AP® Psychology

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Why Not Notice a Rubber Snake?


Howard wants to play a trick on his older sister. He first sneaks a rubber snake into her almost-empty purse, but she notices it is heavier immediately and his plan fails. He then puts it into her already very-full backpack, and she doesn't realize it until she opens up her bag in English.

Why doesn't his sister notice the extra weight of the snake amidst her AP Psych, Calculus, and Botany materials when she DID notice it next to her car keys?


Women's absolute thresholds changes dramatically from situation to situation.


His sister has synesthesia.


The sense of touch is not very sensitive to changes.


It takes longer to habituate to less-intense stimuli than it does to more intense ones.


The amount required to reach a just noticeable difference (jnd) is not constant; it depends on the difference proportionate to what is already being sensed.