Psychology Research Methods and the Scientific Method

The Four Basic Goals of Psychology

Psychology is guided by four fundamental objectives that researchers aim to satisfy through systematic investigation:

• Describe: Documenting and observing behaviors and mental processes as they occur.

• Explain: Identifying the underlying causes and reasons why specific behaviors or mental processes happen.

• Predict: Anticipating how a person will behave or how a mental process will manifest in the future based on established patterns.

• Control or Influence: Applying psychological findings to modify, maintain, or improve behavior and mental well-being.

Assumptions and Attitudes of the Scientific Method

The scientific method is defined as a specific set of assumptions, attitudes, and procedures that guide the creation of investigative questions, the generation of evidence, and the drawing of logical conclusions.

Core Assumptions

• Lawfulness of Events: Psychologists assume that behavior and mental processes are lawful, meaning they follow consistent, identifiable patterns.

• Explainability: There is an assumption that behavior and mental processes have specific causes that can be discovered and explained.

Essential Scientific Attitudes

• Open-mindedness: A willingness to consider new ideas and perspectives.

• Critical Evaluation: The rigorous assessment of evidence before accepting it as fact.

• Caution: Exercising care in interpreting results and making claims.

• Ethical Integrity: Adherence to a strict code of ethical principles and professional conduct.

Steps in the Scientific Method

Step 1: Formulate a Hypothesis

• Hypothesis: A tentative statement describing the relationship between two variables. It must be phrased in a way that can be tested empirically.

  • Example: "Exposure to marijuana increases appetite."

• Variables: Specific factors that can change in ways that are observable, measurable, and verifiable.

• Operational Definition: A precise and detailed description of exactly how the variables in a study will be manipulated (in the case of an independent variable) or measured (in the case of a dependent variable).

Step 2: Design the Study and Collect Data

Psychological research is categorized into two major types, each with its own advantages and disadvantages:

• Experimental Method: Used specifically to demonstrate that one variable causes a change in a second variable. It provides evidence of a cause-and-effect relationship.

• Descriptive Method: Research strategies used for observing and describing behavior. These methods identify factors associated with a phenomenon but do not necessarily prove causation.

  • Common Descriptive Methods: Naturalistic Observation, Surveys, Case Studies, and Correlational Studies.

Step 3: Analyze the Data and Draw Conclusions

• Statistics: Mathematical methods employed to summarize raw data and draw logical conclusions.

• Statistical Significance: A mathematical indication signifying that the research results are unlikely to have occurred solely by chance. It suggests a high degree of confidence that the results reflect a real effect.

Step 4: Report findings

• Replication: The process of repeating or duplicating a scientific study. Successful replication increases confidence in the validity of the original findings.

Theories in Psychology

• Theory: A tentative explanation that attempts to integrate and account for the relationships among various findings and observations.

• Theories serve as essential tools for explaining behavior and mental processes. They are dynamic; they evolve and change as new evidence emerges through continued research.

The Experimental Method and Cause-and-Effect

The experimental method is a rigorous investigation used to demonstrate cause-and-effect relationships by purposefully manipulating one factor thought to produce change in another.

Experimental Variables

• Independent Variable (IV): The factor that is purposely manipulated by the experimenter. It is considered the "cause."

  • Example: In a study on marijuana, the IV might be the content of a cigarette: a plain cigarette versus a cigarette containing $5\,mg$ of THC.

• Dependent Variable (DV): The factor that is observed and measured for change. It is thought to be influenced by the IV and represents the "effect."

  • Example: In the marijuana study, the DV might be appetite, measured as the number of grams of ice cream consumed in $1$ hour.

Participant Assignment and Groupings

• Random Assignment: The process of assigning subjects to experimental conditions so that every participant has an equal chance of being placed in any of the groups. This ensures that individual differences are spread evenly across conditions, reducing bias.

• Experimental Group: The group of subjects exposed to all experimental conditions, including the independent variable.

• Control Group: The group of subjects exposed to all experimental conditions except the independent variable. This group serves as a baseline (comparison point) to check for natural or spontaneous changes over time.

• The Researcher's Role: In high-quality experiments, the DV is measured by a trained rater who is "blind" to the experimental condition of each subject to prevent bias.

Variations in Experimental Design

• Placebo Control Group: A control group where subjects receive a fake treatment (the placebo) to check for the Expectancy Effect. This effect occurs when a subject's behavior changes simply because they believe a change should happen.

• Double-Blind Study: A study in which neither the participants nor the researchers interacting with them know which group has been assigned which treatment.

• Single-Blind Study: A study in which the researcher knows the assignment, but the subjects do not.

Limitations of Experimental Research

• Artificiality: Experimental conditions can sometimes be artificial, meaning results may not generalize well to real-world populations or situations.

• Ethical Concerns: Some issues cannot be studied experimentally if they might cause harm to participants.

• Feasibility: It is often impossible to ethically or practically recreate certain conditions for study, such as the effects of the Oklahoma City bombing or the conditions of war.

Descriptive Research Methods in Detail

Naturalistic Observation

• This involves the systematic observation and recording of behaviors as they occur in their natural setting without researcher interference.

• It allows for the study of behaviors that would be unethical to manipulate in a controlled experiment.

• Settings can include restaurants, college campuses, or bars.

Case Studies

• A highly detailed description of a single individual or a specific event.

• Commonly used to investigate rare, unusual, or extreme conditions (e.g., cases involving bestiality).

• Case-Study Research: This occurs when information from several individual case studies is combined to look for broader patterns.

Surveys and Sampling

• Survey: A questionnaire or interview designed to investigate the opinions, behaviors, or characteristics of a large group.

• Formats:

  1. Questionnaire: A paper-and-pencil format (or electronic equivalent) where subjects respond to structured questions about beliefs, attitudes, or experiences.

  2. Interview: Conducted in person, where the interviewer records the responses.

• Sampling Concepts:

  • Sample: A selected segment of the population used to represent the whole.

  • Representative Sample: A sample that closely parallels the larger population on relevant characteristics (e.g., age, gender, socioeconomic status).

  • Random Selection: A process ensuring every member of the larger group has an equal chance of being included in the sample, helping to ensure the sample is representative.

• Survey Weaknesses:

  • Samples may be self-selected or drawn from limited sources (e.g., subscribers to one specific magazine).

  • Responses may be dishonest; participants may misrepresent personal characteristics or behaviors.

Correlational Studies

• Correlational Study: A research strategy that allows for the precise calculation of how strongly two factors are related to one another.

• Correlation Coefficient: A numerical indicator of the strength and direction of the relationship. It always ranges from $-1.00$ to $+1.00$.

  • The Number: Indicates the strength of the relationship (closer to $1.00$ or $-1.00$ is stronger; closer to $0$ is weaker).

  • The Sign (+/-): Indicates the direction of the relationship.

• Positive Correlation: Both factors vary in the same direction (both increase or both decrease together).

• Negative Correlation: The factors vary in opposite directions (as one increases, the other decreases).

• Critical Rule: Correlation does NOT indicate causation.

Ethics in Psychological Research

Psychologists adhere to a strict code of ethics developed by the American Psychological Association (APA) to protect the dignity and welfare of both human and animal subjects.

Key Ethical Provisions

1. Informed Consent and Voluntary Participation: Participants must agree to take part after being informed of the nature of the study.

2. Protection from Harm or Discomfort: Researchers must not expose participants to dangerous conditions that could cause physical or emotional harm.

3. Use of Deception: Must be justified by the study's potential value and only used when non-deceptive alternatives are unavailable.

4. Confidentiality: All records and participant information must remain private.

5. Information and Debriefing: Participants must be given information about the study and be debriefing after participation is complete.

Statistical Perspectives and Interactive Activities

Descriptive Statistics: "Are You Normal?"

Surveys regarding common American habits reveal the following statistical distributions:

• $68\%$ of individuals roll toilet paper over the spool.

• $79\%$ squeeze toothpaste from the top of the tube.

• $7\%$ look behind the shower curtain when using someone else's bathroom.

• $80\%$ eat corn on the cob in circles as opposed to side-to-side.

• $50\%$ eat Oreo cookies whole.

  • $18\%$ twist the halves apart.

  • $15\%$ dunk them.

  • $17\%$ smash them or add them to other desserts.

• $10\%$ have seen a ghost.

• $27\%$ skip ahead in a book to find out what happens at the end.

• $7\%$ have used hair as dental floss.

Sampling Activity: M&M Colors

M&M/Mars, Inc. claims that color distribution in their candy bags is consistent. For Plain M&Ms, the claimed percentages are:

• Brown: $30\%$

• Red and Yellow: $20\%$

• Green, Orange, and Blue: $10\%$

To test this empirically, students can collect raw data from a bag, convert it into percentages, and generate a hypothesis about the true distribution in the population compared to the sample. Groups then collaborate to form a joint hypothesis based on their aggregated data.