Research methods: experiments, interviews, questionnaires, correlation, case study, observation

Introduction to Research Methods

Welcome to one of the most important parts of your Psychology GCSE! In this chapter, we are looking at the tools psychologists use to study human behavior. Think of a psychologist like a builder: just as a builder needs different tools for different jobs (you wouldn't use a hammer to paint a wall!), a psychologist chooses a specific research method depending on what they want to find out.

We will look at the features, strengths, and weaknesses of experiments, interviews, questionnaires, correlations, case studies, and observations. Understanding these will help you answer questions in both Paper 1 and Paper 2.

Note: For details on how to choose participants or write hypotheses, see the "Sampling" and "Variables" chapters in this section.

1. Experiments

Experiments are used when a researcher wants to find out if one thing causes another. They look for a cause-and-effect relationship between an Independent Variable \(IV\) and a Dependent Variable \(DV\).

A. Laboratory Experiments

These take place in a controlled, artificial environment (not always a science lab, but a room where the researcher is in charge).

• Strengths: High levels of objectivity and control over extraneous variables. This makes them easy to repeat to check for reliability.
• Weaknesses: The setting is artificial, so participants might not behave naturally. This means the results might lack validity (they don't reflect real life).

B. Field Experiments

These happen in a real-world setting, like a school or a shopping center. The researcher still changes the \(IV\), but the participants often don't know they are in a study.

• Strengths: Behavior is more natural than in a lab, leading to higher validity.
• Weaknesses: It is much harder to control extraneous variables. There are also ethical issues because participants may not have given informed consent.

C. Natural Experiments

In these studies, the researcher does not change the \(IV\). Instead, they take advantage of a change that happens naturally (e.g., a town getting TV for the first time).

• Strengths: Allows psychologists to study things that would be unethical to trigger on purpose.
• Weaknesses: You cannot randomly assign people to groups, and you have very little control over variables, making it hard to prove cause and effect.

Quick Review: Lab = High control, low realism. Field/Natural = High realism, low control.

2. Questionnaires and Interviews (Self-Report)

These methods involve asking people about their thoughts, feelings, or behaviors.

Questionnaires

A set of written questions. These can include:

• Closed-ended questions: Participants choose from fixed options (e.g., "Yes/No"). These produce quantitative data (numbers).
• Open-ended questions: Participants answer in their own words. These produce qualitative data (detailed descriptions).

Strengths: You can collect a lot of data from many people quickly. They are usually highly reliable because the same questions are used for everyone.

Weaknesses: Participants might give "socially desirable" answers (lying to look good), which lowers validity.

Interviews

• Structured: Set questions asked in a fixed order. (Strong reliability, but less detail).
• Unstructured: More like a conversation; the interviewer follows the participant’s lead. (High detail/validity, but hard to repeat).
• Semi-structured: A mix of both—some set questions, but room to follow up.

Strengths: Unstructured/semi-structured interviews provide rich, qualitative data and allow for subjectivity (understanding the person's unique perspective).

Weaknesses: Interviews can be time-consuming and expensive. The interviewer’s presence might influence how the person answers.

3. Correlations

A correlation looks at the relationship between two variables to see if they change together. For example, is there a link between hours of revision and exam scores?

• Positive Correlation: As one variable goes up, the other goes up.
• Negative Correlation: As one variable goes up, the other goes down.
• Zero Correlation: There is no relationship at all.

Strengths: Good for identifying relationships between variables that we can't easily experiment on. It provides a starting point for further research.

Weaknesses: Correlation does NOT equal causation! Just because two things are linked doesn't mean one caused the other. There might be a "third variable" involved.

4. Case Studies

A case study is an in-depth investigation of a single person or a small group. These are often used for unique individuals, such as someone with a specific type of brain damage.

• Strengths: Provides very rich, detailed qualitative data. It allows us to study rare behaviors that would be impossible to create in a lab.
• Weaknesses: The findings are very specific to that one person, so it is hard to generalise the results to the wider population. They can also be subjective as the researcher may become too involved.

5. Observations

This involves watching and recording behavior. Observations can be naturalistic (watching people in their own environment) or controlled (watching people in a set-up space like a playgroup).

• Strengths: High validity because researchers see what people actually do, rather than what they say they do.
• Weaknesses: They can be unethical if people don't know they are being watched. There is also a risk of observer bias, where the researcher sees what they expect to see.

Key Terms Summary Table

When evaluating these methods, always use these "Big Six" terms from your syllabus:

Validity: Does it measure real-life behavior? (Accuracy)
Reliability: Can the study be repeated and find the same result? (Consistency)
Generalisability: Can the results be applied to the wider population?
Ethics: Was the study morally right? (Consent, protection from harm, etc.)
Objectivity: Is the research free from personal bias and based on facts?
Subjectivity: Is the research based on personal feelings or opinions?

Common Mistake to Avoid: Don't confuse Experiments with Correlations. Experiments change one variable to see the effect on another. Correlations just measure two variables to see if they are linked.

Did you know? Case studies are often used in Topic 4 (The Brain) because we can't ethically damage someone's brain just to see what happens. Instead, we wait for a natural occurrence and study that person in depth!