Types of experiments

Question 1

Describe and Evaluate Laboratory study

Answer 1

Conducted in controlled, unnatural, laboratory environment
(Sperling 1960, Milgram 1963, Peterson and Peterson 1959 used trigrams, Miller used digit span, Baddeley 1991, dual-task experiments)

Advantages
* High internal validity- Controls EV’s which proves cause and effect of IV and DV
* Can precisely manipulate IV and measure DV due to control, high internal validity.
* Can be easily replicated due to standardised procedure , results in high reliability
Disadvantages
* Lacks Ecological validity due to artificial setting
* Lacks mundane realism which reduces external validity
* Could lead to demand characteristics which could reduce internal validity.

Question 2

Describe and Evaluate Natural experiment

Answer 2

Van Ijzendoorn & Kroonenberg (1988) studied cross-cultural variation in attachment style (DV). They didn’t control the upbringing of the children (IV), this occurred naturally.
Clinical drug treatment experiments
Advantages
* People behave more naturally because they are generally unaware of the experiment.
Demand characteristics are avoided.
* Aspects of behaviour affected by the IV that would be too impractical or unethical to manipulate can be studied

Disadvantages
* Findings can be difficult to interpret.
* Differences between groups may be increased due to individual differences than the effect of the IV.
* Less or no control over extraneous or confounding variables
* Cause and effect is more difficult to establish.
* Ethical issues (e.g. no informed consent)

Question 3

Describe and Evaluate Field Experiment

Answer 3

IV manipulated in natural environment’
Sherif (1960)
Bickman
Hofling

Advantages
* High ecological validity.
* There is control over the IV.
* Reduction of demand characteristics.
Disadvantages
* Can be more time consuming.
* Random allocations to experimental and control groups is extremely difficult.
* Much less control over extraneous variables, reduced internal validity.
* Cause and effect is less certain.
* Ethical issues (e.g. no informed consent, right to withdraw and debriefing).
* There is limited ability for replication.

Question 4

Describe and justify pilot studies

Answer 4

• The term ‘pilot studies’ refers to mini versions of a full-scale study (also called ‘feasibility’ studies), as well as the specific pre-testing of a particular research instrument such as a questionnaire or interview schedule.
• It avoids wasting time and resources which may be spent getting inaccurate results .
• Increases the validity of later research projects if conducted properly as anomalies and problems can be resolved.
• It allows the researcher to determine the most appropriate design and method of data collection to test the hypothesis