Week 1 Flashcards
Principles of cognition
Attention
▫ The selection of important information and focusing on specific voices among others
• Memory
▫ The mental faculty of retaining and recalling past
experience; short- and long-term storage of
information in the brain
• Learning
▫ The act, process, or experience of gaining knowledgeor skill implicitly or explicitly
• Dynamic interactions between:
▫ perception of incoming sensory information
▫ previously acquired knowledge stored in memory
Functions of perception?
Sample information from the environment ▫ Organize sensory information ▫ Complete missing information ▫ Use previously acquired experience to interpret ambiguous information within a given context • i.e., perception is never neutral
Perception involves capturing information from the sensory environment and
processing it to make sense of the world around us. There is a lot of processing that depends on the surrounding context, the amount of information simultaneously
present in the environment, the structure of the information coming from the
environment, and our past experience. So perception not only samples the
information from the environment, but organizes it in terms of objects and events,
completes information that is missing because it is masked by other information in
the environment, and interprets what the whole set of incoming information meansto us.
Developmental aspecests of conceptual concept
me aspects of conceptual knowledge are innate or emerge very early in development, while others are acquired throughlearning and inference.
Perception relies of global context, what potential errors can occur?
Certain local relations can lead us to make errors in interpreting global relations. Think of shapes or finger like images shown in first class
What sorts of similar effects are produced in music, where musical materials (e.g.,
melody, rhythm, timbre, harmony) can have different perceptions (e.g., consonance,dissonance, according to harmonic context)?
Here is an acoustic event formed of two piano notes (a musical interval). In the first
context of Db major, it is perceived as consonant, stable and as a major third). In the
second context of D minor, this same acoustic event is perceived as a diminished
fourth, an interval that is tonally dissonant and unstable. The F above the C# could actas a 4-3 suspension that requires a resolution to E (the third above C#). The lowest
staff illustrates the resolution, followed by the tonic on D.
The perception of loudness (or playing effort) depends not only on _________ but _____________?
sound level, but
also on the ratio of direct to reverberant sound energy (related to the distance of thesound source) and especially on the timbre of the sound, which varies a lot with
playing effort.
What is the quintina?
The combination of acoustic information coming from 4 men’s voices produces bandsof energy in the high frequencies that are falsely recognized as a 5th high voice (the
quintina, which, according to Sardinian tradition, represents the virgin Mary who
comes when the men sing just right). The voice is not present as a sound source, but
the acoustic pattern corresponds to our knowledge of voices and the auditory image
of the quintina is constructed by our brains. The effect is very delicate because it
requires a perfect tuning of the pitches and the timbres of the four original voices,
which is very difficult to achieve.
Why and how does Psychological science measure things indirectly?
one cannot directly measure
what someone is perceiving or thinking or imagining with any measuring instrument.The process is indirect because we present a perceiver with some stimulus (e.g.,
sound, word, picture, vibration or sequence of these) and we ask them to answer a
specific question (is sound 1 higher or lower or louder or softer or duller or brighter
than sound 2? By how much? Are these two melodies in the same key? Do they have the same underlying harmony?). We then “infer” what is going on in that person’s
head by trying to relate what we put in with what they respond. The aim is to
understand the structure of processing that goes on inside the “black box.”
Sound waves are formed by areas of
condensation (compression) and areas of
rarefaction (decompression) of air molecules that move through space at a constant velocity (the speed of sound, roughly 340 m/s or 1100 ft/s). This causes variations inair pressure (higher in areas of condensation and lower in areas of rarefaction). The
changes in pressure are induced by a vibrating object in the environment. If the
variation between condensation and rarefaction is very regular (e.g., changing like a sine function as in the figure), one can determine the wavelength of the acoustic
wave, i.e. the space occupied by a complete cycle between peaks of condensation.
A sine tone, or sinusoidal wave, is?
the simplest form of vibration expressed visually as a variation in amplitude or displacement over time. The curve represented in the
graph is called a waveform. There are several properties of a sine wave that can be
described. One is its maximum amplitude, related to how loud the sound is. Another
is the particular point in the repeating cycle, called the phase, which can be
expressed in terms of degrees for a sine wave: a full cycle covers 360 degrees, just
like a circle. Another one is the time it takes to complete one cycle, or one period, of
the waveform. This is generally called its period and is expressed in seconds per cycle.
Another way to express the period is
by its inverse, called its frequency. Period is
expressed as seconds/cycle and frequency is expressed as cycles/second or Hertz
(named after the German physicist Heinrich Hertz; the Hz unit has been part of the
international metric system since 1933). So when someone talks about the tuning Aas being A 440, they are referring to the frequency that produces an A, which is 440 Hz.
A graph with the level or amplitude or intensity on the y-axis and the frequency on the x-axis is called?
A frequency
spectrum and was developed by French mathematician Joseph Fourier. For a sine
wave, there is only one frequency, and so all you see is a single line at the appropriatepoint along the frequency scale. The position along the x axis is the frequency, and
the height is the level of the sound.
What is the decibel scale?
Raw sound pressure is measured in microPascals. The threshold of hearing for a 1000 Hz sine tone is about 20 µPa. The way we hear changes in level is along a ratio scale. This means that if I have Sound A at a given pressure and I double it to produce Sound B, and then I double that to
produce Sound C, I will have the same ratio of levels between A and B and between B and C, a ratio of 2; the change in perceived level will be
about the same for both. To take this fact into account, a measure of sound level was developed on a ratio scale that has units of decibels
(abbreviated dB). This scale has constant change in dB for a given ratio between pressures. Another feature of this kind of scale is that it is
logarithmic, as can be seen by the formula. Note that the decibel scale is always relative to something, it takes a ratio of two things to get
decibels. In physics, a reference level has been established, which is 20 µPa, very near the threshold of hearing for middle range frequencies. So when someone talks of Sound Pressure Level in decibels, they are referring to this standardized reference.
Sounds usually start and stop and have a shape in their amplitude variation over time called?
This is called the amplitude envelope. It is generally a slower variation than the
waveform itself. Notice in the left hand panels how the sine wave always has the
same period in all the sounds, but the maximum amplitude varies over time. The
right hand panels show the effect of the envelope shape on the frequency spectrum.Starting and stopping the sound makes the sound energy spread into adjacent
frequencies to a greater or lesser extent depending on the form of the amplitude
envelope.
What are harmonic tone complexes?
Sine tones are also called pure tones, because they contain only one frequency. If youadd other frequencies that are integer multiples of a base frequency, called the
fundamental frequency, you get more complex waveforms that still have the same
period, that of the fundamental frequency. Frequencies related by integer multiples
are called harmonics, and the tones produced by adding them together are called
harmonic tone complexes.
