When walking, Lisa, an eighteen-year-old with blindness, has learned to attend to the subtle changes in pitch of echoes from objects as she moves towards them. Which phenomenon is responsible for these changes?
A)obstacle sense
B)Doppler effect
C)echolalia
D)tactual perception

Question

Quizplus · Accepted Answer

The Doppler effect is responsible for the changes in pitch of echoes as Lisa moves towards objects. This is due to the compression of sound waves as they bounce back towards her, creating a higher frequency (and therefore higher-pitched) sound. This phenomenon is similar to the changes in pitch of a siren as an ambulance or police car approaches and then passes by.

When Walking, Lisa, an Eighteen-Year-Old with Blindness, Has Learned to Attend