5.2 How to Think Straight About Psychology

1. What Is Psychology?

Psychology is a science.

1.1. Characteristics of Science

Science has three characteristics.

1.1.1. Systematic Empiricism

Empiricism: scientists rely on observation to understand the world.

Systematic: observation is structured, meaning it is theory-driven.

1.1.2. Publicly Verifiable Knowledge

Replicability: science must be public so that others can repeat and verify it.

Peer review: every paper submitted to an academic journal needs to be reviewed by several scientists.

1.1.3. Testing Solvable Problems

Science deals with solvable problems. A solvable problem means a testable theory; testable means falsifiable. Falsifiable means that a scientific theory tells us what will happen and what will not happen. If those excluded things happen, then the theory has a problem and needs to be revised.

One of the main methods for achieving falsifiability is operational definition.

1.1.3.1. Operational Definition

An operational definition describes a concept in terms of observable operations.

1.2. Evidence for Scientific Theories

1.2.1. Case Studies

A case study is an in-depth investigation of one individual or a very small number of individuals.

Case studies can provide directions during the early stages of research, but they are no longer useful in the later stages of research.

1.2.2. Testimonials

Testimonials have no value because they may reflect a placebo effect. The placebo effect means that regardless of whether a treatment actually contains an effective therapeutic component, people tend to report that the treatment helped them.

Why do so many people still believe testimonials? Because of the vividness effect: people place too much weight on evidence that is more vivid and therefore easier to retrieve from memory.

1.3. Scientific Experiments

1.3.1. Correlational Research

Correlation does not imply causation. It means that two variables are merely correlated, and this does not guarantee that a change in one variable causes a change in the other.

The reasons include third variables and directionality.

A third variable means that a correlation between two variables does not imply that they have a direct causal relationship; both may instead be related to another unmeasured variable.

Directionality means that when two variables are correlated, A may cause B, or B may cause A.

1.3.2. Scientific Experiments

Use experimental control and random assignment to keep other variables unchanged, manipulate the independent variable, and observe whether it affects the hypothesized dependent variable.

Note that there may be multiple independent variables.

1.4. Scientific Progress

1.4.1. Breakthrough Model

A sudden breakthrough, such as relativity.

1.4.2. Gradual Integration Model

Progress happens step by step; this is the normal pattern.

1.4.2.1. Connectivity Principle

A new scientific theory must not only explain new facts but also remain compatible with old facts before it can be considered genuine theoretical progress.

1.4.2.2. Convergence Principle

If experiment one supports conclusions A and B, and experiment two supports conclusions B and C, then conclusion B may be correct.

1.5. Scientific Conclusions

Some conclusions are probabilistic: they hold in most cases but do not apply in every case.

2. References

How to Think Straight About Psychology: Seeing Through the World with Critical Thinking - Praywu - CNBlogs