Research Methods Flashcards
Aim
General expression of what the research intends to investigate.
Independent variable
The aspect of the experiment that the researcher changes or manipulates.
Dependent variable
The data that the researcher measures.
The data should only be affected by the IV.
Extraneous variable
A variable other than the IV that might affect the DV so therefore should be controlled.
Hypothesis
A prediction or testable statement about what the researcher thinks will happen.
Operationalisation
- Operationalised variables are carefully stated, demonstrating exactly how they are to be measured.
- This makes the hypothesis testable and measurable.
- This is so that the target behaviour can be observed and recorded.
Null hypothesis
- Predicts that there is no difference or relationship between the two groups.
- If any difference is found it is due to chance.
Alternative hypothesis
Predicts a difference/relationship between groups/conditions.
Directional hypothesis (one tailed)
Predicts a difference/relationship between conditions and states the direction of the difference.
Non-directional hypothesis (two tailed)
Predicts a difference/relationship between conditions and doesn’t state the direction.
When do you use directional or non-directional hypothesis?
Previous research evidence - directional
No previous research that suggests which direction - non-directional
How to write a null hypothesis
There will be no difference in DV in IV1 compared to IV2.
How to write a directional hypothesis
Participants who IV1 higher/lower DV IV2.
How to write a non-directional hypothesis
There will be a difference in DV in IV1 compared to IV2.
Levels of IV
Numbers of conditions
Lab experiment
- Carried out in an artificial environment
- Controlled and standardised procedure
- Researcher manipulates the IV to measure the effect on the DV
- Participants know they’re taking part in a study
Field experiment
- Conducted in a more natural environment
- Researcher manipulates the IV to measure the effect on the DV
- Participants do not know they are in an experiment
Natural experiment
- Conducted in a natural environment
- The IV is naturally occurring
- IV: setting
Quasi experiment
- Either lab or natural
- IV: something that occurs within the person (a characteristic)
- Not true experiments because you cannot randomly allocate participants to conditions
Standardised procedure
- Ensuring that all participants are treated in exactly the same way.
- Allows for reliable methodology
Reliability
Consistency
Internal validity
The extent to which it was the IV alone that caused a change to the DV.
Ecological validity
The extent to which the results can be generalised to another setting (e.g real life).
Mundane realism
The extent to which the task is representative of that behaviour in the real world.
Demand characteristics
- Cues in the environment that may reveal the aim of the experiment, and so participants may change their behaviour as a result.
- ‘Please you’ effect - changing your behaviour to try and ‘help’ the researcher.
- ‘Screw you’ effect - changing your behaviour to go against what the researcher is trying to find.
Random allocation
Each participant has an equal chance of being put into either condition.
Order effects
An extraneous variable where the order in which conditions of the experiment take place effects the results (e.g practice effects or fatigue effects).
Lab experiments strengths (x2)
- High control of extraneous variables (increases internal validity)
- Replication is possible due to standardisation (can test if the findings are reliable)
Lab experiments limitations (x3)
- Artificial environment (low ecological validity)
- Artificial task (low mundane realism)
- People know they are being tested (demand characteristics)
Field experiments strengths (x2)
- Natural environment (higher ecological validity)
- Participants do not normally know they are in an experiment (reduction in demand characteristics)
Natural experiments strengths (x2)
- They provide opportunity for research that might not otherwise be undertaken for practical or ethical reasons
- They often have high ecological validity because they study real-life events
Natural experiments limitations (x3)
- Lack of controls (difficult to establish cause and effect)
- A naturally occurring event may not happen very frequently (reducing the opportunities for research)
- Participants may not be randomly allocated to conditions (you cannot be sure the IV is affecting the DV - reducing validity)
Quasi experiments strength
They are often carried out under controlled conditions (same strengths as lab experiments).
Quasi experiments limitation
The participants cannot be randomly allocated to conditions (there may be participant extraneous variables).
What is meant by experimental designs
How the participants are organised across the conditions.
Independent groups design
Each participant takes part in one condition only.
Random allocation - the lottery method (x3)
- Obtain a list of all the people in the sample
- Put all the names in a lottery hat
- Select the number of names required for condition A and put the next names into condition B
Random allocation - random number generator (x2)
- Number every member of the sample
- Use a computer program to to get a random number and allocate half into one condition
Matched pairs design
Each participant only takes part in one condition only, but the participants are matched on variables considered relevant (e.g age, sex, IQ).
How is a matched pairs design done? (x3)
- The researcher recruits a group of participants
- They match the participants on specific variables (such as age or IQ) often done with a questionnaire
- One of the pair gets randomly allocated into condition A, the other condition B
Repeated measures design
Each participant takes part in both conditions.
Independent groups strengths (x2)
- Order effects are reduced as participants only take part in one condition
- Demand characteristics are reduced (less likely to guess the aim of the study if only taking part in one condition)
Independent groups limitations (x2)
- Participant extraneous variables between the groups (lowers the internal validity)
- Less economical than repeated measures (need twice as many participants)
Repeated measures strengths (x2)
- Participant extraneous variables are controlled for (reduced, never fully eliminated)
- Less participants needed as they appear in both conditions
Repeated measures limitations (x2)
- Order effects
- Demand characteristics
Matched pairs strengths (x2)
- Reduced order effects and demand characteristics (participants only take part in one condition)
- Participant extraneous variables are reduced (not eliminated)
Matched pairs limitations (x2)
- The participants cannot be truly matched
- Time consuming and expensive, so less economical than the other designs
Fixing problems - independent groups
- Participant variables and researcher bias: use random allocation
Fixing problems - repeated measures
- Order effects: use counterbalancing (half do A then B, half do B then A)
Fixing problems - matched pairs
- Participant variables: restrict the number of variables to match on
Experimental realism
Whether an experiment has psychological impact and ‘feels real’ to participants.
Confounding variables
Variables apart from the IV that have affected the DV.
Difference between extraneous and confounding variables
Extraneous - could affect
Confounding - have affected
Uncontrolled variables
Variables that cannot be controlled for (e.g weather) - they will become confounding variables.
Situational confounding variable
Features of the experimental situation
Participant confounding variable
Differences between the participants
Investigator effects
Where a researcher (consciously or unconsciously) acts in a way to support their prediction.
This is particularly a problem when observing effects that can be interpreted in more than one way.
Examples of direct effects (x3)
- Non verbal communication
- Spending more time with one group
- Asking leading questions
Examples of indirect effects (x2)
- Operationalised variables are designed in such a way that the desired result is more likely
- Loose procedure effect: an investigator may not clearly state the standardised instructions which leaves room for the results to be influenced by the experimenter
Randomisation
Presenting any stimuli in an experiment in a ‘random’ manner to avoid it having an effect on the DV.
It reduces the chance of practice effects becoming a confounding variable.
Single blind test
Where participants do not know which condition of a study they are in.
Double blind test
When neither participant nor the investigators know which condition the participants are in.
Target population
The group of people the researcher wants to study.
They cannot study everyone so they have to select a sample.
Sample
A small group of people who represent the target population and who are studied.