1. Copyright © Allyn & Bacon 2008 Chapter 10 - Psychophysics and the Formal Founding of Psychology A History of Psychology: Ideas and Context (4 th edition) D. Brett King, Wayne Viney, and William Douglas Woody This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease, or lending of the program

2. Copyright © Allyn & Bacon 2008 Psychophysics Psychophysics is the study of the relationships between the properties of stimuli and the psychological impressions of those stimuli. Early researchers in psychophysics studied thresholds. –Upper and lower absolute thresholds were operationally defined as the minimal or maximal stimulus intensity that is detected 50 percent of the time. –Researchers also investigated difference thresholds, the minimal stimulus difference that is detectable 50 percent of the time. Researchers studying two-point thresholds in the skin senses developed the aesthesiometer. Psychophysicists pioneered the quantification of certain mental processes. –They demonstrated lawful relationships between physical stimuli and the psychological impressions of stimuli.

3. Copyright © Allyn & Bacon 2008 Psychophysics Ernst Heinrich Weber studied the sense of touch. –He demonstrated that different locations on the body have different two-point thresholds. –Weber’s Illusion refers to the illusory experience of two points when they are moved over insensitive or sensitive areas of the skin. –Weber pioneered research into difference thresholds, seeking the just noticeable difference (jnd) between stimuli in a variety of modalities. –He formulated Weber’s law to describe the relationship between physical and experienced differences.

4. Copyright © Allyn & Bacon 2008 Psychophysics Gustav Theodor Fechner struggled throughout his life with the mind-brain problem. –He wrestled with his night view of extreme materialism and his day view of panpsychism. He wrote his day view under the pseudonym of Dr. Mises. –Fechner reformulated Weber’s law as a log relationship called Fechner’s law. –Fechner developed new methodologies in psychophysics. The method of limits The method of constant stimuli The method of average error –His methods are still taught in experimental psychology programs.

5. Copyright © Allyn & Bacon 2008 Experimental Physiology Rudolph Hermann Lotze wrote the first book in physiological psychology. –He pioneered work in the perception of space and depth. Hermann von Helmholtz was an innovator in physics, physiology, and psychology. –He rejected vitalism and argued that psychological phenomena are physical in nature. –He conducted extensive research in visual perception. –He developed new methodologies and new instruments. The ophthalmoscope. –He argued that infants learn about their sensory worlds through extensive experience and unconscious inferences. –He developed the stereoscope and studied depth perception and binocular vision. –His ideas joined with the work of others in the development of the trichromatic theory of color vision. –He did pioneering work in the physics, physiology, and psychology of auditory perception and music.

6. Copyright © Allyn & Bacon 2008 The Formal Founding of Psychology Wilhelm Wundt receives credit for the formal founding of psychology in 1879 at the University of Leipzig. –His tremendous scholarly productivity provided was critical for the success of the new discipline.

7. Copyright © Allyn & Bacon 2008 The Formal Founding of Psychology The name Wundt preferred for his system of thought was Voluntarism. –Wundt argued against interactive dualism and against hylozoism. –Wundt’s laboratory work employed a rigorous introspection. –His larger vision is broader, including methods such as naturalistic observations, archeological methods, and historical approaches. –Wundt emphasized psychological causality, flexible goals and means, and adaptability. –Voluntary behavior, for Wundt, does not imply free behavior. He argued that some free will is possible through reflective self- consciousness. –Wundt agreed with Darwin’s ideas of adaptation, but Wundt placed far greater emphasis on psychological adaptation.

8. Copyright © Allyn & Bacon 2008 The Formal Founding of Psychology Wundt’s laboratory work is one phase of Wundt’s larger psychological perspective. –Wundt’s laboratory work involved rigorous approaches to modest problems in physiological psychology and sensation and perception. –He emphasized precise measurement. His Volkerpsychologie was much more broad.

9. Copyright © Allyn & Bacon 2008 Voluntarism Some key concepts in Wundt’s psychological system follow. –Wundt defined psychology as the science that investigates “the facts of consciousness.” Psychology must discover the elements of consciousness. –Then psychology must discover possible combinations of elements. An element, in Wundt’s psychology, was a simple sensation. Wundt defined sensation as an element of consciousness and perception as a combination of outward sense impressions. An idea referred to combinations that may arise from memory, early associations, and other sources. He questioned the distinction of ideas and perceptions.

10. Copyright © Allyn & Bacon 2008 Voluntarism Some key concepts in Wundt’s psychological system. –Association is the passive combination of elements. –Apperception is the active combination of elements. –Wundt argued for a tridimensional theory of feeling involving pleasure and pain, strain and relaxation, and excitation and quiescence. –Wundt accepted the principle of creative synthesis. This is the belief that there is real novelty and creativity in higher mental operations. He argued for heterogony of ends, the emergence of new motives during the course of a chain of activities.

11. Copyright © Allyn & Bacon 2008 Wundt’s Legacy Wundt’s legacy continues. –His leadership guided the emergence of psychology. –His research findings held up well over time. –Wundt mentored many students. Emil Kraepelin advanced a theory of schizophrenia based in Wundt’s system and argued against psychoanalysis. –Kraepelin also argued against psychoanalysis. Lightmer Witmer applied Wundt’s ideas to pain and to the special learning problems of children with mental disabilities. –He opened the first clinic run by a psychologist. –He was the first to see scientific psychology as the basis for a helping profession.