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

1. Laboratory Experiment
2. Field Experiment
3. Natural Experiment
4. 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

1. Clear hypothesis
2. Design contrasting situations that allow to operationalize the variables
3. Design the laboratory and control group
4. Sample the subjects
5. Consider internal and external validity
6. Perform the experiment
7. Debrief the participants
8. Analyse, Interpret and Report 

Advantages

1. You can see behaviour and trigger its cause

Disadvantages

1. Expensive
2. Small samples
3. Laboratory is an artificial setting, may not be generalizable to rest of the “real” world
4. Some behaviours will not act out in laboratory (intimacy, violence, etc.)
5. 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