[Bring a calculator, small ruler or straight-edge, 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, the Method of Constant Stimuli, and the Method of Adjustment? 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 the absolute threshold is calculated. (What does Signal Detection Theory have to say about this approach to defining an absolute threshold?)

4. What is a difference threshold? How are the data collected? How are the results plotted?

5. Draw the psychophysical function for a difference threshold. Be able to determine, label, and explain the reasoning behind such terms as the Point of Subjective Equality, Upper Difference Limen, Lower Difference Limen, the Interval of Uncertainty, and the Just Noticeable Difference.

6. What is Weber's Law? Explain the meaning of the mathematical formula. Be able to interpret JNDs. Be able to compute a JND using Weber’s Law.

7. What is Fechner's Law? Explain the meaning of the mathematical formula. What are the units of his scales? What does the shape of the function tell us about the fundamental relationship between perceptual experience and changes in the physical world?

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

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

10. Compare and contrast Stevens' and Fechner’s approach to the definition of units on psychological scales.

11. Know the difference in procedures between a Signal Detection experiment and the classical absolute threshold experiment.

12. Know the matrix of possible outcomes for a trial in a Signal Detection experiment.

13. 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’). Know how outcome matrices should be examined to separate these two factors.

14. What is a ROC plot? What is on the axes? What is the meaning of the diagonal line? Practice plotting data and interpreting the results. Practice interpeting curves and points which indicate differences in sensitivity vs. differences in strategy.