Psychology: Research Methods, Part 1

Psychologists use the scientific method to study behavior.
Characteristics of the Scientific Method:
- Empiricism: Objective observation of the world.
- Replication: Demonstrating and observing a phenomenon more than once.
- Publication: Making observations available for scrutiny and evaluation.

Psychologists:
- Examine evidence behind claims.
- Are open to new ideas.
- Acknowledge the potential to be fooled and design research to protect against it.

A Non-Psychologist…
- does not consider alternative viewpoints.
- clings to beliefs in spite of contrary evidence.
- says, “Believe me, I am an expert.”
A Psychologist…
- is open to alternative viewpoints.
- will change beliefs if contrary evidence is found.
- says, “Examine the evidence and decide whether it supports my claim.”

Goals:
- Describe behavior.
- Predict behavior.
- Identify causes of behavior.
- Explain behavior $\rightarrow$ control/change behavior
Example:
- Description: 5% of preschoolers exhibit aggressive behavior.
- Prediction: Preschoolers who watch more violent TV shows exhibit more aggressive behavior.

Observational Research: Objectively observe and record behavior.
Correlational Research: Measure two variables and determine if a relationship exists.
Experimental Research: Control or manipulate one variable (independent variable) to determine if it causes changes in another (dependent variable).

Theory (Scientific meaning): A systematic body of ideas that organizes what is known about a topic from past observations and makes predictions about future observations.
- Examples: gravitational theory, Piaget’s theory of cognitive development.
Hypothesis: A prediction about the outcome of research, derived from a theory.
- Supported hypothesis $\rightarrow$ evidence for the theory.
- Unsupported hypothesis $\rightarrow$ evidence against the theory.
- Theories gain acceptance as fact with ample support, or are modified/dropped with little support.

Psychologists publish research in peer-reviewed academic journals.
Peer-review ensures high-quality research.
Process:
- Manuscripts are evaluated by knowledgeable researchers.
- Reviewers provide feedback to the author.
- Author revises manuscript and responds to reviews.

Variable: A quality or characteristic that can take on different values for different observations.
- Examples: height, level of happiness, shoe color, exam color, puzzle difficulty, illumination level, year in school, number of others present.
Measurement: Assigning numbers or labels to observations to represent different amounts or qualities.

Psychological variables are often abstract (e.g., happiness, memory capacity, creativity).
Operational definitions define variables in terms of the operations performed to measure them.
- Examples:
  - Happiness: Self-reported rating on a scale of 0-10 (0 = extremely unhappy, 10 = extremely happy).
  - Memory capacity: Number of words recalled from a list of 50.
  - Creativity: Number of different ways a person thinks of for using a paperclip.