Types of Experiment, Chapter 6, 4

Question 1

What is a laboratory experiment?

Answer 1

An experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables

Question 2

What is a field experiment?

Answer 2

An experiment that takes place in a natural setting within which the researcher manipulates the IV and records the effect on the DV

Question 3

What is a Quasi-experiment?

Answer 3

A study that is almost an experiment but lacks key ingredients. The IV has not been determined by anyone (the researcher or any other person)- the ‘variables’ simply exist, such as being old or young. Strictly speaking, this is not an experiment. DV may be naturally occurring or devised by the experimenter and measured in the field or a lab

Question 4

Where are lab experiments conducted?

Answer 4

In highly controlled environments. This is not always a laboratory it could be a classroom where conditions can be well-controlled

Question 5

What are the strengths of lab experiments?

Answer 5

They have high control over confounding and extraneous variables.

Replication is more possible than in other types of experiment because of the high level of control

Question 6

What does lab experiments having high control over confounding and extraneous variables mean?

Answer 6

This means that the researcher can ensure that any effect on the dependent variable is likely to be the result of manipulation of the independent variable

Thus, we can be more certain about demonstrating a cause and effect (high internal validity)

Question 7

What lab experiments having an increased possibility of replication mean?

Answer 7

This ensures that new extraneous variables are not introduced when repeating an experiment.

Replication is vital to check the results of any study to see whether the finding is valid and not just a one-off

Question 8

What are the limitations of laboratory experiments?

Answer 8

Lab experiments may lack generalisability

The participants are usually aware they are being tested in a lab experiment (though they may not know why) giving rise to unnatural behaviour due to demand characteristics

The tasks participants are asked to carry out in a lab experiment may not represent everyday experience (e.g. recalling unconnected lists of words as part of a memory experiment ( low mundane realism))

Question 9

What does lab experiments maybe lacking generalisability mean?

Answer 9

The lab environment may be rather artificial and not like everyday life. In an unfamiliar context participants may behave in unusual ways so their behaviour can not always be generalised beyond the research setting (low external validity)

Question 10

What are the strengths of field experiments?

Answer 10

They have a higher mundane realism than lab experiments because the environment is more natural. Thus field experiments may produce behaviour that is more valid and authentic. This is especially the case as participants may be unaware they are being studied (high external validity)

Question 11

Why do field experiments have a higher mundane realism than lab experiments?

Answer 11

Because the environment is more natural. Thus field experiments may produce behaviour that is more valid and authentic. This is especially the case as participants may be unaware they are being studied (high external validity)

Question 12

What are the limitations of field experiments?

Answer 12

There is a price to pay for increased realism due to the loss of control of CVs and EVs, this means cause and effect between the IV and the DV in field studies may be much more difficult to establish and precise replication is often not possible

Important ethical issues, if participants are unaware that they’re being studied, they cannot consent to being studied and such research might constitute an invasion of privacy

Question 13

What does increased realism in field experiments mean?

Answer 13

This means cause and effect between the IV and the DV in field studies may be much more difficult to establish and precise replication is often not possible

Question 14

What is a natural experiment?

Answer 14

An experiment where the change in the IV is not brought about by the researcher but would have happened even if the researcher had not been there. The researcher records the effect on a DV they have decided on

Question 15

What are strengths of a natural experiment?

Answer 15

They provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons, such as the studies of institutionalised Romanian orphans (Rutter, et al)

They often have high external validity because they involve the study of real-world issues and problems as they happen, such as the effects of a natural disaster on stress levels

Question 16

What are the limitations of a natural experiment?

Answer 16

A naturally occurring event may only happen very rarely, reducing the opportunities for research.

This may also limit the scope for generalising findings to other similar situations

Another issue: participants may not be randomly allocated to experimental conditions(only applies where there is an independent groups design). This means the researcher might be less sure whether the IV affected the DV. Such research may be conducted in a lab and therefore may lack realism and demand characteristics may be an issue

Question 17

What does natural experiments not randomly allocating participants mean?

Answer 17

This means the researcher might be less sure whether the IV affected the DV. Such research may be conducted in a lab and therefore may lack realism and demand characteristics may be an issue

Question 18

What is an example of the issues faced by natural experiments not randomly allocating participants?

Answer 18

For example, in the study of Romanian orphans, the IV was whether children were adopted early or late. However there were lots of other differences between these groups such as those who were adopted late may also have been less sociable than some of the other children which may have made them less appealing for prospective parents

Question 19

What are the strengths of a quasi-experiment?

Answer 19

They are often carried out under controlled conditions and therefore share some strengths of a lab experiment (e.g. replication)

Question 20

What are the limitations of a quasi-experiment?

Answer 20

Like natural experiments , we cannot randomly allocate participants to conditions and therefore there may be confounding variables

Also like in natural experiments, the IV is not deliberately changed by the researcher and therefore we cannot claim that the IV has caused any observed change