From Research Methods in Psychology

[edit] WHAT ARE YOU STUDYING?

THIS SECTION WILL LOOK AT THE RELATIONSHIP BETWEEN PSYCHOLOGICAL THEORY AND PSYCHOLOGICAL RESEARCH. WE WILL USE SOME EXAMPLES OF PSYCHOLOGICAL THEORIES TO LOOK AT THE RELATIONSHIP BETWEEN RESEARCH AND THEORY.

[edit] Introduction

This section also tells you how to evaluate psychological theory and research. Psychology is a science, and psychological research must be carried out using scientific methods. In this section, we will examine what we mean by science and what we mean when we say that some psychological work is not scientific.

The links between theory and research provide a foundation to much research methodology in psychology. These links might not be taught in your course, and if they are taught, might not be examined. If ‘links’ are not taught explicitly, or if the subject is not examined, then you may want to skip this section, but I suggest that you do try to understand this chapter, because it provides a foundation for the rest of this book.

We start with the description of the role of theories in psychology, and then describe how hypotheses are derived from theories. We then consider a little bit of philosophy of science - how theories and hypotheses relate to one another. Finally, we will look at variables, and see how these relate to theory.

[edit] Theories in Psychology

In this section, we will examine what makes a good theory, and then we will consider why theories are important in psychology.

[edit] Why do we need theories?

If there were no theories, then research would consist of disparate findings, which bore no relation to one another. If psychologists did not rely upon theories then psychological research would not be able to move forward – it would not be able to link facts together.

We will look at the two roles for theories: the role as glue which holds seemingly isolated findings together and the role as a way of generating new hypotheses, which can be tested.

[edit] Example: Biological Theory of Extraversion

Consider the finding:

When lemon juice is placed on the tongue, extraverts salivate less than introverts.

Now we might consider this finding surprising (if you ask most people, they might guess that extraverts would salivate more), but, on its own, at least from the perspective of a psychologist, it is not very interesting. To be interesting to a psychologist, we need to have a theory that explains not only this difference, between introverts and extraverts, but other differences as well. Eysenck (1967) proposed that the difference between introverts and extraverts arises out of a difference of a type of arousal in the nervous systems. In other words, the brains of extraverts are less easily aroused than the brains of introverts. Eysenck’s theory explains, and brings together, many of the findings on the differences between introverts and extravert, for example:

• Introverts are more easily conditioned to blink when a buzzer sounds.
• Introverts and extravert differ in their reaction to both sedative drugs and stimulant drugs.
• Introverts are better at vigilance tasks (tasks that involve looking out for something).

Eysenck’s theory tied all these findings together by providing an explanation. This explanation also explained a large number of observed differences between introverts and extroverts. If the brain of an introvert is easily aroused, they will find reading a book is enough to keep them occupied, however the brain of an extravert will not find reading a book to be interesting. Similarly, for music to penetrate the under-aroused brain of the extravert, it might have to be loud; but the introvert, whose brain is more sensitive, may enjoy music that is played softly

The theory also has implications. An extravert will not perform well in a job that requires long periods of concentration looking for a rare signal – their brain would switch off. An extravert would make a poor proof-reader, whose job is to read books or web pages (such as this one) before they are printed or published, to search for mistakes – the job would not be stimulating enough, and their brain would, effectively, switch off.

This theory invites us to make further hypotheses that can be tested, for example that that there is some fairly fundamental biological difference between introverts and extraverts. We can test our further hypotheses by looking for these differences, for instance by using electroencephalograph (EEG) to study the differences in brain activity. Gale (1973) reviewed a number of EEG studies and found notable differences between introverts and extraverts. A second hypothesis is that if the degree of extraversion is related to some biological difference, we should find that it is an inherited trait. and not the result to environmental factors. Loehlin (1992) reviewed a large number of studies looking at the heritability of extraversion, and concluded that there are strong genetic influences on the trait of extraversion.

[edit] Summary

Theories are very important in psychological research. A good theory should do three things, it should explain findings, it should have implications, and it should generate further testable hypotheses.

Theories serve the function of binding together knowledge, and providing a framework upon which more knowledge can be built.