, Chapter 1
Chapter 1
Experimental Psychology and the Scientific Method
Chapter Overview
Researchers obtain knowledge about psychological processes by using scientific
methodology. The alternative, commonsense psychology, utilizes nonscientific sources
of data and inference, and is subject to many kinds of errors. Modern science avoids the
errors inherent in commonsense psychology by assuming a natural order (the scientific
mentality). Scientists gather observable data, develop laws or theories to organize and
explain our findings, use good thinking (objective, organized, rational, and parsimonious
reasoning), challenge findings through attempts to falsify–not verify–new hypotheses
(self-correction), publicize results, and repeat experimental procedures to confirm
previous findings (replication). Psychologists revise explanations and theories when
required by the weight of evidence.
The four major objectives of psychological research include description, prediction,
explanation, and control. Diverse psychological research methods are used in both
applied and basic research. The tools of psychological science are observation,
measurement, and experimentation. Researchers manipulate sets of antecedents called
treatments in a psychology experiment. The minimum requirements for an experiment
are that we must have procedures for manipulating the antecedents and the predicted
outcome must be observable. A psychology experiment is a controlled procedure in
which we apply at least two different treatment conditions to subjects and then measure
and compare subject behaviors to test an experimental hypothesis. Scientists use
experiments to infer a cause and effect relationship between treatment conditions and
subjects’ behavior.
When psychology joined the discipline of mental philosophy in the 1800s, it
contended against the popular pseudosciences of phrenology, physiognomy,
spiritualism, and mesmerism. Contemporary psychology deals with their modern
counterparts, like eye movement desensitization therapy. All of these therapies share
the appearance of being scientific, but they lack a scientific basis and have not been
confirmed using the scientific method.
Psychologists begin the experimental process by reviewing the research literature
to generate hypotheses about behavior, which provides the basis for the Introduction
section of a psychological report. We design a procedure to systematically test that
hypothesis, which is described in the Method section. We statistically analyze our
experimental data and report whether or not they support the hypothesis in the Results
section. Finally, we evaluate the meaning of our findings in the context of previous
research and re-evaluate our procedures and hypothesis in the Discussion section
1
, Chapter 1
Chapter Outline
The Need for Scientific Methodology
Nonscientific Sources of Data
Nonscientific Inference
The Characteristics of Modern Science
The Scientific Mentality
Gathering Empirical Data
Seeking General Principles
Good Thinking
Self-Correction
Publicizing Results
Replication
The Objectives of Psychological Science
The Tools of Psychological Science
Observation
Measurement
Experimentation
Scientific Explanation in Psychological Science
Identifying Antecedent Conditions
Comparing Treatment Conditions
The Psychology Experiment
Establishing Cause and Effect
From Pseudoscience to Psychological Science
The Organization of the Text
Summary
Key Terms
Review and Study Questions
Critical Thinking Exercise
Online Resources
Key Terms
Antecedent conditions Observation
Applied research Parsimony
Basic research Pseudoscience
Cause and effect relationship Psychology experiment
Commonsense psychology Replication
Data Science
Empirical data Scientific method
Experimentation Subject
2
, Chapter 1
Good thinking Testable
Laws Theory
Measurement Treatment
Methodology
3
Chapter 1
Experimental Psychology and the Scientific Method
Chapter Overview
Researchers obtain knowledge about psychological processes by using scientific
methodology. The alternative, commonsense psychology, utilizes nonscientific sources
of data and inference, and is subject to many kinds of errors. Modern science avoids the
errors inherent in commonsense psychology by assuming a natural order (the scientific
mentality). Scientists gather observable data, develop laws or theories to organize and
explain our findings, use good thinking (objective, organized, rational, and parsimonious
reasoning), challenge findings through attempts to falsify–not verify–new hypotheses
(self-correction), publicize results, and repeat experimental procedures to confirm
previous findings (replication). Psychologists revise explanations and theories when
required by the weight of evidence.
The four major objectives of psychological research include description, prediction,
explanation, and control. Diverse psychological research methods are used in both
applied and basic research. The tools of psychological science are observation,
measurement, and experimentation. Researchers manipulate sets of antecedents called
treatments in a psychology experiment. The minimum requirements for an experiment
are that we must have procedures for manipulating the antecedents and the predicted
outcome must be observable. A psychology experiment is a controlled procedure in
which we apply at least two different treatment conditions to subjects and then measure
and compare subject behaviors to test an experimental hypothesis. Scientists use
experiments to infer a cause and effect relationship between treatment conditions and
subjects’ behavior.
When psychology joined the discipline of mental philosophy in the 1800s, it
contended against the popular pseudosciences of phrenology, physiognomy,
spiritualism, and mesmerism. Contemporary psychology deals with their modern
counterparts, like eye movement desensitization therapy. All of these therapies share
the appearance of being scientific, but they lack a scientific basis and have not been
confirmed using the scientific method.
Psychologists begin the experimental process by reviewing the research literature
to generate hypotheses about behavior, which provides the basis for the Introduction
section of a psychological report. We design a procedure to systematically test that
hypothesis, which is described in the Method section. We statistically analyze our
experimental data and report whether or not they support the hypothesis in the Results
section. Finally, we evaluate the meaning of our findings in the context of previous
research and re-evaluate our procedures and hypothesis in the Discussion section
1
, Chapter 1
Chapter Outline
The Need for Scientific Methodology
Nonscientific Sources of Data
Nonscientific Inference
The Characteristics of Modern Science
The Scientific Mentality
Gathering Empirical Data
Seeking General Principles
Good Thinking
Self-Correction
Publicizing Results
Replication
The Objectives of Psychological Science
The Tools of Psychological Science
Observation
Measurement
Experimentation
Scientific Explanation in Psychological Science
Identifying Antecedent Conditions
Comparing Treatment Conditions
The Psychology Experiment
Establishing Cause and Effect
From Pseudoscience to Psychological Science
The Organization of the Text
Summary
Key Terms
Review and Study Questions
Critical Thinking Exercise
Online Resources
Key Terms
Antecedent conditions Observation
Applied research Parsimony
Basic research Pseudoscience
Cause and effect relationship Psychology experiment
Commonsense psychology Replication
Data Science
Empirical data Scientific method
Experimentation Subject
2
, Chapter 1
Good thinking Testable
Laws Theory
Measurement Treatment
Methodology
3
