Experiments

Question 1

What is the experimental design

Answer 1

Refers to the way in which participants are arranged in relation to the different experimental conditions

Question 2

Independent groups design

Answer 2

Participants only take part in one condition of the experiment (2 separate groups)
✅ no order effects (practice, fatigue, boredom) as participants only tale part in one condition
✅ less chance of demand characteristics
❌ less economical as twice as many participants needed
❌ any differences between conditions could be due to participant variables - control by randomly allocating to groups

Question 3

Repeated measures design

Answer 3

Participants take part in both conditions of the experiment (1 group)
✅ any differences between conditions are likely to be due to changes in the IV and not due to participant variables
✅ fewer participants needed to be recruited as they are used twice
❌ Order effects may occur (eg. Practice, fatigue, boredom) as participants take part in all conditions
❌ may see more demand characteristics

Question 4

Matched pairs design

Answer 4

Participants are matched on variables relevant to the experiment eg, IQ, gender. One participant from each pair are then allocated to a different condition
✅ no order effects
✅ participant variables are reduced as participants have been matched
❌ time consuming and expensive to match participants
❌ participants can never be matched exactly

Question 5

Order effects

Answer 5

Carrying out a task repeatedly leads to changes in performance
- boredom effect: deterioration of performance across conditions as participants become tired and bored
- practice effect: improvement across conditions through familiarity of the task or environment
This is a problem with repeated measures design
- leave a long gap between conditions
- use independent groups or matched pairs
- counterbalanced design

Question 6

What is counterbalancing

Answer 6

A method used to deal with order effects that arise when using a repeated measures design
The sample is split in half with one half completing the two conditions in one order and the other half completing the conditions in the reverse order. Eg, the first 10 participants would complete condition A followed by condition B but the remaining 10 participants would complete condition B then A.
Any order effects should be balanced out by the opposing half of participants

Question 7

What are the types of experiments

Answer 7

• laboratory
• field
• natural
• quasi

Question 8

What is a laboratory experiment

Answer 8

Involves the manipulation of an IV and conducted under highly controlled conditions. A laboratory is any environment where variables can be controlled

Question 9

What is a field experiment

Answer 9

Involves the manipulation of an IV but the experiment is conducted in the field’ / a real world situation. Participants are often unaware that they are being studied.

Question 10

What is a natural experiment

Answer 10

The researcher takes advantage of a pre-existing IV which would have changed even if the experimenter was not studying it. Participants may be tested in the field or lab

Question 11

What is a quasi experiment

Answer 11

Have an IV that is based on an existing difference between people eg. Age or gender. No one has manipulated this variable it simply exists