chapter 12: hearing in the environment Flashcards
in sound localization, define auditory space
space: sound coming from different locations in space
what are the 2 types of location cues
- binaural
- spectral
name the 3 dimensions people use to locate the position of a sound
- azimuth (left-right)
- elevation
- distance
define binaural cues and name the 2 types of binaural cues
- interaural level difference (ILD)
- interaural time difference (ITD)
what do we mean when we say our heads are an acoustic shadow
- act as barrier
- reduces intensity of sound that reach the far ear
why is ILD only an effective cue for location of high-frequency sounds
- objects have large effect on sound wave if larger than distance between waves (high-frequency)
- small effect if object smaller than distance between waves (low-frequency)
ILD is based on … while ITD is based on …
difference in sound pressure level
time difference between when sound reaches left and right ear
why is ITD considered the dominant binaural cue for hearing
bc most sounds in environment contain low-frequency components, which can’t be detected by ILD
what is a cone of confusion
place of ambiguity about the elevation of a sound source illustrated by a cone
differentiate binaural and spectral cues
binaural: depends on both ears (left-right pos)
spectral: depends on one ear (diff in distribution of frequency)
explain how the pinnae is important in determining the elevation of a sound
sounds bounce around within the pinna to create diff patterns of freq for 2 locations
explain the experiment that allowed researchers to conclude that different sets of neurons were involved in responding to each set of spectral cues
- Ps with mold that altered shape of pinnae showed poor performance in sound localization
- after 19 days, adapted and able to localize sounds
- when mold taken out, no readaptation period
what is the Jeffress model of auditory localization
neurons are wired to receive signals from both ears
- coincidence detectors (ITD detectors)
when looking at tuning curves, why do we call it place coding for birds, but population coding for mammals
- broadly tuned neurons working tgt (mammals)
- firing of neurons at specific place in NS (birds)
what is the first place that receives signals from the left and right ears
superior olivary nucleus
what happens if the auditory areas are lesioned
inability to localize sounds
what is the what auditory pathway and from where does it extend
- extends from anterior belt area → front of temporal lobe → frontal cortex
- perceives complex sounds and patterns of sound
what is the where auditory pathway and from where does it extend
- extends from posterior belt area → parietal lobe → frontal cortex
- localizing sound
differentiate direct and indirect sounds
direct: reaches your ears directly
indirect: reaches your ears after bouncing off walls, ceilings, and floor
what is the precedence effect
perceiving sounds as coming from near the source that reaches our ears first
when are lagging sounds perceived as echoes
when the delay between lead and lag sounds too long
in larger rooms, are the delays shorter or longer
longer
what are architectural acoustics
study of sounds that are reflected in rooms
name the two major factors that affect indirect sounds
- size of room
- amount of sound absorbed by walls
