4a Methods of Quantitative Psychology

Week: 03/06

Learning Objectives

The last weeks of this course were very philosophical and looked rather general at science. To apply this knowledge to the question of whether psychology is a science, it is essential to understand empirical psychological research and the methods employed in quantitative psychology.

To examine something unobservable (the psyche), modern psychology employs various methods to measure or quantify experiences, emotions, and cognition. But how do these methods work? What are the foundations of these measurements? What types of research designs exist? What are the phases of a research project in psychology?

As an example, we will focus on one of the most popular methods in cognitive psychology: reaction times, also known as chronometric methods.

Required Reading
  • Barker, Pistrang, & Elliott (2015)
    • Chapter 4: Foundations of Quantitative Measurement\(^\textbf{*}\) (only pages 50–57)
    • Chapter 8: Foundations of Design\(^\textbf{**}\)
  • Lindemann & Fischer (2023), Chapter 3: Chronometric Methods\(^\textbf{**}\) (only pages 37–41)

\(^\textbf{*}\) This chapter is to a large extend merely a repetition of the basic ideas of positivism.
\(^\textbf{**}\) The second chapter explains research designs in clinical psychology; the last chapter discusses chronometric methods in the context of “embodied cognition”, which is a disciple of psychology that studies the role of the body on cognitive processes. Note, the two psychological disciples are just examples for us. Everything that is explain in theses chapters counts for any psychological disciple.

Tutorial Meeting

Question 1

What does the term “operatizonalisation” mean? What are difficulties/problem of operatizonalisation?

Question 2

The golden rule of research design is: “Correlation does not equal causation!”

What does that mean? Why is that?

Question 3

What are pre-conditions for causality?

Question 4

What is the difference between descriptive, correlational and experimental designs? When do you use what?

What are the problems of correlational designs?

Question 5

What kinds of experimental designs can we distinguish? Explain the differences.

Question 6

What are criteria exist to judge the quality of an experimental study? Which methods do you know to ensure this quality of an experiment? Explain and generate some examples.

Question 7

Why do we randomize and what are the advantages of randomization?

Question 8

How can we test whether the cognitive processes that are involved in two different tasks are independent? Which law do we need to assume for this (and actually for any kind of reaction time study)?

Question 9

Assume that we want to examine if two process are parallel. How can we do this with chronometric methods?

Study Checklist

  • Operatizonalisation
  • Advantages of quantitative methods
  • Causation
    • General conditions for causality
    • Possible causal relationships
  • Nonexperimental designs
    • Descriptive and correlational designs
  • Experimental designs
    • Four types of validity
    • Threats to validity
    • Nonrandomized designs
    • Randomized designs
    • Types of comparison groups
  • Chronometric methods
    • Hick-Hyman law
    • Donders’ method of subtraction
    • Additive factors logic