Principles and Methods of Scientific Research in Psychology

Principles of Scientific Research

Scientific research in psychology involves systematic investigation to understand cause-and-effect relationships and other phenomena. Psychologists use research and experiments to answer questions about behavior, cognition, and emotion.

• Examples of research topics:

  • Nature of memory

  • Brain function

  • Emotional expression

• Two main types of research within psychology:

  • Basic research

  • Applied research

Basic and Applied Research Methods

Basic Research

Basic research is conducted to study theoretical questions without trying to solve a specific problem. It focuses on general ideas or concepts.

Applied Research

Applied research utilizes the principles and discoveries of psychology for practical purposes, such as finding solutions to real-world problems. It is typically more focused than basic research.

Five Characteristics of Quality Scientific Research

1. Based on measurements that are objective, valid, and reliable

2. Generalizable

3. Uses techniques that reduce bias

4. Made public

5. Can be replicated

Objectivity vs. Subjectivity

Scientific methodology emphasizes objectivity to ensure that findings are not influenced by personal feelings or opinions.

• Objectivity: Involves the use of objective measurements that are consistent across instruments and observers.

• Subjectivity: Occurs when interpretation is influenced by prior beliefs, expectations, experiences, or mood.

Scientific Measurement: Operational Definition

Operational definitions specify the procedures or operations used to measure or observe a variable. This ensures clarity and replicability in research.

• Variables must be carefully defined.

• There are often multiple possible operational definitions for a single concept.

• Operational definitions help establish the credibility of research.

Example of Operationalizing

• "Depression" can be operationalized in various ways, such as through self-report scales or clinical interviews.

Scientific Measurement: Reliability and Validity

• Reliability: Consistency of measurement.

  • Test-retest reliability: Similar scores over time.

  • Interrater reliability: Different raters produce similar scores.

• Validity: The extent to which a measure assesses what it claims to measure.

Important: A test must be reliable to be valid, but a reliable test can still be invalid.

Examples of Causation Between Two Variables

• When debt stress is associated with health problems, consider:

  • Did debt stress cause health problems?

  • Did health problems lead to debt stress?

  • Could a third variable cause both?

Generalizability of Results

• Generalizability: The extent to which results can be applied outside the laboratory to other contexts.

• Random sampling: Ensures the sample reflects the population.

Sources of Bias in Psychological Research

• Researcher bias: Researchers may unintentionally introduce bias during measurement or data collection.

• Demand characteristics: Participants may alter behavior based on perceived expectations.

• Hawthorne Effect: Behavior changes when participants know they are being observed.

• Social desirability: Participants may respond in ways they believe are favorable to the experimenter.

Techniques That Reduce Bias

• Provide anonymity and confidentiality to volunteers.

• Use blind procedures:

  • Single-blind study: Participants do not know the treatment they receive.

  • Double-blind study: Neither participant nor experimenter knows the treatment assignment.

Five Characteristics of Poor Research

1. Lack of falsifiable hypothesis

2. Anecdotal evidence

3. Biased selection of data

4. Appeal to authority

5. Appeal to common sense

• Falsifiability: A hypothesis must be testable and able to be disproven.

• Anecdotal evidence: Personal stories or observations used as evidence, which are not scientifically reliable.

• Biased data selection: Only presenting data that supports a specific view.

• Appeal to authority: Accepting claims based solely on the source rather than evidence.

• Appeal to common sense: Relying on intuition rather than scientific evidence.

Scientific Research Designs

Research design refers to the set of methods that allow a hypothesis to be tested. The choice of design depends on the research question and hypothesis.

• Quantitative: Statistics-oriented

• Qualitative: Participant interview-oriented

• Mixed methods: Combination of quantitative and qualitative

Types of Research

• Descriptive research: Qualitative research, case study, naturalistic observation, self-reporting

• Correlational research

• Experimental research: The experimental method

• Quasi-experimental research

• Surveys

• Biological research

Ethics and Research

Ethical guidelines are essential in psychological research to protect participants and ensure integrity.

• Respect for human dignity

• Respect for free and informed consent

• Respect for vulnerable persons

• Respect for privacy and confidentiality

• Respect for justice and inclusiveness

• Balancing harms and benefits

• Minimizing harm and maximizing benefits

Research in Canada is overseen by The Canadian Tri-Council Research Ethics Code, which provides specific guidelines for ethical conduct.

Descriptive Statistics

Descriptive statistics summarize and organize data. Key terms and definitions are essential for understanding research findings.

• Frequency: The number of times a value occurs.

• Normal and skewed distribution: Patterns of data spread.

• Central tendency:

  • Mean, median, mode (in both normal and skewed distributions)

• Variability:

  • Standard deviation (measure of data spread)

• Hypothesis testing: Statistical method to determine if results are significant.

Table: Comparison of Good vs. Poor Research Characteristics

Good Research	Poor Research
Objective, valid, reliable measurements	Lack of falsifiable hypothesis
Generalizable	Anecdotal evidence
Reduces bias	Biased selection of data
Made public and replicable	Appeal to authority or common sense

Key Equations

• Mean: $\text{Mean} = \frac{\sum x}{N}$

• Standard Deviation: $s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{N-1}}$

Additional info:

• Ethical research also includes debriefing participants and ensuring voluntary participation.

• Descriptive statistics are foundational for understanding more advanced inferential statistics.