Experimental Method

Question 1

What’s an aim?

Answer 1

• a general statement of what the researcher intends to investigate
• the purpose of the study
• when writing an aim, start with ‘to investigate’
• e.g. to investigate whether drinking energy drinks makes people more talkative

Question 2

What’s a hypothesis?

Answer 2

• a clear, precise, testable statement that states the relationship between the variables being investigated
• a prediction of what the outcome will be
• written in present or future tense
• this is an experimental/alternative hypothesis

Question 3

What’s a directional hypothesis?

Answer 3

• a one-tailed hypothesis which states which way you believe the study is going to go
• e.g. people who drink energy drinks are more talkative than people who don’t drink energy drinks

Question 4

What’s a non-directional hypothesis?

Answer 4

• a two-tailed hypothesis which only states that there will be a difference between the two conditions
• doesn’t specify the nature of the difference
• e.g. there will be a difference in talkativeness between people who drink energy drinks and people who don’t drink energy drinks

Question 5

What’s a null hypothesis?

Answer 5

• states that there is no difference or relationship between the two variables
• e.g. there will be no difference in talkativeness between those who drink energy drinks and those who drink water

Question 6

When do we use a directional hypothesis?

Answer 6

• when we have previous research to support our hypothesis

Question 7

When do we use a non-directional hypothesis?

Answer 7

• when there is no previous research to support either hypothesis, or the research is inconsistent

Question 8

What’s an independent variable (IV)?

Answer 8

• the variable that is manipulated by the researcher

Question 9

What’s a dependent variable (DV)?

Answer 9

• the variable that the researcher measures
• all other variables that could potentially affect the DV should be controlled

Question 10

What are ‘conditions’?

Answer 10

• the different testing groups which reflect what the independent variable is
• control condition (no energy drink/drinking water)
• experimental condition (energy drink)

Question 11

What’s operationalisation of variables?

Answer 11

• clearly defining variables into measurable
• variables are ‘operationalised’ when writing a hypothesis

Question 12

How do you write an operationalised hypothesis?

Answer 12

1. Directional or non-directional
2. Operationalise your IV and DV (identify variables)
3. Construct your hypothesis (include both conditions of the IV, and the DV, both operationalised)
4. Write in present or future tense

Question 13

What are extraneous variables?

Answer 13

• any other variables that might affect the DV
• not including the IV

Question 14

What are confounding variables?

Answer 14

• extraneous variables that have systematically changed with the IV
• e.g. one condition containing just extroverts and the other condition containing just introverts, by chance
• personality would therefore be a confounding variable which could explain changes in the DV

Question 15

What are demand characteristics?

Answer 15

• type of extraneous variable
• subtle cues within a study that could possibly reveal the purpose of the study to participants
• may lead to the participant changing their behaviour (please you/screw you effect)
• behaviour is no longer natural

Question 16

What are investigator effects?

Answer 16

• when the researcher, consciously or unconsciously, influences the outcome of the experiment
• e.g. researcher’s characteristics, researcher’s expectations, interaction with participants

Question 17

What’s randomisation?

Answer 17

• randomly allocating participants to conditions
• reduces bias

Question 18

What’s standardisation?

Answer 18

• consistent use of procedures and conditions for all participants in a study
• controlled environment and identical instructions
• minimises effect of extraneous variables

Question 19

What are the three experimental designs?

Answer 19

• repeated measures
• independent groups
• matched pairs

Question 20

Repeated Measures

Answer 20

• participants experience both conditions

Question 21

Repeated Measures Evaluation

Answer 21

STRENGTHS
- reduced participant variables (individual differences)
- requires less participants so more economical
- more direct comparisons

WEAKNESSES
- order effects
- demand characteristics
- more than one test needed

Question 22

Independent Groups

Answer 22

• participants only experience one condition

Question 23

Independent Groups Evaluation

Answer 23

STRENGTHS
- no order effects
- reduced demand characteristics
- only one test needed
- less time-consuming

WEAKNESSES
- participant variables
- less economical

Question 24

Matched Pairs

Answer 24

• pairs of participants matched in terms of key characteristics e.g. IQ, age
• one member of each pair placed into experimental group, other placed in control group

Question 25

Matched Pairs Evaluation

Answer 25

STRENGTHS - no order effects - reduced demand characteristics - less participant variables WEAKNESSES - still some participant variables as you can't match exactly - matching is time consuming

Question 26

What's counterbalancing?

Answer 26

- attempt to minimise order effects in a repeated measures design - half the participants do condition A, then B - the other half do condition B, then A

Question 27

What's random allocation?

Answer 27

- used in independent groups design - participants randomly assigned to conditions using random techniques e.g. coin flip, picking names out of a hat - reduces participant variables - avoids bias - evenly distributes participant characteristics across the conditions

Question 28

What are the four types of experiment?

Answer 28

- Lab - Natural - Quasi - Field

Question 29

Lab Experiments

Answer 29

- highly controlled environment - investigator manipulates the IV STRENGTHS - control over extraneous variables - cause and effect (IV has affected DV) - replicable WEAKNESSES - low external validity (artificial) - low ecological validity (can’t generalise) - demand characteristics - tasks don’t represent everyday life

Question 30

Natural Experiments

Answer 30

- investigator can’t manipulate the IV e.g. natural disaster STRENGTHS - high external validity WEAKNESSES - naturally occurring event reduces the opportunities for research - hard to generalise

Question 31

Field Experiments

Answer 31

- everyday, natural environment - investigator still manipulates the IV STRENGTHS - more realistic setting - behaviour is more natural and authentic - high external validity WEAKNESSES - less control over extraneous variables - cause and effect is more difficult to establish - precise replication not possible - ethical issues (informed consent)

Question 32

Quasi Experiments

Answer 32

- IV based on an existing difference between people e.g. age, gender - can’t manipulate IV STRENGTH - control over extraneous variables WEAKNESSES - can’t randomly allocate participants to conditions - confounding variables

Question 33

What's a single-blind procedure?

Answer 33

- participant not told the aim of the study - participant not told what condition they’re in - attempt to control the effects of demand characteristics - at the end of the study, participants should receive a debrief

Question 34

What's a double-blind procedure?

Answer 34

- neither the participant nor the researcher know the aim of the study - a third party conducts the investigation without knowing its main purpose - important feature of drug trials

Question 35

What's a pilot study?

Answer 35

- small-scale study that takes place before the real investigation - can identify possible issues and modify the procedure