1. Weber and Fechner Psychophysics

2. Afterimages Examples of some of the illusions with which Fechner worked. Examples of some of the illusions with which Fechner worked.some of the illusions some of the illusions Try them on the classroom computers. Note when you see color etc… Try them on the classroom computers. Note when you see color etc…

3. Weber's Law (S2-S1)/S1 = K, where S2-S1= jnd (S2-S1)/S1 = K, where S2-S1= jnd Let us suppose that we are working w/ the perception of differences in weight, and the measure is paperclips. Let us suppose that: S1=2, S2=4, then K=1 Let us suppose that we are working w/ the perception of differences in weight, and the measure is paperclips. Let us suppose that: S1=2, S2=4, then K=1 How many paperclips do you need to feel they were heavier than 4 paperclips? Etc… How many paperclips do you need to feel they were heavier than 4 paperclips? Etc…

4. Sensation-Perception data Sensation (S) (geometric scale) Sensation (S) (geometric scale) 2 4 8 16 16 32 32 64 64 128 128 Perception (P) (arithmetic scale) 1 2 3 4 5 6 7 P=log S in base (K+1)

5. jnd Sensation-Perception graph

6. Weber's function, mind and body S= sensation = sensory organ = body S= sensation = sensory organ = body P= perception = mind P= perception = mind Hence:the mind and the body are different and separate, follow different laws Hence:the mind and the body are different and separate, follow different laws And: The mind and the body are connected by a mathematical relationship. And: The mind and the body are connected by a mathematical relationship. Thus: The mind can be studied scientifically. Psychology can be a science. Thus: The mind can be studied scientifically. Psychology can be a science.

7. Yippee! The nightview and the dayview can be reconciled. The nightview and the dayview can be reconciled.

8. Psychophysics The study of the relation between the body and the mind, in matters of sensation and perception. The study of the relation between the body and the mind, in matters of sensation and perception. Fechner is the founder of this branch of psychology. Fechner is the founder of this branch of psychology.

9. Esthetics What makes something beautiful? What makes something beautiful? Is it a question of proportions? Is it a question of proportions? Fechner is one of the first people to address the question experimentally.

10. The end