[You may want to bring a calculator, small ruler, and good-quality eraser to the exam.]

1. What was Fechner trying to accomplish when he founded psychophysics? From his viewpoint, what is the absolute threshold and why is it important?

2. How do you determine the absolute threshold, using the Method of Limits and the Method of Constant Stimuli? How are the methods similar and how are they different?

3. Using the Method of Constant Stimuli, explain how a psychophysical function is produced. Draw a typical psychophysical function, label the axes, and explain how an absolute threshold is determined. What does Signal Detection Theory have to say about this approach to defining an absolute threshold?

4. Explain the difference in procedures between a Signal Detection experiment and a Method of Limits/Constant Stimuli experiment.

5. Explain the matrix of possible outcomes for a trial in a Signal Detection experiment.

6. According to Signal Detection Theory, our tendency to say "Yes, I detected it" is controlled by our criterion or decision rule (bias, beta) and our sensitivity to the difference between the event being there or not (d�). Explain how outcome matrices should be examined to separate these two factors.

7. What is a ROC curve? Practice drawing curves from data and interpreting them. (Don't forget to label the axes, and explain the meaning of the diagonal line.) Practice drawing curves which indicate differences in sensitivity.

8. What is a difference threshold?

9. Describe how a psychophysical function for a difference threshold is created. Be able to determine, label, and explain the reasoning behind such terms as the Point of Subjective Equality, the Interval of Uncertainty, and the Just Noticeable Difference.

10. Define Weber�s Law. Be able to interpret JNDs. Be able to compute a JND using Weber�s Law.

11. Define Fechner�s Law. Be able to explain how the law related perceptual experience and changes in the physical world.

12. Explain the magnitude estimation procedure and how the results from that procedure are used in Stevens' Power Law.

13. Be able to predict or interpret the meaning of various exponents derived from Stevens' Power Law on the form of the psychophysical function.

14. Compare and contrast Stevens and Fechner�s approach to the definition of units on psychological scales.