Experimental Psychology & Research Methods

• Experimental research's importance should be discussed.
• Understand why we rely on scientific methods rather than common sense to explain behavior.
• Discuss the principles of the scientific method and the basic tools of psychological research.
• Understand how "cause and effect" is established by experimentation.

Experiment and Experimental Psychology Defined

• An experiment is when a researcher intervenes in the data generating process by manipulating elements.
• This is also the cleanest way to show a causal relationship between two variables.
• Researchers want control over manipulations to minimize confounding factors.
• Experimental psychology explores and understands behavior through empirical research methods.

Aspects of Modern Science

• Psychologists assume behavior follows a natural order and can be predicted.
• Research psychologists believe behavior has specific causes discoverable through research, known as determinism.

Empirical Data Gathering

• Aristotle advocated systematic observation and classification of naturally occurring events.
• Empirical data should be verifiable or disprovable through investigation.
• Systematic data gathering is preferable to common sense but doesn't guarantee correct conclusions.

General Principles

• Principles applying to all situations are called laws.
• Understanding advances by devising and testing theories, interim explanations.
• Theories unify scientific facts into an organizing scheme to predict new behavior examples.
• Testing predictions stemming from a theory is the cornerstone of psychological science.

Scientific Method

• Good thinking is open to new ideas, even if they contradict prior beliefs.
• Scientists accept uncertainty, reevaluating old information with new facts.
• More supporting evidence increases confidence in a theory.

Publicizing results and Replication

• Scientists exchange information through professional groups and conferences.
• Continuous exchange is vital to the scientific process.
• Replication requires repeating procedures and getting the same results with objective data and good thinking.
• Findings obtainable by only one researcher have limited scientific value.

Psychological Science Objectives

• Description is the first step, involving a systematic and unbiased account of observed behaviors.
• Good descriptions provide knowledge of behaviors.
• Prediction involves knowing when behaviors are expected to occur by identifying linked conditions.
• Explanation understands what causes a behavior and requires an experimental research design.
• Control applies what has been learned about a behavior to effect change or improvement, not always the intent but aims to produce behavioral change.

Research Types

• Applied research solves real-world problems, like helping patients with grief.
• Basic research tests theories or explains psychological phenomena in humans and animals.
• There’s a growing interest in combining both.

Scientific Method Tools

• Observation systematically notes and records events that are observable and consistent.
• Measurement assigns numerical values to objects/events according to conventional rules.

Experimentation

• Testing a hypothesis of behavioral events occurring reliably in specific situations.
• Systematically manipulate aspects of a setting to verify predictions about observable behavior.
• Predictions must be testable with procedures for manipulating the setting, observable outcomes, and measurable outcomes.
• Experimentation must be objective, avoiding biased setups.

Scientific Explanation

• Explanation specifies antecedent conditions of an event or behavior.
• Antecedent conditions are circumstances preceding the event or behavior.
• Identifying all antecedents allows explaining behavior: When XYZ is the set of antecedent conditions, the outcome is a particular behavior.

Treatment Conditions

• Focus on antecedents believed to affect behavior, creates specific sets of antecedent conditions as treatments.
• Compare treatment conditions to test explanations of behaviors scientifically.
• Treatment means treating subjects differently by exposing them to different antecedent conditions and measuring their behavior.
• A psychology experiment applies at least two treatment conditions to subjects.
• Their behaviors are then measured & compared to test treatment effects.
• Requires at least two treatments to compare behavior and observe changes.

Experimentation Procedures

• Psychology experiment procedures are carefully controlled to measure intended outcomes.
• Characteristics of subjects receiving different treatments are controlled via random assignment.
• By assigning treatments using random assignment, avoid systematically different subjects in conditions.
• Ensures people receiving different treatments are equivalent.
• Successful experimentation relies on control where all explanations except those tested are ruled out.
• Control other factors that could produce the effect to explain.
• Greatest control is achieved in a lab, shielding subjects from influencing factors.
• Critics argue lab situations are artificial; thus control is critical to experimentation, sacrificing realism and generalizability for precision.
• Most often achieved by (1) random assignment of subjects to different treatment conditions, (2) presenting a treatment condition identically to all subjects, and (3) keeping constant the environment, procedures, and measuring instruments.

Establishing Cause and Effect

• The greatest value of the psychology experiment is inferring cause and effect.
• If antecedent conditions always lead to a behavior, those conditions cause the behavior.
• Relationship: treatment conditions come before the behavior or the cause precedes the effect.
• Seek temporal relationships and control other factors in experiments to establish cause-and-effect.

Conditions

• Necessary conditions versus sufficient conditions are distinguished.
• Reducing carbohydrates might be sufficient for weight loss but not necessary.

History

• Psychology emerged as an experimental science in the late 1800s.
• Wilhelm Wundt is credited as the first experimental psychologist.
• The birth of psychological science is dated to the opening of his lab in Leipzig, Germany, in 1879.
• Wundt used observation, measurement, and experimentation to study human sensory experience.
• He made gains in measuring sensory phenomena using instruments to calculate how long it took individuals to complete tasks.
• Students worldwide came to Leipzig; one of the first, G. Stanley Hall, opened the first psychology lab in the US in 1883 at Johns Hopkins University.

Pseudoscience

• It was popular in the 1800s (e.g., phrenology).
• The term (pseudo is Greek for "false") characterizes a field that appears scientific without true scientific basis.
• It’s still alive today in astrology etc.
• Contemporary examples include past life regression, reparenting, eye movement desensitization therapy, claiming dramatic and speedy cures without scientific evidence.