L33 Psych 100B Lecture Notes - Lecture 50: Functional Magnetic Resonance Imaging, Positron Emission Tomography, Absolute Threshold
4 Nov 2018
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Present an orderly series of stimulus intensities to the subject: 2. At each presentation: did the subject detect the stimulus: (cid:1007). Threshold=(cid:373)idpoi(cid:374)t (cid:271)et(cid:449)ee(cid:374) i(cid:374)te(cid:374)sities (cid:449)here the su(cid:271)je(cid:272)t"s respo(cid:374)se changed. Use a fixed set of stimulus intensities selected in advance (there should. Be intensities at each extreme that are clearly above and below threshold: 2. Present stimulus intensities in a random order: 3. In reality, there is a gradual transition from perceiving 0% to perceiving. Use pre-selected set of stimulus intensities presented in a random order: 2. On each trial present two stimuli one is the standard, used as a reference stimulus and the other is the comparison, where the intensity varies from trial to trial: 3. If 25% is the weight of 14 pennies and 75% is 16 pennies then the difference threshold is 15 pennies: staircase method streamlined way of finding a threshold, 1. Begin with an intensity far below (or above) the threshold: 2.
