Module 5 – The Scientific Method and Description (Study Notes)

The Scientific Method

• Psychologists use the scientific method to support their scientific attitude: a self-correcting process using observation and analysis to evaluate ideas.
• Three elements of the scientific attitude (from Module 1): curiosity, skepticism, humility.
• The scientific method combines observation and analysis to test ideas, refine theories, and advance understanding.

Theories

• A theory is an explanation using an integrated set of principles that organizes observations and predicts behaviors or events.
• Example: If we repeatedly observe that a classmate who gets plenty of sleep usually has the right answer, we form a principle that sleep must improve memory.
• How theories advance science:
  • They generate testable predictions (hypotheses).
  • They guide research and interpretation of results.
  • They can be revised or rejected based on evidence.
• Theories help organize observations and provide a framework for understanding.

Hypotheses

• A hypothesis is a testable prediction, often implied by a theory.
• Example: To test a theory of sleep's effects on memory, the hypothesis might be that when sleep deprived, people will remember less from the day before.

Theory vs. Hypothesis

• Theory: uses observations to explain behavior and phenomena.
• Hypothesis: a testable prediction about behavior that can be empirically evaluated.
• Relationship: theories generate hypotheses; hypotheses test and inform theory.

From theory to research

• The cycle: theory → hypothesis → research.
• The results will either support the theory or lead to revision/rejection of the theory.
• Mnemonic: "The rat is always right" – data drive theory adjustment.

Operational Definitions

• Definition: a carefully worded statement of the exact procedures (operations) used in a research study.
• Example: Blindly using an abstract term like "intelligence" is vague; operationally define it as what an intelligence test measures.
  • Variable is quantified as a score on an intelligence test: ext{Intelligence Score} = ext{IQ test result}.
• For a hypothesis, we specify how we will measure each term:
  • Sleep deprived: ext{Sleep deprived} riangleq ext{Normal sleep} - 2 ext{ hours}
  • Remember less: measured by the number of words correctly recalled after a normal night of sleep versus a shortened sleep night; define
    ext{Recall}{ ext{short}} - ext{Recall}{ ext{normal}}
• Why important: replication. If terms are operationally defined, other researchers can replicate the study precisely.

Why operational definitions matter

• Operational definitions allow exact replication of procedures.
• Replication confirms results and strengthens confidence in findings.

TRY IT: Developing hypotheses and operational definitions

• Prompt: What hypotheses would you form for the following theories?
  • Music helps plants grow.
  • Ginger tea helps reduce hyperactivity in teens.
  • Eating junk food causes weight gain.
• For each, draft a hypothesis and then practice operational definitions for the key terms.

TRY IT: Operational definitions in practice

• Plants exposed to music show increased growth. Consider:

  • What type of music?
  • How loud?
  • How long will plants be exposed?
  • What plant species?
  • How will growth be measured?
  • How often will measurements be taken?

• Drinking ginger tea reduces hyperactivity in teens. Consider:

  • How much tea per subject?
  • What are the ingredients?
  • How often will tea be consumed?
  • How will hyperactivity be measured?
  • What age range?
  • Are subjects diagnosed with ADHD?

• Eating junk food causes weight gain. Consider:

  • How do we define junk food?
  • Which brands/products will subjects consume?
  • How much and how often?
  • How will weight gain be measured?
  • What are baseline weight ranges?
  • How active are participants?
  • Gender considerations (men or women)?

How can we test hypotheses and refine theories?

• Descriptive methods
• Correlational methods
• Experimental methods

Descriptive methods: three main approaches

• Case studies
• Naturalistic observation
• Surveys and interviews

What is a case study?

• A descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles.

How do psychologists use case studies to observe and describe behavior?

• Examples include:
  • One individual: Patient H.M.
  • Other individuals: Little Hans, Genie (feral child)
  • One group: University of Tennessee women’s basketball team
  • Prison inmates in a group therapy study

What are the strengths and limitations of the case study method?

• Strengths:
  • Allows examination of rare or unusual behavior.
  • Provides a large amount of qualitative data.
  • Suggests directions for further study.
• Limitations:
  • Atypical cases can be misleading.
  • Results from one study may not generalize to the larger population.
  • Cannot determine cause and effect.

What is naturalistic observation?

• A descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation.

How do psychologists use naturalistic observation to observe and describe behavior?

• Example: watching chimpanzees in the jungle.
• Another example: Mehl and Pennebaker attached voice recorders to 79 college students to listen in on day-to-day conversations.
• Another example: counting positive and negative words in 504 million Twitter messages from 84 countries.

Strengths and limitations of naturalistic observation

• Strengths:
  • Subjects behave "normally" outside of a lab setting.
  • Data collection is unobtrusive (doesn’t disturb the subject).
• Limitations:
  • Independent variable cannot be isolated.
  • Cannot determine cause and effect.
  • Observations by researchers may be subjective.

What is a survey?

• A descriptive technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.

How do psychologists use the survey method to observe and describe behavior?

• Examples:
  • Half of Americans reported more happiness and enjoyment than worry and stress (Gallup, 2010).
  • 1 in 5 people across 22 countries believe alien beings have come to Earth and walk among us (Ipsos, 2010).
  • 68 percent of all humans—about 5 billion people—say religion is important in daily lives (Diener et al., 2011).

What would you answer? (survey-focused quiz items)

• Example question: Which question is best investigated by means of a survey?
  • A) Are people more likely to vote Republican or Democrat in the next election?
  • B) Are violent criminals genetically different from nonviolent criminals?
  • C) Does extra sleep improve memory?
  • D) What is the best study technique for AP exams?
  • E) What role does exercise play in weight loss?
  • Answer: A

Strengths and limitations of the survey method

• Strengths:
  • Quick pulse of beliefs, behaviors, or opinions.
  • Can include many cases.
• Limitations:
  • Response bias
  • Wording effects can skew outcomes
  • Acquiring a random sample is difficult
  • Cannot determine cause and effect

TRY IT: Wording effects in surveys

• Example: Do you support aid to the needy? vs Do you support welfare?
• Finding: More people respond favorably to the first statement than the second.
• Implication: Wording has significant effects on responses.

TRY IT: Sampling bias in surveys

• Scenario: Survey finds 94% of people support federal funding of the space program.
• Questions to ask: Where was the survey conducted? Who was in the sample?

Why is the survey location a possible problem?

• Different locations can yield different results (example locations given: Washington, D.C. at a Star Wars screening; small Iowa town; at a political event).

Why is the survey population a possible problem?

• Different subgroups (e.g., naval aviators, students at a technical college, prison inmates, teenagers) may have different goals or priorities.

What is a representative sample?

• A representative sample has the same distribution of demographic qualities as the population:
  • Example: if the student population is 25% Hispanic, 30% Asian, 35% African American, 10% Caucasian, then the sample should reflect those percentages.
  • If the population is 50% male and 50% female, the sample should include roughly equal numbers of both sexes.

What is a population and a random sample?

• Population: all those in a group being studied, from which samples may be drawn.
• Random sample: a sample that fairly represents a population because each member has an equal chance of inclusion.

TRY IT: Survey planning

• If you wanted to survey high school students about drug use, how would you identify your population and how would you create a random sample?

What would you answer? (survey-focused quiz items)

• Question: Which is most important when conducting survey research?
  • A) Choosing a representative sample.
  • B) Choosing a large sample.
  • C) Choosing a biased sample.
  • D) Choosing a sample that includes every member of the population.
  • E) Choosing a sample whose answers will likely support your hypothesis.
  • Answer: A

4. What would you answer? (methods to study cheating)

• Dr. Cheema is studying the prevalence of cheating on exams at her local high school. Describe one advantage of using each research method:
  • Case study
  • Naturalistic observation
  • Survey

Learning Target 5-1 Review

• Theories are explanations that generate hypotheses – predictions that can be tested and either confirmed, rejected, or revised.
• To enable replication, researchers use precise operational definitions of procedures.
• Replication increases confidence in the results.

Learning Target 5-2 Review

• Description methods (case studies, naturalistic observations, surveys) show what can happen and offer ideas for future research.
• Generalizing about a population requires a representative sample; in a random sample, every person in the entire population being studied has an equal chance of participating.

Connections and implications

• The scientific method underpins ethical, philosophical, and practical considerations in psychology:
  • Openness to scrutiny and replication supports reliability.
  • Operational definitions ensure clarity and comparability across studies.
  • Descriptive methods help generate hypotheses that can be tested with experimental designs.
  • Sampling ethics and representativeness affect the generalizability of findings.