Biological psychology, also known as physiological psychology, delves into the biology underlying behaviour, centring on the nervous system, hormones, and genetics. It explores the intricate interplay between the mind and body, investigates neural mechanisms, and scrutinizes how heredity shapes behaviour.

Historical development

While the current consensus regards the mind and brain as interchangeable terms, philosophers and psychologists engaged in lengthy deliberations on the mind/body problem. Philosophers and other intellectuals pondered the nature of the relationship between the realm of the mind and that of the physical world.¹

However, this debate isn't confined to history alone. It persists as a significant subject in contemporary psychology and neuroscience. It explores the mechanisms by which the subjective experiences of the mind, encompassing emotions and thoughts, are intertwined with or emerge from the physical processes of the brain and body.

Assumptions

• Psychology should be viewed through a scientific lens, studied typically in laboratory settings.
• Cognitive processes and behaviour can be elucidated by biological factors, such as genes and the nervous system.
• Human genes have undergone millions of years of evolution to adapt behaviour to the environment.
• Behavioural patterns may be heritable, suggesting that most behaviours serve an adaptive or evolutionary purpose.
• Human similarity to animals allows for research to be conducted on both humans and animals.
• Psychology adheres to a nomothetic approach, concentrating on formulating laws and theories concerning the impacts of physiological and biochemical processes applicable to all individuals.

Biological foundations

The brain and nervous system:

The central nervous system (CNS) comprises the brain and spinal cord. The cerebral cortex, the outer layer of the brain, plays a pivotal role in cognition, sensation, motor skills, and emotions.

The brain consists of four lobes:

• Frontal lobe: Involved in motor skills, higher-level cognition, and expressive language.
• Temporal lobe: Interprets sounds and language, memory processing, and other functions.
• Parietal lobe: Processes tactile sensory information such as pressure, touch, and pain, among other functions.
• Occipital lobe: Responsible for interpreting visual stimuli and information.
• The motor (efferent) division connects the CNS to muscles and glands.
• The sensory (afferent) division transmits sensory information to the CNS.

Another essential component is the autonomic nervous system, which regulates involuntary processes like heart rate, breathing, and blood pressure. It comprises two divisions:

• The parasympathetic nervous system: Promotes a return to rest and regulates functions like digestion.²
• The sympathetic nervous system: Initiates the "fight or flight" response, preparing the body to respond to danger or stress.

Neurotransmitters

Neurotransmitters serve as chemical messengers facilitating the transmission, enhancement, and regulation of signals between neurons, also referred to as nerve cells, and target cells across the body. These target cells may include glands, muscles, or other neurons. They facilitate the transmission of information between neurons, allowing for the exchange of chemical messages between the body and the brain.

Various neurotransmitters exert distinct effects on the body. For instance, dopamine, a neurotransmitter, is implicated in movement and learning. Abnormal levels of dopamine have been linked to psychological disorders like schizophrenia, whereas insufficient dopamine is associated with Parkinson’s disease.³

Biopsychologists analyze different neurotransmitters to discern their impact on human behaviour. This understanding aids researchers in unravelling the underlying causes of mental health conditions and in developing novel treatments.

Tests employed in biological psychology:

In the study of the human brain and nervous system, researchers employ various tests. Brain imaging techniques are frequently employed to monitor brain activity while individuals participate in various motor, cognitive, and perceptual tasks. These techniques can be broadly classified into two categories: those examining the brain's electrical activity and those monitoring changes in blood flow within brain regions associated with activity. Two commonly utilized methods are:

fMRI: Functional magnetic resonance imaging (fMRI) entails brain scanning to assess blood flow, gauging blood oxygenation and flow patterns. Increased blood flow and oxygenation within a brain region signify heightened activity levels.⁴

EEG: Electroencephalography (EEG) is employed to record electrical currents on the brain's surface, enabling the monitoring of activity levels and the identification of shifts in consciousness.⁵  By utilizing EEG, researchers can observe event-related potentials (ERPs), indicative of spikes in activity correlated with specific stimuli or cognitive processes.

Criticism 

Biological psychology offers strengths in its ability to yield precise predictions, such as forecasting the impacts of neurotransmitters or the behaviours of genetically related individuals. This lends itself to scientific scrutiny, replication, and peer review. However, a notable limitation of the biological perspective lies in its tendency toward reductionism. By predominantly attributing behaviour to genetic and biological processes, it overlooks the significant influences of upbringing, social interactions, and cultural environments. Consequently, biological explanations may lack comprehensive insight into human behaviour. Additionally, it can be argued that the biological abnormalities observed in mental disorders might be outcomes rather than causes of the disorders. Considering the brain's plasticity, alterations in structures like the caudate nucleus could potentially result from conditions such as anxiety rather than solely serving as their origin.

Summary

Biological psychology, also known as physiological psychology, explores the biological basis of behaviour, focusing on the nervous system, hormones, and genetics. It delves into the complex interaction between the mind and body, investigating neural mechanisms and the influence of heredity on behaviour. 

Despite historical debates, the relationship between the mind and the physical world remains a key topic in contemporary psychology and neuroscience, examining how subjective experiences arise from brain and bodily processes. Assumptions in biological psychology include the scientific study of psychology, the role of biological factors in behaviour, and the adaptive nature of human behaviour shaped by evolution. Biological foundations in biological psychology include the central nervous system comprising the brain and spinal cord, with the cerebral cortex governing cognition, sensation, motor skills, and emotions.  

Additionally, neurotransmitters act as chemical messengers that facilitate communication between neurons, impacting behaviour. For example, dopamine influences movement and learning, with abnormal levels associated with mental disorders like schizophrenia and Parkinson's disease. Biopsychologists study neurotransmitters to understand their effects on behaviour and develop treatments for mental health conditions. Brain imaging techniques such as fMRI and EEG enable the monitoring of brain activity during various tasks.

The strengths of biological psychology include its ability to make precise predictions about the effects of biological factors on behaviour. However, it has limitations, such as reductionism and overlooking the influence of social and environmental factors on behaviour. 

Additionally, biological abnormalities observed in mental disorders may be outcomes rather than causes, considering the brain's plasticity and the potential for structural changes due to environmental factors.