Chapter 11 Study Questions
Music
1. What does the musical helix illustrate?
Answer: The musical helix illustrates the two characteristics of musical pitch: tone height and tone chroma.
2. What is tone height?
Answer: Tone height is a sound quality whereby a sound is heard to be of higher or lower pitch. Tone height is monotonically related to frequency.
3. What is the difference between consonant or dissonant chords?
Answer: Consonant chords are more pleasing, and they are combinations of notes in which the ratios between the note frequencies are simple. Dissonant chords are less pleasing, and they are combinations of notes in which the ratios between the note frequencies are more complicated.
4. Describe how cultural differences might affect our perception of music.
Answer: Cultural differences might affect our perception of music in that people from various cultures can hear musical notes in different ways. For instance, the Javanese have fewer notes within an octave, and there is greater variation in a note’s acceptable frequencies. On the other hand, western cultures learn to perceive music using octaves that have more notes within them. This difference affects the perception of music in general.
5. Explain what needs to be consistent in a melody, as opposed to what can change in it.
Answer: A melody is defined by the pattern of rises and falls in pitch, and this pattern needs to be consistent. However, the exact notes in the sequence of sound frequencies can vary. For instance, a melody will be perceived as the same even if it is played in a different key than it was originally heard.
6. Provide an example of musical rhythmic grouping.
Answer: An example of musical rhythmic grouping is syncopation. When two different rhythms are overlapped, their patterns can collide in interesting ways. For example, if one rhythm is based on three beats (AaaAaaAaaAaa) and the other on four (BbbbBbbbBbbbBbbb), the first accented sound for both rhythms will coincide only once every 12 beats. Across the 11 intervening beats, the two rhythms will be out of sync.
7. Describe evidence that melody development begins at an early age.
Answer: Studies of 8-month-olds reveals that learning melodies begins early in life. Saffran et al. (1999) conducted experiments in which infants could be trained to attend to new melodies of different sequences of tones.
Speech
8. What is the vocal tract?
Answer: The vocal tract is the airway above the larynx used for production of speech. It includes the oral tract and nasal tract.
9. What are the three basic components to the production of speech?
Answer: The three basic components to the production of speech are respiration (lungs), phonation (vocal cords), and articulation (vocal tract).
10. What does the rate at which vocal folds vibrate depend on?
Answer: The rate at which vocal folds vibrate depends on their stiffness and mass.
11. What is articulation?
Answer: Articulation is the act or manner of producing speech sound using the vocal tract.
12. How are formants specified?
Answer: Formants, which are resonances of the vocal tract, are specified by their center frequency and are denoted by integers that increase with relative frequency.
13. What does a spectrogram illustrate?
Answer: A spectrogram is a visual pattern for sound analysis that provides a three-dimensional display plotting time on the horizontal axis, frequency on the vertical axis, and intensity on a color or gray scale.
14. How are consonant sounds classified?
Answer: Consonant sounds are classified according to three articulatory dimensions: 1) place of articulation; 2) manner of articulation; and 3) voicing.
15. Explain the concept of coarticulation.
Answer: Coarticulation is the phenomenon in speech whereby attributes of successive speech units overlap in articulatory or acoustic patterns. This phenomenon results from the fact that speech production is fast and presents a challenge to understanding speech for both humans and computers.
16. Why is it difficult to build an advanced computer speech recognition system?
Answer: It is difficult to build an advanced computer speech recognition system because the system needs to take into consideration which speech sounds precede and follow each other sound. In addition, the system cannot identify the preceding and following sounds without also taking into consideration which sounds precede and follow them, and so on. This is a difficult task for a computer.
17. What is categorical perception of speech?
Answer: It is the tendency of listeners to label and discriminate various sounds of speech in a categorical fashion. Additionally, in categorical perception the discrimination of items is no better than the ability to label items.
18. What is special about speech according to the “motor theory” of speech perception?
Answer: According to the “motor theory” of speech perception, speech is special because humans have evolved special mechanisms for producing speech, and this aids them in understanding speech as well.
19. How does spectral contrast play a role in the perception of speech?
Answer: Spectral contrast helps listeners perceive speech despite the lack of acoustic invariance due to coarticulation.
20. Describe why it is difficult for Japanese speakers to distinguish between “l” and “r.”
Answer: It is difficult for Japanese speakers to distinguish between “l” and “r” because they have learned to ignore this difference in their native language, as it is not necessary for their language to use this distinction. Once speakers learn to ignore certain acoustic sounds during development, it is difficult for them to learn to perceive these differences later on.
21. What do brain imaging and neural recording studies suggest about the location of speech perception in the brain? Which area(s) are involved in it?
Answer: Brain imaging studies show that both hemispheres of the brain, particularly the temporal lobes, are active during speech perception.