PSY402 Official Handouts

LESSON 01

HISTORICAL ROOTS OF EXPERIMENTAL PSYCHOLOGY

Before formal psychology was introduced, philosophers performed studies that lead to the beginning contributions of psychology. They investigated the basic psychological processes. In 350 B.C., Aristotle and Plato wrote interesting ideas about memory, perception, etc. However, in 1880, there were no professors in psychology, no undergraduate programs in psychology, and very few Ph.D.s in the world working in the field that we today call psychology. According to the received view (Boring, 1950), scientific psychology began in Germany as a physiological psychology born of a marriage between the philosophy of mind, on the one hand, and the experimental phenomenology that arose within sensory physiology on the other. Philosophical psychology, concerned with the epistemological problem of the nature of knowing mind in relationship to the world as known, contributed fundamental questions and explanatory constructs; sensory physiology and to a certain extent physics contributed experimental methods and a growing body of phenomenological facts.

Kant’s point of view

Until the middle of the 19th century, psychology was widely regarded as a branch of philosophy. Immanuel Kant (1724-1804), for instance, famously declared in his Metaphysical Foundations of Natural Science (1786) that a scientific psychology "properly speaking" (a phrase in which much is buried) is an impossibility. He then proceeded to produce what looks to modern eyes very much like an empirical (if not "properly" scientific)

Table of Contents

Page no. Lesson 1

Historical roots of experimental psychology

Lesson 2

Lesson 3

Hearing and the other senses

Lesson 4

Perception

Lesson 5

Psychophysics

Lesson 6

Learning

Lesson 7

Classical conditioning

Lesson 8

Operant conditioning

Lesson 9

Memory I

Lesson 10

Memory II

Lesson 11

Memory III

Lesson 12

Forgetting

Lesson 13

Reasoning and problem solving

Lesson 14

Thinking

Lesson 15

Experimental research

psychology in his Anthropology Kant, who denied the possibility that psychology could become an empirical science on two grounds. First, since psychological processes vary in only one dimension, time, they could not be described mathematically. Second, since psychological processes are internal and subjective, Kant also asserted that they could not be laid open to measurement.

Emergence of experimental psychology

Ibn al-Haytham

Born in Basra in 965, Abu Ali al-Hasan ibn al-Hasan ibn al-Haytham was the first person to test hypotheses with verifiable experiments, developing the modern scientific method more than two hundred years before European scholars learned of it—by reading his books. According to the majority of the historians al-Haytham was the pioneer of the modern scientific method. With his book he changed the meaning of the term optics and established experiments as the norm of proof in the field. His investigations are based not on abstract theories, but on experimental evidences and his experiments were systematic and repeatable. Roshdi Rashed wrote the following on Ibn al-Haytham: " His work on optics, which includes a theory of vision and a theory of light, is considered by many to be his most important contribution, setting the scene for developments well into the 17th century. His contributions to geometry and number theory go well beyond the archimedean tradition. And by promoting the use of experiments in scientific research, al-Haytham played an important part in setting the scene for modern science." Ibn al-Haytham's scientific method was very similar to the modern scientific method and consisted of the following procedures: 1. Observation 2. Statement of problem 3. Formulation of hypothesis 4. Testing of hypothesis using experimentation 5. Analysis of experimental results 6. Interpretation of data and formulation of conclusion 7. Publication of findings

Herman Helmholtz

Hermann von Helmholtz (1821-1894), conducted studies of a wide range of topics that would later be of interest to psychologists. Natural scientist who studied sensation Investigated color vision, hearing, and speed of nerve condition Provided foundation for modern perception research Defined problems of visual and auditory perception that experimental psychologists would study, including Trichromatic theory of color, Unconscious Inference theory of perception, and established a theory of music perception that lasted 100 years

Ernst Weber

He taught anatomy and physiology at the University of Leipzig. His work is on the physiology of sense organs. He worked on skin and muscular sensations. He was originally not interested in psychology but his work contributed a lot in making psychology a science.

Important contributions

Experimental determination of the accuracy of the two-point discrimination of the skin; that is, the distance btw two points that must be spanned before subjects report felling two distinct sensations Two-point threshold; the point at which the two separate source of stimulation can be distinguished First demonstrator of a threshold Just noticeable difference; smallest difference that can be detected btw two physical stimuli; to report whether one felt heavier than the other Subject could make such discrimination much more accurately when they lifted the weights themselves than when the experimenter placed the weights in their hands Suggested that discrimination among sensation depends not on the absolute difference btw two weights but on their relative difference or ratio

Gustav Theodor Fechner

He is considered as the father of psychophysics and experimental psychology. He studied and remained at University of Leipzig Herbart answered the first of Kant's objections by conceiving of mental entities as varying both in time and in intensity and showing that the change in intensity over time could be mathematically represented. Fechner then answered the second objection by developing psychophysical procedures that allowed the strength of a sensation to be scaled. Wundt combined these notions, joined them to the methods of sensory physiology and experimental phenomenology and, in 1879, created the Leipzig laboratory. One such contribution, as we have already noted, was Kant's defining the prerequisites that would need to be met for psychology to become an empirical science. It is in the work of Gustav Theodor Fechner (1801-1887) that we find the formal beginning of experimental psychology. Before Fechner, as Boring (1950) tells us, there was only psychological physiology and philosophical psychology. It was Fechner "who performed with scientific rigor those first experiments which laid the foundations for the new psychology and still lie at the basis of its methodology" Fechner was born in Gross-Sächen, Prussia. At the age of 16 he enrolled in medicine at the University of Leipzig where he studied anatomy under Weber. No sooner had he received his medical degree, however, than his interest began to shift toward physics and mathematics. By 1824, he was lecturing in physics and in 1834, with over 40 publications to his credit, including an important paper on the measurement of direct current, he was appointed Professor of Physics at Leipzig. Fechner's psychological interests began to manifest themselves toward the end of the 1830s in papers on the perception of complementary and subjective colors. In 1840, the year in which an article on subjective afterimages appeared, Between 1851 and 1860, Fechner worked out the rationale for measuring sensation indirectly in terms of the unit of just noticeable difference between two sensations, developed his three basic psychophysical methods (just noticeable differences, right and wrong cases, and average error) and carried out the classical experiments on tactual and visual distance, visual brightness, and lifted weights that formed a large part of the first of the two volumes of the

Wilhelm Wundt

In 1875, Wundt founded a laboratory specifically dedicated to original research in experimental psychology in 1879, the first laboratory of its kind in the world. Wilhelm Wundt, who is often considered the father of experimental psychology, for introducing a mathematical and quantitative approach to experimental psychology in the 19th century. Wundt was the first to call himself a "psychologist", and was also the first research/experimental psychologist. He established the first psychology laboratory in Leipzig and he founded the structuralist school of psychology. His disciples carried on his work, most prominent among them is Titchner.

Titchner

Contribution

Established an association of experimental Psychology called the Experimentalists (1904) which is still in existence today as the Society of Experimental Psychologists. Was an influence in American Psychology bringing a strict empirical, Wundtian approach to experimental psychology. Created a system of Structural Psychology later termed Structuralism a study of the elemental structures of Consciousness based on introspection. Trained 56 doctoral students of which over a third were Women, many rising as prominent Psychologists. Attempted to eliminate stimulus error in the experience of the stimulus.