4 – Experiment
Why Should I Care?
Controlling the social environment to conduct science is prone to ethical issues. But doing it right produces great science.
(First Steps Ch. 6)
Definitions
Experiment: A study where techniques are used to isolate, control, and manipulate the major variables in a hypothesis.
Laboratory: An artificial environment where a scientist can control stimuli (independent variables) to observe the cause-and-effect relationship.
Pilot-project: A small scale field experiment that helps an organization test a new idea, program, policy or product.
Usefulness
The key phrase to describe an experiment is: “Similar people in different situations.”
The similarity of the people is achieved by random sample. The different situations are created by the scientist.
Objects of Measurement
|
Type of Object |
Yes |
No |
Maybe |
Example |
|
Personal Characteristic |
X |
|
|
Height, Gender |
|
Socio-Demographic Characteristic |
X |
|
|
Religion, Race, Gender, Income, Language |
|
Opinion |
|
|
X |
Political stripes |
|
Motivations |
|
X |
|
Hope, Greed |
|
Ideology |
|
|
X |
Racist, Right-wing, Left-wing, nationalistic |
|
Biases / Prejudice |
X |
|
|
I trust blue-eyed people than anyone else. |
|
Preferences |
X |
|
|
Price theory (what people pay for, for real) |
|
Personal History / Background |
|
X |
|
Immigration |
|
Family Dynamics |
X |
|
|
Child violence |
|
Cultural History |
|
X |
|
Military History, Political History, Class |
|
Perception / Self-Perception |
|
X |
|
I believe I am wiser than you. |
|
Aptitude /Ability |
X |
|
|
Jumping high, punching, verbal harassment |
|
Behaviour |
X |
|
|
Violence, Kindness |
|
Level of Knowledge |
|
X |
Test |
Sampling
Any size of population, often decided by socio-demographic traits (gender, age, social group).
Samples are usually non-random and small. A size of 30 is the “magic-number”.
Types of Experiments
- Laboratory Experiment
- Field Experiment
- Natural Experiment
- Internet-Based Experiment
Instruments
Questionnaire and Interview: for pre-test, and post-test measurements
Laboratory: to control stimulus and isolate the effect of different independent variables.
Recordings: Notes and audio-video to record behaviour in the field experiment.
Scientific Power
Descriptive: If there is no laboratory, this is the highest level of scientific power possible. You can associate but you cannot reduce.
Explanatory: The whole point of setting up a laboratory is to isolate variables. You can reduce.
See p. 132-134 for discussion of causation
Steps
p.134-135
- Clear hypothesis
- Design contrasting situations that allow to operationalize the variables
- Design the laboratory and control group
- Sample the subjects
- Consider internal and external validity
- Perform the experiment
- Debrief the participants
- Analyse, Interpret and Report
Advantages
- You can see behaviour and trigger its cause
Disadvantages
- Expensive
- Small samples
- Laboratory is an artificial setting, may not be generalizable to rest of the “real” world
- Some behaviours will not act out in laboratory (intimacy, violence, etc.)
- Some topics are not ethical/possible to study (tax effects, economics)
Reporting
Revue québécoise de psychologie. Département de psychologie de l’Université du Québec à Trois-Rivières.
Canadian Journal of Experimental Psychology, Canadian Psychological Association
European Journal of Social Psychology, European Association of Social Psychology
Journal of Experimental Psychology, American Psychology Association
Tables & Graphs
Descriptive Text
Synthesis Tables
Preferred Disciplines
Psychology, Sociology
Other Non-scientific Disciplines
Applications in Biology, Medicine, Chemistry, Pharmaceuticals, Engineering
Not useful for
Historians, Economists, Political Scientists, Geographers, Anthropologists
This being said, the experiment is a method used by a minority of social scientists in other fields such as economists, and anthropologists.
Think Piece
Write a Research Topic, Hypothesis and Design, for your project, as it could apply to an experimental research method.
Why is it so important to debrief participants?
You may have lied to the participant
It shows respect, you are letting them in on the secret…
The participant may have acted immorally because of the setting
The participant may need to let some steam out, emotional reaction
The participant may be scarred unless you treat them appropriately
The participant may have acted differently if he were not in an experiment; he might say so during the debriefing.
A post-hoc interview may discover lots of stuff to help design the next experiment
More reasons, see textbook