1. Psychology Is Alive and Well (and Doing Fine Among the Sciences)

The Freud Problem

The Diversity of Modern Psychology

 Implications of Diversity

Unity in Science

What, Then, Is Science?

Systematic Empiricism

 Publicly Verifiable Knowledge: Replication and Peer Review

 Empirically Solvable Problems: Scientists’ Search for Testable Theories

Psychology and Folk Wisdom: The Problem with “Common Sense”

Psychology as a Young Science

Summary

2. Falsifiability: How to Foil Little Green Men in the Head

Theories and the Falsifiability Criterion

 The Theory of Knocking Rhythms

 Freud and Falsifiability

 The Little Green Men

 Not All Confirmations Are Equal

 Falsifiability and Folk Wisdom

 The Freedom to Admit a Mistake

 Thoughts Are Cheap

Errors in Science: Getting Closer to the Truth

Summary

 3. Operationism and Essentialism: “But, Doctor, What Does It Really Mean?”

Why Scientists Are Not Essentialists

 Essentialists Like to Argue About the Meaning of Words

 Operationists Link Concepts to Observable Events

 Reliability and Validity

 Direct and Indirect Operational Definitions

 Scientific Concepts Evolve

Operational Definitions in Psychology

 Operationism as a Humanizing Force

 Essentialist Questions and the Misunderstanding of Psychology

 Operationism and the Phrasing of Psychological Questions

Summary

4. Testimonials and Case Study Evidence: Placebo Effects and the Amazing Randi

The Place of the Case Study

Why Testimonials Are Worthless: Placebo Effects

The “Vividness” Problem

 The Overwhelming Impact of the Single Case

 The Amazing Randi: Fighting Fire with Fire

Testimonials Open the Door to Pseudoscience

Summary

5. Correlation and Causation: Birth Control by the Toaster Method

The Third-Variable Problem: Goldberger and Pellagra

 Why Goldberger’s Evidence Was Better

The Directionality Problem

Selection Bias

Summary

6. Getting Things Under Control: The Case of Clever Hans

Snow and Cholera

Comparison, Control, and Manipulation

 Random Assignment in Conjunction with Manipulation Defines the True Experiment

 The Importance of Control Groups

 The Case of Clever Hans, the Wonder Horse

 Clever Hans in the 1990s

 Prying Variables Apart: Special Conditions

 Intuitive Physics

 Intuitive Psychology

Summary

7. “But It’s Not Real Life!”: The “Artificiality” Criticism and Psychology

Why Natural Isn’t Always Necessary

 The “Random Sample” Confusion

 The Random Assignment Versus Random Sample Distinction

 Theory-Driven Research Versus Direct Applications

Applications of Psychological Theory

 The “College Sophomore” Problem

 The Real-Life and College Sophomore Problems in Perspective

Summary

8. Avoiding the Einstein Syndrome: The Importance of Converging Evidence

The Connectivity Principle

 A Consumer’s Rule: Beware of Violations of Connectivity

 The “Great-Leap” Model Versus the Gradual-Synthesis Model

Converging Evidence: Progress Despite Flaws

 Converging Evidence in Psychology

Scientific Conse