Biological Approach In Psychology

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. 

All Behaviour Has a Biological Basis

Nervous System:

The structure of organs like the brain, central nervous system (CNS), peripheral nervous system (PNS), and the endocrine system are believed by biological psychologists to determine behaviour.

Behaviour is controlled by neuronal action, such as eating or breathing.

Case studies, like that of Phineas Gage, are used to demonstrate the influence of biological structures (e.g., frontal cortex) on behaviour (e.g., inhibition)

Brain:

The brain is central to consciousness and controls voluntary and involuntary movements and bodily functions.

It communicates with the body through the nervous system.

Specific areas of the brain are linked to general functions, for example, the occipital lobe with visual perception and the parietal lobe with sensory information processing.

Biological psychologists study how the structure and function of the brain relate to behaviour.

Neurochemistry:

Chemicals like neurotransmitters transmit signals between neurons at synapses.

Imbalances in neurotransmitters are associated with atypical behaviour, such as low serotonin (mood) linked to depression or aggressive behaviour, and high dopamine (reward) associated with schizophrenia.

Hormones, released by the endocrine system, organise the nervous system and body tissues and activate behaviours such as alertness, sleepiness, sexual behaviour, concentration, aggressiveness, and reaction to stress.

Hormones can influence behaviour, for example, high testosterone levels are associated with defensiveness and territoriality.

Genetics:

The biological approach posits that genes, which carry information in the form of DNA, are passed down through generations and carry instructions for characteristics, including some behavioural or psychological traits.

Genetic makeup is referred to as genotype, while phenotype is the expression of genes, influenced by both genetic inheritance and interaction with the environment.

Heritability measures how strongly differences among individuals for a trait are related to differences among their genes.

Twin studies seek to quantify the genetic contribution to a wide range of human traits and behaviors by comparing individuals with varying degrees of genetic relatedness raised in similar or different environments.

Research of identical (MZ) and non-identical (DZ) twins, has provided evidence suggesting a genetic component to psychological conditions like schizophrenia and depression.

Psychological researchers study genetics to better understand the biological basis contributing to certain behaviours, acknowledging that while humans share biological mechanisms, we are unique, and these mechanisms are expressed in a wide variety of behaviours, thoughts, and reactions

Some Human Behaviours Are the Result of Evolution and Natural Selection

The biological approach, particularly through evolutionary psychology, assumes that some human behaviours are adaptations that have evolved over time.

These behaviours, influenced by genetics, are seen as having provided an evolutionary advantage, maximising chances of survival and reproduction, and thus have been ‘naturally selected’ and inherited across generations.

This perspective originates with Charles Darwin’s theory of evolution by natural selection.

Evolutionary psychology seeks to understand the ultimate biological causes of behaviour, viewing behaviour like any anatomical characteristic as demonstrating adaptation to surroundings, including the physical and social environment.

Research in this area empirically tests predictions about psychological adaptations, such as preferences for food, habitat, or mates, or traits that improve group living like cooperation or detecting frauds.

Studies comparing mate selection preferences across cultures, for example, are presented as evidence for evolved traits promoting reproductive success.

1.  

The laws of behavior are the same for all species and knowledge gained by studying rats, dogs, cats and other animals can be generalized to humans

Methods Used in Biological Psychology

1. Genetic Studies and Twin Studies

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:

• 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 (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.

Twin studies have shown that genetic influence varies significantly across different traits. For example:

• Height: Has a high genetic influence, around 90% (0.9).
• General Mental Ability (IQ): Is estimated to be influenced by genetic factors by about 50% to 70%, closer to 70% according to more recent studies. Mean correlations for IQ in identical twins across multiple studies are around 0.73, suggesting about three-quarters of general ability is genetically influenced.
• Personality Traits (e.g., extroversion, sociability): Show a genetic influence of around 50% (0.5). Personality similarity between identical twins raised apart and those raised together did not differ, suggesting personality similarity to family is due to shared genes, not the shared environment of growing up together.
• Other Traits: Genetic influence has also been found for traits like sexual orientation, vocational interests, job satisfaction, migraine headaches, diet preferences, and whether someone is a morning or evening person. Dental health (cavities, appearance, missing teeth) and periodontal disease also show significant genetic effects (around 50% for periodontal disease).

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).

• 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

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.

Also, 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.

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.

EEGs have been used to study sleep, and it has been found that during a typical night’s sleep, we go through a series of stages marked by different patterns of brain wave.

One of these stages is known as REM sleep (Rapid Eye Movement sleep).

During this, our brain waves begin to resemble those of our waking state (though we are still fast asleep) and it seems that this is when we dream (whether we remember it or not).

3 . Brain imaging (MRI, PET, EEG)

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

For example, brain imaging fMRI and PET scans map areas of the brain to cognitive function, allowing the processing of information by centers in the brain to be seen directly.

Such processing causes the area of the brain involved to increase metabolism and “light up” on the scan.

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 of brain structure and functioning have 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.

4. 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 the limbic system in 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 the hippocampus is involved in memory.

Critical Evaluation

Limitations

A significant limitation of the biological approach is its reductionist perspective, simplifying complex behaviors to purely biological factors.

By reducing behavior to genetics, neurotransmitters, or brain structures alone, the biological approach neglects important psychological, social, and cultural influences.

For instance, the biological explanation of depression focuses primarily on neurotransmitter imbalance (low serotonin), ignoring cognitive factors like negative thinking patterns, life stressors, or social isolation.

The implications of this reductionism are negative. It can lead to incomplete understanding and treatments that may overlook crucial psychological or environmental causes.

Patients may be given medication to correct neurochemical imbalances without addressing underlying cognitive or social factors, potentially limiting treatment effectiveness and overlooking comprehensive, holistic interventions.

Another limitation of the biological approach is its deterministic view, suggesting behavior is entirely governed by biological factors beyond personal control.

Biological determinism argues behaviors result solely from genetic makeup, brain structure, or biochemical imbalances, implying limited individual agency.

For instance, attributing aggressive behavior strictly to genetic predisposition could lead individuals to disclaim personal responsibility.

The consequences are negative, as this perspective may undermine personal accountability, discourage behavioral change efforts, and potentially affect legal responsibility and treatment adherence.

Thus, biological determinism risks socially and ethically problematic outcomes.

The biological approach frequently struggles to establish definitive causal relationships.

Much biological research, particularly neuroimaging or genetic studies, is correlational.

For instance, brain abnormalities observed in individuals with OCD (caudate nucleus issues) could either cause OCD symptoms or result from prolonged symptoms (reverse causality).

The consequence of this limitation is negative, reducing clarity about cause-effect relationships.

Misinterpreting correlational data may lead to incorrect conclusions about treatments, which might target symptoms rather than underlying causes.

Research in biological psychology often lacks ecological validity due to controlled laboratory environments.

Highly controlled settings, such as brain scans conducted in artificial laboratory conditions, may not reflect natural brain activity.

Participants might behave differently in unnatural, experimental conditions, distorting true biological responses (e.g., exaggerated stress reactions measured in a laboratory rather than real life).

This negative implication limits generalisability, potentially making biological findings less relevant to everyday life contexts.

Treatments or theories developed from these studies might be less effective when applied in real-world environments.

A practical limitation is that treatments developed from biological explanations often carry significant side effects.

Psychotropic medications, although beneficial, can have substantial side effects, including addiction, withdrawal symptoms, emotional blunting, or physical health impacts.

For example, antipsychotic medications can lead to weight gain, diabetes, or motor dysfunction.

The consequence is negative, as these side effects can deter patients from continuing treatment, reduce quality of life, and sometimes make the biological treatment less beneficial overall.

This highlights the necessity of balanced approaches, integrating biological treatments with psychological or behavioral support.

Strengths

A major strength of the biological approach in psychology is its use of highly scientific and objective research methods.

Methods such as brain imaging techniques (fMRI, PET), biochemical tests, and controlled laboratory experiments provide quantitative, objective data.

This reduces researcher bias and increases reliability.

For example, studies using fMRI to measure brain activity, such as investigating amygdala responses related to emotional memory (Canli et al.), have produced replicable findings.

The consequence of employing scientific methods is positive. It strengthens the validity of biological explanations, allows replication, and enhances psychology’s credibility as a scientific discipline.

Thus, biological psychology’s findings are widely respected and practically applied, for example, in developing pharmacological treatments for disorders like depression or OCD.

Another strength of the biological approach is its practical real-world applications, particularly in treating psychological disorders.

By identifying biological factors such as neurotransmitter imbalances (e.g., serotonin deficiency in depression), effective pharmacological treatments such as antidepressants (SSRIs) can be developed.

For instance, SSRIs have been effectively used to manage symptoms of OCD, depression, and anxiety.

The consequence of this practical approach is highly positive, as it provides effective symptom management and relief to sufferers.

This significantly enhances patients’ quality of life and demonstrates the biological approach’s tangible impact on healthcare.

The biological approach effectively integrates with cognitive psychology through cognitive neuroscience.

Cognitive neuroscience merges biological and cognitive approaches, using brain imaging to verify cognitive theories empirically.

For instance, brain scans during memory tasks empirically confirm cognitive theories about memory encoding.

The consequence is positively significant, as it enables a more complete understanding of psychological phenomena, bridging gaps between cognitive theories and biological evidence, enhancing interdisciplinary collaboration.

Issues and Debates

Free will vs. determinism

The biological approach is strongly deterministic, meaning it views human behavior as entirely driven by biological processes (such as genetics, brain chemistry, and brain structure) over which individuals have little or no personal control.

For example, attributing depression primarily to genetic inheritance or neurotransmitter imbalances (like low serotonin levels) illustrates biological determinism.

This perspective implies individuals have limited personal agency over their behavior or mental health, raising important ethical considerations about personal responsibility and autonomy.

Nature vs. nurture

The biological approach largely emphasizes the nature side of the nature vs. nurture debate, highlighting genetic and biological factors as primary determinants of behavior.

However, modern biological psychology also acknowledges the significance of environmental influences.

For example, the brain is recognized as a plastic organ – meaning it continually changes and adapts through life experiences, interactions, and learning.

Thus, while biological psychologists believe genes set the potential for certain traits (genotype), they recognize that how these traits are actually expressed (phenotype) depends significantly on environmental interactions.

A clear illustration is temperament: individuals may inherit a genetic predisposition to certain personality traits (like introversion or extraversion), but life experiences, parenting, socialization, and culture shape how these traits develop and manifest.

This demonstrates a nuanced understanding—that behavior always emerges from complex gene-environment interactions, highlighting a reciprocal relationship between nature and nurture.

Holism vs. reductionism

The biological approach is often criticized as reductionist because it attempts to simplify complex behaviors into explanations solely based on genetics, biochemical processes, or neurological functioning.

For instance, the biomedical explanation for obsessive-compulsive disorder (OCD) tends to focus narrowly on genetic predisposition, neurotransmitter imbalances (such as serotonin deficits), or abnormalities in specific brain structures.

This biological reductionism overlooks other influential factors – such as early childhood experiences, conditioning (learning from rewards or punishments), cognitive processes (such as irrational beliefs), or socio-cultural contexts -that significantly impact psychological disorders and human behavior in general.

While reductionism allows precise scientific investigation of specific biological mechanisms, it risks oversimplifying and missing the broader, holistic understanding of behavior.

Idiographic vs. nomothetic

The biological approach generally adopts a nomothetic perspective, meaning it seeks universal laws and general principles that apply broadly across all humans.

It operates on the assumption that humans share fundamental physiological processes (like neural transmission, genetic inheritance patterns, and brain functions).

By investigating these shared biological mechanisms through large-scale studies, biological psychologists aim to identify predictable patterns of behavior.

For example, research into the role of neurotransmitters such as serotonin in mood regulation is based on the belief that these biological processes universally influence emotional experiences across human populations.

Are the research methods used scientific?

Research methods within the biological approach are notably scientific and empirical, involving rigorous and objective techniques such as neuroimaging scans (e.g., MRI, PET scans), genetic testing, biochemical analysis, and laboratory experiments.

These methods allow precise, quantifiable observations and facilitate repeatability, increasing the credibility of biological research findings.

Moreover, the biological approach frequently uses animal studies, justified by the assumption that humans and animals share many fundamental physiological processes.

Studying animals provides greater control over experimental conditions and can ethically enable biological manipulations impossible with human participants, although this raises ethical considerations regarding generalizability and animal welfare.

Timeline

1. The Voyage of the Beagle (1805 – 1836) – Darwin formulated his theory of natural selection by observing animals while traveling the world.
2. Harlow (1848): Phineas Gage brain injury case study provides neuroscience with significant information regarding the working of the brain.
3. 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.
4. 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.
5. Edward Wilson (1975) published his book, Sociobiology which brought together an evolutionary perspective to psychology.
6. The birth of Evolutionary Psychology begins with the publication of an essay, The Psychological Foundations of Culture, by Tooby and Cosmides (1992).

References

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

Darwin, C. (1859). On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (1st ed.). London: John Murray.

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

Tooby, J., & Cosmides, L. (1992). The psychological foundations of culture. In J. Barkow, L. Cosmides, & J. Tooby (Eds.), The adapted mind: Evolutionary psychology and the generation of culture. New York: Oxford University Press.

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