neurology on how we understand ourselves today.

Issues and Debates#

Free will vs. determinism#

Nature vs. nurture#

Holismvs.reductionism#

Idiographic vs. nomothetic#

Are the research methods used scientific?#

Investigation of Inheritance#

Methods of Studying the Brain#

1. Neuro Surgery#

2. Electroencrphalograms (EEGs)#

3. Brain Scans#

Timeline#

Critical Evaluation#

References#

Further Reading#