An elementary laboratory course in psychology

Introduction

It has been our aim in preparing this manual to describe the experiments in such a manner that students who have had only an introductory course in psychology may be able to perform them without further assistance. With this in mind we have tried to give full and minute descriptions even to the point of explaining what may seem obvious to many. We have also given exact directions in regard to the recording of results, even to the extent of supplying models for the tables when necessary, for we consider that training in the systematic arrangement of results is one of the purposes of an experimental course.

The selection of the experiments has been conditioned by the following practical and theoretical requirements : —

1 . It should be possible to perform all the experiments in a halfcourse of five hours a week.

2. It should be possible to perform the experiments with very simple and inexpensive instruments. In most instances when complicated instruments have been employed an additional experiment with simple apparatus has been described. Two or three experiments, owing to their importance, have been included which demand special instruments. These experiments have been starred.

3. It is necessary in most institutions that the experiments be performed by the entire class in one room. It is obvious, therefore, that some experiments in audition, vision, etc., had to be omitted.

4. The experiments should not be too difficult for students beginning psychology. In fact it is hoped that the book may prove useful not only for class work, but for private stud^- ' "" who desire an introductory knowledge of experimen* chology.

IV INTRODUCTION

5. The experiments should present the most essential features in method and the important facts of psychology.

6. It should be possible to obtain clean-cut results and they should be capable of treatment by the student,

7. The experiments should not be too fatiguing as would be a complete verification of Weber's Law, nor disagreeable as are many of the taste and smell experiments.

In order to meet these conditions, compromises had to be made, and for one reason or another some experiments have been omitted which appear in standard textbooks. On the other hand, new experiments, arranged to cover what seemed to us important facts, have been included.

Questions have been appended to each experiment. These nave been carefully arranged to direct the student's attention to the main purpose of the experiment, to the reasons for the various stages in the method, to the connection between the results of the various experiments, to the facts and theories, both physiological and psychological, connected with the experiment, and to the practical application of the results. The difficult questions have been starred and may be omitted if deemed advisable.

Most of the experiments are to be performed by the students working in pairs. One student acts as subject, the other as experimenter. A few experiments, entitled " Individual Experiment " are performed by each student upon himself. Some important experiments, however, could not be arranged to be performed by each pair of students separately. These are entitleo " Class Experiment." In these the instructor or one of the students acts as experimenter and the class as a whole acts as subject.

It is advisable to tabulate as far as possible the results of all the members of the class for a comparison of the individual records, and also to obtain averages for large groups. Directions for ' * -^ this have been given in a nimiber of experiments. If the 7ery large, however, this must be omitted, unless the class vided into small sections.

INTRODUCTION V

We must acknowledge our indebtedness to Professor E. B. Titchener's Experimental Psychology. As the influence of this book is felt in every comer of the psychological laboratory of to-day, an attempt to make specific acknowledgments to him would, we fear, involve grave omissions. We have also profited from An Experimental Study of Sensation, by Professors E. B. Holt and R. M. Yerkes. We used this book at Harv^ard for a number of years and have received numerous suggestions from it. One of the experiments on "Attention " was devised by Professor Miinsterberg, and we have to thank him for his permission to use it as well as for his valuable advice. We also wish to thank Professor E. B. Holt for his aid in several important decisions, and Professor W. F. Dearborn for suggestions regarding some of the problems of perception.

Herbert Sidney Langfeld Floyd Henry Allport

Foreword To The Student

At the beginning of the course you are to select a congenial partner with whom to work. It is advisable that this partnership remain unchanged throughout the semester. One member of the pair acts as subject and the other as experimenter. These positions must be reversed in the successive experiments, the subject in one experiment being the experimenter in the next. Some experiments, however, are repeated so that each member shall have the experience both of experimenter and of subject. The work is done at small tables, the subject being seated opposite the experimenter.

It is the aim of experimental psychology, as it is of every other science, to be exact. You are therefore to take the greatest care in the arrangement of the experiment, so that the mind of the subject can be studied under known conditions. The observations must also be most conscientiously made and the results accurately recorded.

You must reali2e the importance of these requirements from the start. Remember that it is an ideal of science that experiments shall be capable of repetition at some future time under the same conditions. If these conditions are not accurately known, there is small possibility of verifying the results, and without such verification the results will have very little if any scientific value.

The experimenter is able to control and describe the outer conditions of the experiment; the subject must control and describe as far as possible his own states of mind. This observation of his mental states is known as * introspection,' and in all the experiments the subject is called on to report upon these states. The records must contain both the so-called ' subjective ' and ' objective ' conditions and results, of the experiment.

viil FOREWORD TO THE STUDENT

Provide yourself with a notebook containing detachable sheets of cross-section paper divided into one half centimeter squares. Write only on one side. It is suggested that the experiments be arranged in the notebook in the following manner : —

EXPERIMENT I

SENSATION

I. Vision

I. The Blind Spot

Date: Subject:

Experimenter:

Materials:

Method :

Record :

Questions:

etc.

Foreword To The Student IX

Place the questions on a separate sheet. The method of the experiment should be described in your own language and with such completeness that any one reading your notebook would know how the experiment had been performed. Any pecuUar conditions of the experiment, such as a headache of the subject, should be noted. The subject will have to obtain the records for his notebook from the experimenter.

Before starting an experiment, always read the entire description including the questions.

In order the better to understand the methods and results, as well as to obtain knowledge of further experiments, the following books are suggested: E. B. Titchener's Experimental Psychology, G. M. Whipple's Manual of Menial and Physical Tests, C. E. Seashore's Elementary Experiments in Psychology, and E. C. Sanford's A Course in Experimental Psychology.

Answer the questions fully, giving them careful thought. You will be well repaid for the time spent upon them by the better insight you will obtain into the purpose and implications of the experim.ent. The following books will aid you in answering the questions: For the physiological facts, C. J. Herrick's An Introduction to Neurology, K. Dunlap's An Outline of Psychobiology, E. A. Schaefer's A Textbook of Physiology, W. H. Howell's Textbook of Physiology ; for the facts and theories of psychology, G. T. Ladd and R. S. Woodworth's Elements of Physiological Psychology, C. S. Myers's A Textbook of Experimental Psychology, E. B. Titchener's A Textbook of Psychology, H. Miinsterberg's Psychology, General and Applied, J. R. Angell's Psychology, J. B. Watson's Psychology from the Standpoint of a Behaviorist, and H. C. Warren's Human Psychology.

Contents

Introduction iii