Psychophysics

1
Psychophysics

• Introduction
• Study of relationship between physical stimuli
  and sensations
• Gustav Fechner
• Three psychophysical problems
• What is the weakest stimulus that can be detected
  (the stimulus threshold)?
• What is the smallest difference between stimuli
  that can be detected (the difference threshold)?
• What is the relationship between intensity of
  stimulus and intensity of sensation?

2
Detection

• Classical psychophysical methods
• Method of constant stimuli
• Method of limits
• Adaptive testing -- staircase method
• The theory of signal detection
• Signal detection methodology
• Outcome matrices
• Sensitivity and criterion measurement

3
Discrimination

• Difference thresholds (jnds)
• Webers Law (DI kI)
• Reaction time (RT) measures
• Simple RT
• Choice RT

4
Identification

• Information theory
• Information reduction of uncertainty
• Quantification of information the bit
• Channel capacity
• Hicks Law Choice RT is a linear function of
  amount of information in the stimulus

5
Scaling

• Quantification of the strength of a sensation
• Prothetic vs metathetic continua
• Indirect scaling Fechners Law
• S k log(I/Io)
• Direct scaling Magnitude estimation and
  Stevens Law
• (S aIm)
• Cross-modality matching
• Multidimensional scaling
• Context and bias Adaptation Level theory