Research Method

Independent Variable

the variable that is manipulated/changed

Dependent Variable

what is observed

Controlled Variables

what stays the same, kept constant to avoid influencing IV/DV

Extraneous Variables

any variable that isn’t IV and could potentially have an effect on DV

Confounding Variable

a specific type of extraneous variable that does affect the results of the experiment. distorts the results

Operationalisation

turning the variables into something that can be measured

Null Hypothesis

predicts no relationship between variables

Alternative Hypothesis

predicts a relationship between the variables

What is a lab experiment?

done under highly controlled conditions

What is a field experiment

IV is manipulated, but done in a natural setting

True Experiment

IV is manipulated to see how DV is affected, random allocation

What is a quasi experiment

no random allocation, groups set apart by traits

What is a natural experiment?

no IV manipulation, studying the result of a “naturally occurring event”

Target Population

the group of people that the psychologists want to study

Sample

group of people from the target population that are participants in an experiment

Probability Sampling

method that relies on random selection everyone in target population has a chance of being selected

Non-Probability Sampling

participants are not randomly selected, but are chosen based on other criteria. Not everyone has chance of selection

Self Selected Sampling

Aka. volunteer sampling Participants volunteer to be a part of sample

Opportunity Sampling

Aka. convenience sampling. Researchers choose participants based on convenience

Purposive Sampling

Looking for very specific set of traits, sampling with a purpose. Participants selected based on predetermined criteria

Snowball Sampling

Aka network sampling. A type of purposive sampling where researchers are looking for specific people. Participants who are already in the study, help the researcher to recruit more participants through their social network

Simple Random Sampling

Everyone in the target population has an equal change of being chosen. The ideal sampling technique

Stratified Sampling

Attempts to make a more representative sample by having it reflect the sub-groups of the target population

Independent Measures

participants allocated to one condition of the experiment

Within Subject (Repeated Measures) 

participants are exposed to all conditions of the experiment

Matched Pairs 

participants are paired with another participant sharing similar characteristics, but each is exposed to only one condition of the experiment

Random Assignment

when participants have an equal chance of being allocated to either the experimental or the control group within a study

Ethical Considerations (CARDUD)

informed consent, anonymity, right to withdraw, deception, undue stress or harm, debriefing

Internal reliability 

how consistently something is measured within itself

External reliability

how consistently something is measured in replications by other independent researchers

Internal validity

extent to which it can be claimed that research outcomes are a result of the experimental treatment

External validity

extent to which it can be generalised

Population validity

how well the sample can be used to generalize the entire population

Ecological validity

degree to which the experiment’s condition match real life

Construct validity

how effectively psychological constructs are operationalised or made measurable within a study

Sampling bias

when the sample isn’t chosen properly and isn’t representative of target population

Self-selection bias 

participants selecting themselves or volunteering for research have different characteristics than people who wouldn’t volunteer, not really representative of the population

Undercoverage bias 

important subgroups in the population are not selected as part of the sample, ot representative and results may be distorted

Participant Bias

the tendency of participants to act the way they think the researcher wants them to act, not doing what they naturally would

Social desirability effect

where participants responds in such a way that the researcher has a good impression of them