In this unit you will acquire an understanding of some of the basic tactics used in conducting scientific research. You will learn to define an hypothesis and the relevant variables in meaningful terms, and to select the most appropriate research design for testing the hypothesis. You will learn which among the many statistical procedures might be used to test results and to compare those results with the probability of their occurrence.

In science, data must be collected in an orderly way and presented in a form that makes its meaning and significance clear. A scientist often needs to use statistical techniques in describing data to others and in reaching conclusions about the validity of the hypotheses being tested.

Sophisticated research techniques can only be used by people with training in research

This unit is not a complete course in research methodology, but it will provide you with a general understanding of the considerations involved in scientific inquiry. Scientific inquiry is no more than an orderly approach to defining questions in meaningful terms and to seeking valid answers. In an experimental situation, in which variables are all under close control, one can use very specialized, sophisticated, research and analytical techniques. It is important, therefore, to distinguish between the techniques and the approach. The most sophisticated techniques can be used only in controlled environments, but the orderly/ approach in scientific inquiry is appropriate whenever an idea, or hypothesis, needs to be formulated and tested.

One must be careful to select techniques that are appropriate to the inquiry and the research conditions, but the approach of scientific inquiry is too valuable to be restricted to the laboratory. You should make it a part of your thought processes whenever you seek answers to questions in everyday life.

The logic of scientific inquiry is applicable in the solution of day-to-day problems

After completing this unit, you should be able to describe the essential steps that are taken in scientific inquiry. The unit consists of six modules which will take you, step by step, through the sequence of thought and logic of scientific inquiry, explaining the most important approaches and techniques that scientists use in each step. The basic sequence is described in the following brief summary of the contents of each module.

Module 1 The Tasks of Science--Describes the role of theory in scientific inquiry and the process of generalization from facts that have been observed to overall conclusions about phenomena that have not been observed directly.

Module 2 The Design of Experiments Outlines the basic alternatives from which a researcher selects the approaches and techniques to be used in conducting research. An experiment may be designed in many ways; the objective is to select the design that is most likely to provide valid evidence for or against the hypothesis being tested.


Module 3 Defining, Measuring, and Scaling Presents the principal ways in which a researcher decides what to observe. This includes the identification of the psychological phenomena that are relevant to the hypothesis and the terms in which they will be measured and recorded.

Module 4 Collecting and Organizing Data Describes the techniques for recording and summarizing basic information about the observations made during the research. Many insights into trends and patterns become possible as soon as raw data are organized in an orderly and meaningful way.

Module 5 Descriptive Statistics Explains the use of statistics to describe what actually happened during the research. Before trying to generalize to other situations, one should understand fully the implications of the experimental results.

Module 6 Inferential Statistics Summarizes the principal analytical techniques used in determining the inferences that can be made confidently from the research results. The question here is not "What happened?" but "What could we expect to happen in other situations or with other populations?"

Studying this unit alone will not equip you to carry out a complex research project; you will not be able to do all the things psychologists do. But you will be able to think about problems as a psychologist does.

The authors owe a special debt to Peggy A. Keilman, Ph.D.

Louisiana State University for the
content design of this unit and the
preparation of the first manuscript.



The Tasks of Science

In the past, men have sought to resolve psychological issues through the use of arguments or even force. The Spanish Inquisition combined the authority of God with torture to resolve differences in theory about the way people behave or should behave. Even today, people who believe that prisons do (or do not) rehabilitate prisoners defend their positions with nothing more concrete than quotes from important people who seem to agree with them. Most people are unaware that scientific methods could be used to settle such disputes.

A scientific inquiry approaches a problem in a systematic way

The most commonly accepted definition of science is that it is a systematically organized body of knowledge about the universe. The key word is systematicalLy. Randomly acquired knowledge may be helpful, but the task of a scientist s to organize observations into reliable theories that enable him to comprehend, predict, and control natural phenomena. As you study this module, keep the following questions in mind.


Sciences can be differentiated by their subject matter. Psychology differing from other sciences in that it takes as its subject matter the behavior of man and the lower animals. Like many other sciences, psychology exists in pure, applied, and popular forms. Academic psychologists, who teach in colleges, are most concerned with the pure science of psychology. These psychologists attempt to find answers to such questions as "What is the nature of perception?" or "How does the similarity between a present learning task and some previous experience affect the learning of this task?"

There are three basic approaches to the study of psychological phenomena

Applied psychologists are often employed in industry, or they are in private practice. They may be concerned with designing new instructional approaches or providing treatment for mentally disturbed clients. In any case, they use the knowledge and techniques of the science of psychology to solve specific problems.

Since the study of man is interesting to most people, there has always been a group of people that we might call popular psychologists. In recent years the popularity of psychology has increased considerably, and so has the number of popular psychologists. Novels, movies, stage plays, and articles frequently have psychological themes. These presentations are often superficial, and they tend to concentrate on issues that are popular at the moment, as illustrated by the number of TV shows about crime, sex, and drugs. However, as pointed out by Wilson (1973), popular works in the social sciences can be worthwhile.

... "Popular" is not synonymous with "ignorant" or "ill-informed," although there are people, such as writers for sensational magazines, who have little information and deliberately distort what information they have. However there are others who have been more conscientious. George G. Leonard (1970) is extraordinarily well informed about education. He has studied the subject exhaustively, has visited hundreds of schools, has won many awards for educational writing, and has often served as an educational consultant. But in his book, Education and Ecstasy, he recommended sweeping changes in the educational structure that went far beyond the question of learning effectiveness. They were changes that would alter the basic rote of education in society. Further, in supporting these recommendations, almost all of the evidence he presented was in the form of anecdotesÄinteresting stories about a conversation with a teacher or a student, or a visit to a classroom, and the impressions he had formed during these experiences. In other words, although he is an acknowledged expert in education, his dramatic recommendations here based on evidence that is within the experience of any layman.

The Role of Theory in Science

To a scientist, "theory" is not synonymous" with conjecture"

To a layman, who is exposed most often to popular psychologists, theory often implies someone's unsupported or unfounded notion of how things ought to be done. With only this exposure, one might view theory as a set of ideas is not synonymous that have not been demonstrated to work in practice. But for scientists theory with is the glue that holds scientific observations together;. Theory is a set of principles, forming an organized structure, that is essential to explain the facts obtained through systematic observation.

Facts do not explain themselves Theories provide the framework for scientif c inquiry

One could organize a body of knowledge similar to the way one organizes a catalog; that is, by collecting and listing vast numbers of independent facts. But this would be only a small portion of a scientist's task. For example, if a third grade teacher asked such a ``catalog scientist" what conditions facilitate learning, all the scientist could do would be to hand her his collection of data.


This obviously would not be of much use; she is a teacher, not a psychologist, and would be no better able to interpret and generalize from the reams of data than would the scientist be able to devise a modern math program. To paraphrase an old saying, one general principle is often worth a thousand facts. A true scientist might have told the teacher, ``Children seem to learn more effectively when the behavior conducive to learning is followed immediately by some sort of reward." This is a theory, which might have provided her-with a "tool" that she could use in achieving her objectives as a teacher.

This theory summarizes a vast number of observations. It may be that the theory is not wholly accurate, but at least it provides an explanation of the data in a useful form. As we noted, a scientific theory is a general principle used to explain observed facts. Such theories are often stated in the form of relationships. For example, the scientist's response to the teacher was essentially a statement of a relationship between learning and rewards. In many sciences, such relationships are described in formal terms, using mathematical expressions. Unfortunately there are few theories in psychology which can be stated with such precision. Most of the laws relating to human behavior are empirical statements; they describe the relationship between several events. Statements such as "Frustration leads to aggression," or `'The ease with which items are learned depends on their meaningfulness to the learner" are examples of the present level of precision of psychological theories.

Theories serve three important functions. First, a theory can summarize many observations. The law of gravity, for example, summarizes a considerable number of observations about apples, stones, feathers, and so on, as they fall to the ground. In psychology, the theory of reinforcement is described as the process of strengthening behavior with the use of consequent events. This statement summarizes a number of observations about various reinforcers, such as candy, money, praise, affection, and so on, and the effects of these on behavior

The second function of a theory lies in its value as a predictor. A good theory describes what will happen in certain conditions. For example, when the astronauts ventured into outer space, they found that the prediction of weightlessness, derived from Newton's laws of gravity, was accurate. Psychologists' theories provide fewer instances of events that can be predicted with accuracy, but there are some. For example, we can accurately predict the response of a pigeon who is placed on a "fixed ratio of 10" reinforcement schedule. In general, however, such exact predictions are not usually possible, not because behavior is "unlawful," but because it is impossible to isolate one factor from the enormous number of other factors influencing the behavior of a living organism. Therefore, we often use statistical methods to predict the behavior of groups, as when pollsters predict the outcome of elections.

The third function of a theory is as a guide in making further observations and in conducting research. To take another example from physics, the theory of the nature of the atom led scientists to conduct experiments that resulted in the atomic bomb. There are similar examples in psychology. As we noted in Unit One, the theory of reinforcement led to the development of contingency management and other behavior modification techniques being used today in education and therapy.


What Makes a Good Theory?

It is not uncommon in science for someone to propose a theory that contradicts some commonly accepted one. Scientists recognize that this is inevitable, and even desirable (although such an event may generate many heated arguments). But a nonscientific observer may become quite exasperated and demand to know which theory is true. In a very real sense, no theory is entirely true. That is, no theory explains everything. Usually the only reasonable question one can ask is "Which is the best theory?" That is, "Does one of these theories do a better job than the other of accounting for the facts as we now know them?" It would be ideal if we could answer such questions purely objectively, but scientists have emotions too, and sometimes they persist in holding on to an old theory that has been shown to be less effective than a new one. Ancient astronomers assumed that the earth was the center of the universe. they therefore developed a very elaborate theory in order to explain the apparent motions of the stars. Galileo, many centuries later, advanced the heliocentric theory. He theorized that the sun was the center of our solar system. His theory did a better job of explaining the facts, and eventually became generally accepted, although not without much furor.

The best theory is the one that is the most consistent with all the facts available

If we develop a theory to account for certain phenomena, can we be sure it can be generalized to other seemingly similar phenomena? In psychology, this is a particularly important question. Many theories can be tested only with lower animals, because of ethical or moral restrictions, or because we wish to control for factors that are more easily dealt with in animal experiments. But is what we learn about lower animals applicable to the science of human behavior? This particular point was discussed recently in an article by psychologists Harry Harlow, John Gluck, and Stephen Suomi, reproduced on the following pages.


1. What is the best definition of theory?
a. Someone's unsupported notion of how things should be done.
b. A set of principles obtained in a highly artificial manner that often does not work well in practice.
c. A set of general principles used to explain observed facts.

2. Which is true? a. No theory is completely true. b. All theories fail to explain something. c. Theories are seldom useful for making predictions. d. (none of the above)

3. Match the function of theory with the following examples.

a. Theory permits us to summarize.

b. Theory permits us to predict.

c. Theory acts as a guide for collecting further observations.

(1) Freud developed his theory of personality after treating many emotionally disturbed people as part of his psychiatric-medical practice in Vienna.

(2) From their knowledge of reinforcement schedules, a group of military researchers increased a radar operator's attention by having a computer deliberately introduce false blips on the screen at varying intervals of time.

(3) The formulation of the theory for the teaching machine, by B. F. Skinner, incited investigations of issues such as how active responding affects learning, the effects of immediate knowledge of results, and so on.

(4) The U.S. government would like to help a small Caribbean republic to develop an almost barren coral island into productive farmland. The principal problem is that the citizens of this republic have little experience or interest in farming. A psychologist is called in to design an incentive system that would encourage local citizens to become farmers.

(5), A psychologist, using David Premack's theory that high-probability behaviors could be used as reinforcers, designed a system whereby children were reinforced for reading by being allowed to do such things as yelling, running down the hall, pushing the teacher around in a swivel chair, playing in a bucket of water, and so on.

4. The following question has no right or wrong answer. After reading the article by Harlow, et a/, do you believe that chimpanzees can think?

Now check your answers with those given on page 71. If you are satisfied that you understand each point, go on to the next module. If you are having some difficulty, reread the module.



Unit 13 Table of Contents

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