Basic Auditory Functions
Demonstrations (Direct Links)
Demonstration 10.1 The Missing Fundamental
Demonstration 10.2 Context and Loudness
Demonstration 10.3 Relationship Between Frequency and Loudness
Demonstration 10.4 Auditory Beats
Before You Start
•
Background: Early Theories of Pitch Perception
Developments in Place Theory
Developments in Temporal Theory
How Do We Hear Pitch?
The Complex Relationship between Frequency and Pitch
Measuring Pitch
How Do We Perceive Loudness?
The Complex Relationship between Amplitude and Loudness
Intensity Discrimination
Measuring Loudness
Sources of Information for Sound Localization
• Physics Today on the Web has an article about auditory localization.
Physiological Basis of Auditory Localization
Measuring Localization Accuracy
Auditory Localization Without Binaural Cues
Nonhuman Localizing Abilities
• Link - You can learn a lot more about bats (videos, pictures, sounds) at the following sites:
Bat Conservation International (Merlin Tuttle)
Bat Bombers--an aborted attempt to use bats for military purposes
USGS Western Ecological Research Center
Wildlife Online
Australian Museum
University of Michigan Museum of Zoology
Batbox (mainly links)
Integrating Vision and Auditory Localization
Perception of Simultaneous Sounds
Perception of Tone Combinations
Masking
Noise
• Link - OSHA noise guidelines
1. Discuss the place and temporal theories of pitch perception, reviewing the evidence in support of each theory. Point out the problems with both theories, and illustrate ways in which they both contribute to pitch perception.
2. In the auditory tuning curves shown in Figure 10.2, notice that the curves
are sharper for high-frequency tones, and that the curves are steeper to
the right than they are to the left. Can you use what you know (especially
Figure 10.1) to explain these phenomena?
3. Discuss why pitch is not perfectly correlated with frequency. Consider
the factors that influence pitch perception. Repeat this same process with
the relationship between loudness and intensity, including a discussion of
the impact of frequency on loudness.
4. Using the equal loudness contours (Fletcher-Munson curves), answer the
following questions:
a. for a 1000-Hz tone at 40 dB, what sound pressure
will be equally loud for a 300-Hz tone? A 50-Hz tone?
b. for a 1000-Hz tone at 100 dB, what sound
pressure will be equally loud for a 150-Hz tone? A 50-Hz tone?
5. Discuss the ways in which sound intensity and sound frequency might be
measured, and contrast this with the ways in which pitch and loudness are
measured.
6. Notice a sound in your present environment and list the cues that help
you judge the direction of the sound source. What are the factors that could
help you resolve potential ambiguities about the location of that sound?
Using only intensity differences, what frequency range would best be localized
by a mouse, a human, and an elephant?
7. Our perception of space is unitary—auditory and visual information
provide us with consistent detail about the world. Compare the information
we discussed in Chapter 6 on visual space perception with what you have learned
in this chapter. How do you think the information might be integrated?
8. Consider the auditory systems of echolocating creatures such as bats and
dolphins. How do they differ from humans? Try to describe what it would be
like to perceive the world entirely through echolocation (cf. Nagel, 1974).
9. Discuss the difference between monaural and binaural beats. How might
monaural beats be helpful to musicians tuning instruments?
10. Consider the combination of visual stimuli (e.g., additive color mixing)
discussed in earlier chapters and the combination of auditory stimuli (e.g.,
combining pure tones, masking, noise) discussed in this chapter. How does
the visual system differ from the auditory system in encoding these combined
stimuli? How might those differences lead to perceptual differences?
Link - The Acoustical Society of America maintains a site with useful information, publications, and resources (e.g., listen to a whale call). The best resource they provide is a CD of auditory demonstrations from the more basic (e.g., loudness scaling, interrelationship of pitch and intensity) to the more esoteric (e.g., missing fundamental, Shepard tones, Deutsch's music illusion).
Link - Albert Bregman's Lab page is a useful site, especially regarding Auditory Stream Analysis. Bregman and Ahad have produced a 62-min CD (Demonstrations of Auditory Scene Analysis: The Perceptual Organization of Sound) that is available from the site. You can even listen to samples of some of the auditory demonstrations directly from the site.
Link - The vOICe site illustrates one possible auditory assistive device for people who have visual impairments.
Link - Echolocation in humans...Ben Underwood video.
Link -
Bregman, A. (1990). Auditory Scene Analysis: The perceptual organization of sound. MIT Press.
Cook, P. R. (Ed.) (1999) Music, cognition, and computerized sound: An introduction to psychoacoustics. Cambridge, MA: MIT. (With CD of demos)
Middlebrooks, J. C. & Green, D. M. (1991). Sound localization by human listeners. Annual Review of Psychology, 42, 135-159.
Neuhoff, J. (2004). Ecological psychoacoustics. Academic Press.
Plack, C. J. (2005). The sense of hearing. Erlbaum.
Yost, W. A. (2006). Fundamentals of hearing, 5th Ed. Academic Press.
