Psychology is a science, which means its claims must be tested with careful evidence rather than guesswork or opinion.
Ways to study behaviour
- Experiments: the researcher changes one thing and measures its effect, to test cause and effect.
- Observations: watching and recording behaviour, often without interfering.
- Samples: the group of people studied, chosen to represent a wider population fairly.
Correlation versus causation
A correlation means two things tend to change together, but this does not prove one causes the other. For example, ice-cream sales and swimming both rise in summer, yet ice cream does not cause swimming; the hot weather affects both. Psychologists must not confuse correlation with causation.
Research ethics
Studying people brings responsibility. Ethical research requires informed consent (people agree, knowing what will happen), keeping participants safe from harm, and respecting their right to stop at any time.
🕌 The Muslim pioneers
Ibn al-Haytham (965–1040) pioneered the experimental method. He taught that we should form a question, test it with careful, repeatable observation, and only accept what the evidence supports. This scientific method, questioning, testing and verifying, is exactly what psychology uses today to study the mind. His insistence on evidence over assumption laid foundations for all modern science.
Three ways to study behaviour
| Method | What the researcher does | What it can show |
|---|---|---|
| Experiment | Changes one thing and measures the effect | Cause and effect |
| Observation | Watches and records behaviour, often without interfering | What people really do, rather than what they say |
| Sample | Chooses the group to study so it represents the wider population fairly | Whether the findings can be trusted beyond the people tested |
Correlation is not causation
Ice-cream sales and swimming both rise together in summer. Ice cream does not cause swimming — hot weather causes both. A third factor is the usual explanation.
Which conclusions are safe to draw?
- These two things rise and fall together
- An experiment changed one thing and measured the effect
- A third factor may explain both
- One must be causing the other
- A correlation proves the cause