In the broadest of terms, psychology is the scientific study of the mind and behaviour, and compared to many of the other sciences, it is one of the most modern and is certainly the most progressive. 150 years ago, psychology was structured in two core theoretical forms: Structuralism and Functionalism.

Structuralism was a theoretical approach developed by Wilhelm Wundt, focused on breaking down mental processes into basic components. However, while Structuralism relied on trained introspection, this was proven to be unreliable.

In disagreement with Structuralism, William James, an American psychologist created a theoretical approach named Functionalism. With the mind constantly changing and developing, James found that studying the structure of the conscious experience was pointless. Instead, he proposed that the focus should be on how and why an organism does something.

Since the development of both Structuralism and Functionalism, psychology has developed and moved on, with several other dominant and influential approaches taking their place. Subsequently, figureheads of psychology have all created forward-thinking theories, such as Freud, Jung, Adler, Erikson and Kuhn.

Psychology now has 5 unique and core sub-fields that we will explore below.

Developmental Psychology

This scientific approach aims to explain growth, change and consistency through a lifespan by looking at how thinking, feeling and behaviour change throughout a person's life.

Commonly, the vast majority of theories within Developmental Psychology focus on the period of life where most changes occur in childhood. Therefore, it is a Developmental Psychologist's standpoint to study theoretical areas such as biological, social, emotional, and cognitive processes.

Health Psychology

This scientific branch is dedicated to untangling community and environmental elements' effects on general health and illness rates. Mainly exploring health conditions that are largely linked to the psychological science of their inner workings. With psychology at hand, it aims to prevent illness and help people develop healthier lifestyles that boost their overall experiences. This led to the sub-field study of Sports Psychology, too.

Health Psychology is one of the youngest subfields of the science, one of the most rapidly expanding and most interesting to study.


Often perceived to be the ‘rocket-scientist' strand of the field of psychology, Neuropsychology is the theoretical work that analyses how the brain and the rest of the nervous system influence a person's cognition and behaviours and the impact that injuries and neuro-illnesses have on cognition. With this knowledge, new behaviours can be learnt to unlearn unhelpful habits and patterns from past traumas.

Neuropsychology also closely informs Criminal Psychology, as understanding the motivations for a person's crime is closely linked to their cognition.

Experimental Psychology

The common workplace of Experimental Psychologists has transitioned from private medical and pharmaceutical companies to research facilities in universities and government-led enterprises.

This experimentation typically uses human and animal subjects engaged in sensory, perception, memory, cognition, motivational and social testing to prove, in practice, the theory behind psychological statements. Many people learn about the results of these experiments when taking A-level Psychology.

Industrial Psychology

Often called occupational psychology, Industrial Psychology is the science of human behaviour relating to work and applies psychological theories to humans in their work setting.

The objective of Industrial Psychology is to enable businesses to understand their workforce better. It gives businesses the capacity to ‘get more' out of their workforce. This is one of the most commercialised forms of psychology and can be one of the highest-earning subfields.

Psychology is a broad and ever-changing scientific field. Unlike many more traditional and aged forms of science, psychology is always evolving. The evolution of theory has led to the discovery that many prominent approaches are inaccurate decades after they were established. This ever shifting landscape makes it one of the most interesting social sciences to study, with great career opportunities.