HOW DO WE PERCEIVE PITCH??! BY: DEJONA HAWKINS PRD. 7

HIGH PITCHED: LOW PITCHED: Chirp of a bird Roar of a truck

Place theory We hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane

High frequencies produce large vibrations near the beginning of the cochlea’s membrane, low frequencies near the end.

Frequency theory Suggests an alternative explanation for how we detect pitch How we perceive low pitch sounds Depends on sound waves Also known as the theory.

Individual neurons can’t fire faster than times per second!!!

Like soldiers who alternate firing so that some can shoot while others reload, neural cells can alternate firing.

How do we locate sounds??!

Sound waves strike one ear sooner and more intensely than the other.

WHY DON’T WE HAVE ONE EAR??! “THE BETTER TO HEAR YOU”

Allows you to enjoy stereophonic hearing!

TWO EARS ARE BETTER THAN ONE 4 THIS REASON IF A CAR TO THE RIGHT HONKS, YOUR RIGHT EAR RECEIVES A MORE INTENSE SOUND AND IT RECEIVES SOUND SLIGHTLY SOONER THAN YOUR LEFT EAR.

SOUND TRAVELS 750 MPH OURS EARS ARE 6 INCHES APART INTENSITY DIFFERENCE AND TIME LAG ARE EXTREMELY SMALL

LAST DO YOU THINK WE DO WELL WITH HEARING A SOUND FAR AWAY THEN A SOUND AHEAD, BEHIND, OVERHEAD OR BENEATH?? The answer is….

EXAMPLE

SOME BRAIN NEURONS RESPOND MORE TO A HIGH-CONTRAST SOUND STIMULUS, AS MIGHT BE MADE BY A MUSICAL INSTRUMENT PLAYING SOLO OTHERS RESPOND MORE TO LOW-CONTRAST SOUND, AS WOULD BE MADE BY THE SAME INSTRUMENT PLAYING IN AN ORCHESTRA.