Jenny detects a change in brightness when a 25W light bulb is replaced with a 100W light bulb but not when it is replaced with a 50W light bulb.However,she detects a change if the same 50W light bulb is replaced with a 200W light bulb.The differences in Jenny's ability to perceive these changes can be explained by
A)the Stroop effect.
B)Thorndike's law.
C)the Ponzo illusion.
D)Weber's law.

Question

Quizplus · Accepted Answer

This scenario demonstrates Weber's law, which states that the smallest noticeable difference in stimulus intensity (i.e., the just noticeable difference, or JND) is a constant proportion of the initial stimulus intensity. In this case, the difference between the 25W and 100W light bulbs exceeds the JND, while the difference between the 25W and 50W bulbs does not. The same is true for the difference between the 50W and 200W bulbs. This suggests that the JND for brightness is a constant proportion of the initial brightness, which is in line with Weber's law.

Jenny Detects a Change in Brightness When a 25W Light