Designing Research » Field Experiments

What you'll learn this session

Study time: 30 minutes

What field experiments are and how they differ from other research methods
The key characteristics and procedures of field experiments
Strengths and limitations of using field experiments
How to design a valid field experiment
Real-world examples of field experiments in psychology
Ethical considerations when conducting field experiments

Introduction to Field Experiments

Field experiments are a type of research method where researchers test their hypotheses in real-world settings rather than in a controlled laboratory environment. They allow psychologists to study how people behave naturally while still maintaining some experimental control.

Key Definitions:

Field Experiment: An experiment conducted in a natural, real-life setting where the researcher manipulates an independent variable but has less control over extraneous variables.
Independent Variable (IV): The variable that is deliberately manipulated by the researcher.
Dependent Variable (DV): The variable that is measured to see if the IV has had an effect.
Ecological Validity: The extent to which findings can be generalised to real-life settings.

🏠 Natural Settings

Field experiments take place in everyday environments such as schools, workplaces, or public spaces. This means participants behave more naturally as they're in familiar surroundings and often don't know they're being studied.

🔬 Experimental Control

While field experiments happen in natural settings, researchers still manipulate variables and measure outcomes. However, they have less control over external factors that might influence results compared to lab experiments.

Key Features of Field Experiments

Field experiments combine elements of both experimental and observational research methods. Here's what makes them unique:

💡 Manipulation

The researcher changes something (IV) to see what effect it has on behaviour (DV), just like in a lab experiment.

🌍 Natural Setting

Takes place in the real world rather than an artificial lab environment, making behaviour more realistic.

🤔 Participant Awareness

Participants often don't know they're part of an experiment, reducing demand characteristics.

Designing a Field Experiment

When designing a field experiment, psychologists need to follow these key steps:

Identify a research question that can be tested in a natural setting
Choose an appropriate setting where the behaviour naturally occurs
Decide how to manipulate the IV in a way that's practical in that setting
Determine how to measure the DV accurately without disrupting natural behaviour
Control extraneous variables as much as possible
Consider ethical implications of conducting research in public settings

Case Study Focus: Piliavin's Subway Study

Piliavin et al. (1969) conducted a famous field experiment on the New York subway to investigate helping behaviour. They staged scenarios where an actor would collapse on the train. They manipulated whether the victim appeared drunk or ill and whether they were carrying a cane (suggesting disability) or not. Researchers observed how quickly passengers offered help and how many people helped. This study showed that people were more likely to help the 'ill' victim than the 'drunk' victim, demonstrating how field experiments can reveal real-world social behaviours.

Strengths and Limitations

👍 Strengths

High ecological validity - findings can be applied to real-life situations
Natural behaviour - participants act more naturally than in artificial lab settings
Reduced demand characteristics - participants often don't know they're being studied
Studies real-world problems - can investigate issues that matter in everyday life
Can study behaviours that would be unethical to create in a lab

👎 Limitations

Less control over extraneous variables that might affect results
Difficult to replicate as conditions vary in natural settings
Ethical concerns about lack of informed consent
Practical difficulties in setting up and measuring in public places
Observer bias can affect how behaviours are recorded

Ethical Considerations

Field experiments raise specific ethical issues that researchers must address:

Informed consent: Participants often don't know they're being studied, which raises consent issues
Deception: Many field experiments involve some level of deception
Right to withdraw: Participants can't withdraw if they don't know they're participating
Privacy: Observing people in public places may invade privacy
Debriefing: It can be difficult to debrief all participants after the study

Researchers must weigh these ethical concerns against the potential benefits of the research. The British Psychological Society provides guidelines that researchers should follow, including minimising harm and protecting participants' dignity.

Famous Field Experiments

💰 Litter and Theft

Cialdini's Littering Study (1990)
Tested how people's littering behaviour was influenced by the environment. Found people were more likely to litter in already littered environments, demonstrating social norms in action.

🎭 Prosocial Behaviour

Batson's Empathy-Altruism Studies
Investigated whether people help others out of genuine concern or self-interest by manipulating empathy levels in real-world helping situations.

💬 Conformity

Milgram's Lost Letter Technique
Dropped stamped, addressed envelopes in public places to see if people would post them, testing helpfulness towards different groups based on the addressee.

Comparing Field Experiments to Other Methods

Research Method	Setting	Control	Ecological Validity
Laboratory Experiment	Artificial environment	High control	Low ecological validity
Field Experiment	Natural environment	Moderate control	High ecological validity
Natural Experiment	Natural environment	No control (observes natural IV)	Very high ecological validity
Observational Study	Natural environment	No manipulation of variables	Very high ecological validity

Applying Field Experiments to Real Life

Field experiments have practical applications in many areas:

Education: Testing different teaching methods in actual classrooms
Health psychology: Investigating how to encourage healthy behaviours in communities
Environmental psychology: Studying how to reduce littering or encourage recycling
Consumer psychology: Testing how store layouts affect purchasing behaviour
Social psychology: Understanding helping behaviour or prejudice in real-world contexts

Exam Tip 📝

When discussing field experiments in your exam:

Always highlight both strengths AND limitations
Use specific examples to support your points
Discuss ethical issues, particularly around informed consent
Compare to other research methods where relevant
Link to ecological validity and real-world applications

Summary

Field experiments offer a valuable middle ground between the control of laboratory experiments and the realism of observational studies. They allow researchers to manipulate variables while studying behaviour in natural settings, leading to findings with high ecological validity. However, they come with challenges including reduced control, ethical concerns about consent and practical difficulties in implementation.

When evaluating field experiments, remember to consider both their scientific value in understanding real-world behaviour and the ethical implications of conducting research in public settings without full informed consent.

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