Topic: Psychology- Types of experiments
Key points/ Notes/Diagrams:
Main Ideas/
Laboratory experiment- An experiment conducted in a highly controlled environment
Questions: where every variable can be carefully controlled. Researchers manipulate the IV and
record the effects of the DV. Researchers want to record the physiological effects of
What is a lab the participants and stimuli (e.g bright light, loud noise, electric shock).
experiment? - Highly controlled
- Can be easily replicated
What is a field - Confounding variables minimised (higher internal validity)
experiment? - Artificial situation (lack of generalizability and low external validity)
- Participants know that they’re in an experiment (demand characteristics)
What is a natural - Tasks participants are asked to carry out may not represent real life
experiment? experiments (low mundane realism)
What is a Quasi Field experiment- An experiment conducted where the IV is manipulated to a normal
experiment? everyday setting (e.g researchers tested if people were more likely to listen to a
person dressed up like a guard, milkman or normally).
What are the pros - Less artificial compared to lab experiments
and cons of each - Participants are usually unaware that they’re being studied
type of experiment? - Loss of control of confounding variables
- Ethical issues- participants unaware and they can’t give out consent/ lack of
What does internal privacy
and external validity
mean? Natural experiment- The researcher takes advantage of the naturally occurring IV,
therefore the researcher doesn’t manipulate the IV. (e.g the researcher could take
advantage of two different cultures that use different parenting styles and then
measure the differences in the future relationships of kids).
- Allows research where IV can’t be manipulated for ethical reasons
- Enables psychologists to study real problems (increased mundane realism
and ecological validity)
- A naturally occurring event may only happen rarely, reducing opportunities
for research and generalising findings to similar situations
- Cannot demonstrate a casual relationship because the IV is not directly
manipulated
Quasi experiment- Having IV that is based on the existing difference between
people (e.g age, gender, phobias). Nobody manipulated the IV- it just exists.
- Allows comparisons between other types of people
- Often carried out under controlled conditions (sharing strengths as lab
experiments)
- Cannot randomly allocate participants to conditions
- Participants may be aware of being studied
Validity
● Internal validity- refers to how valid the procedure of the experiment is. The
more controlled the study is the higher internal validity it has.
● External validity- refers to how generalizable the results are to the general
public. The more realistic the study is the higher the external validity is.
Summary: Internal validity- how valid procedure of experiment is, External validity- how generalisable
results are to the public. Lab- controlling variables and environment is controlled, Field- IV changed to
everyday setting, Natural- Researcher uses naturally occurring IV (IV not changed), Quasi- IV based on
existing differences between people.
Key points/ Notes/Diagrams:
Main Ideas/
Laboratory experiment- An experiment conducted in a highly controlled environment
Questions: where every variable can be carefully controlled. Researchers manipulate the IV and
record the effects of the DV. Researchers want to record the physiological effects of
What is a lab the participants and stimuli (e.g bright light, loud noise, electric shock).
experiment? - Highly controlled
- Can be easily replicated
What is a field - Confounding variables minimised (higher internal validity)
experiment? - Artificial situation (lack of generalizability and low external validity)
- Participants know that they’re in an experiment (demand characteristics)
What is a natural - Tasks participants are asked to carry out may not represent real life
experiment? experiments (low mundane realism)
What is a Quasi Field experiment- An experiment conducted where the IV is manipulated to a normal
experiment? everyday setting (e.g researchers tested if people were more likely to listen to a
person dressed up like a guard, milkman or normally).
What are the pros - Less artificial compared to lab experiments
and cons of each - Participants are usually unaware that they’re being studied
type of experiment? - Loss of control of confounding variables
- Ethical issues- participants unaware and they can’t give out consent/ lack of
What does internal privacy
and external validity
mean? Natural experiment- The researcher takes advantage of the naturally occurring IV,
therefore the researcher doesn’t manipulate the IV. (e.g the researcher could take
advantage of two different cultures that use different parenting styles and then
measure the differences in the future relationships of kids).
- Allows research where IV can’t be manipulated for ethical reasons
- Enables psychologists to study real problems (increased mundane realism
and ecological validity)
- A naturally occurring event may only happen rarely, reducing opportunities
for research and generalising findings to similar situations
- Cannot demonstrate a casual relationship because the IV is not directly
manipulated
Quasi experiment- Having IV that is based on the existing difference between
people (e.g age, gender, phobias). Nobody manipulated the IV- it just exists.
- Allows comparisons between other types of people
- Often carried out under controlled conditions (sharing strengths as lab
experiments)
- Cannot randomly allocate participants to conditions
- Participants may be aware of being studied
Validity
● Internal validity- refers to how valid the procedure of the experiment is. The
more controlled the study is the higher internal validity it has.
● External validity- refers to how generalizable the results are to the general
public. The more realistic the study is the higher the external validity is.
Summary: Internal validity- how valid procedure of experiment is, External validity- how generalisable
results are to the public. Lab- controlling variables and environment is controlled, Field- IV changed to
everyday setting, Natural- Researcher uses naturally occurring IV (IV not changed), Quasi- IV based on
existing differences between people.
