To introduce psychology as a research enterprise. The scienti c study of behaviour, thought, and experience, and how they can be affected by physical, mental, social and environmental factors. Thinking of the most well known object. Testing: colour/ tool decision following calculations or just the colour/ tool decision. Given a chance to think about it, person might deliberately avoid saying the rst colour/ tool that comes to mind. Encouraging speedy decisions on calculations prevents overthinking on colour/ tool decision. Testing: emphasize the speedy decisions, emphasize accurate calculations which encourages overthinking on colour/ tool decision. Preceding colour/ tool question with norm information (98% of people say the same thing) causes people to ask: what would other people say? . Trying to go against the norm and to come up with something different and unique. Testing: manipulate the percentage numbers (50/50) so either way you"re seen as normal. Common sense is not suf cient enough to understand and predict behaviour.