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What is psychology? Theories, evidence and explanations

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Psychology is the scientific study of the mind and behaviour. It asks why people think, feel and act as they do, and then tests the answers with evidence.

Mind and behaviour

Behaviour is anything a person does that can be observed, such as helping someone, remembering a list or obeying an order.
The mind covers what we cannot see directly: thoughts, feelings, memories and beliefs.
Psychologists study both, but they can only measure the mind through behaviour, for example by counting how many words someone recalls.

Theories and studies

A theory is an explanation of behaviour, for example Piaget's theory that children think in stages.
A study (or piece of research) collects evidence to test a theory, for example the three mountains task.
At GCSE you will learn theories, then the key studies that support or challenge them, and you will judge how good both are.
In KS3 science you learned the same cycle: an idea, a prediction, a test, then a conclusion.

Different kinds of explanation

The same behaviour can be explained in different ways:
Biological: genes, brain areas and chemicals in the brain (for example the 5-HTT gene and depression).
Psychological: thoughts, learning and experiences (for example negative thinking and depression).
Social: other people and the situation (for example obeying a person in uniform).
A big GCSE debate is nature (what we inherit) versus nurture (what we experience).
Worked example

Maya is afraid of dogs. Her mum is too, and Maya often saw her mum scream when a dog came near. Is this a nature or nurture explanation?

  1. Maya has learned the fear by watching her mum.
  2. Learning from experience and other people is nurture, not inherited.

Answer: Nurture: Maya learned the fear by observing her mum's behaviour.

Key idea

Psychology is the scientific study of the mind and behaviour. Theories explain behaviour; studies collect evidence to test them. Explanations can be biological, psychological or social, and the nature versus nurture debate asks whether behaviour is inherited or learned.

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