PSYC 427 week 4

minimal pairs

a pair of words that differ by only 1 phoneme (pat/hat) (one sound)

gestures

what articulator moves and how

phonemes vs gestures

Phonemes may not be the minimal unit for production• Instead, gestures (what articulator moves and how) could be considered the minimal units

why are gestures useful?

Thinking in terms of gestures can help link phonology to neural structures like cranial nerves and they can help explain specific production disorders, including those that result in errors that arenot other phonemes (ex: Slurred speech)

spectrograms

Sound is often displayed in spectrograms. • This shows the frequencies (pitch) in the acoustic signal and how they change over time • The colors indicate the amplitude/intensity (loudness)of a given frequency at a given time.

formants

resonant frequencies of the vocal tract that shape the sound of speech and singing. They are the peaks in the frequency spectrum of a speech signal and are crucial for distinguishing different vowels and some consonants

lack on invariance problem

There is no one-to-one correspondence between the acoustic cues and the phonemes perceived. Refers to the challenge in speech perception where the same phoneme (speech sound) can be produced in many different ways, yet listeners still recognize it as the same sound. The issue is that there is no acoustic property that is always associated with a particular phoneme.

variability between speakers

different sizes of vocal tracts lead to different formant values

variability within speaker

can be affected by factors such as: conversational circumstances (casual vs formal or background noise), emotional state, alertness

variability: coarticulation

variability due to surrounding sounds

Resonance

refers to the amplification and modification of sound waves as they travel through a medium. All objects have a frequency they resonate to. Mass and dimensions play a role in determining that frequency

motor theory of speech perception

we perceive speech sounds by simulating the movements required to produce them, rather than simply analyzing their acoustic properties.

mirror neurons

Some group of neurons fire• When an action is performed• OR when watching someone perform that same action• These neurons are called mirror neurons• Found in the premotor cortex and the somatosensory cortex. Mirror neurons are a type of neuron that activates both when an individual performs an action and when they observe someone else performing the same action

Describe why mirror neurons may help explain speech perception

Some have argued that mirror neurons are a potential neural mechanism for the motor theory of speech perception

Altered auditory feedback

refers to a change in the way a speaker hears their own voice while speaking. This can happen in real-time through delays, frequency shifts, or distortions, affecting speech production

Describe the neural basis of detecting altered auditory feedback

When what you hear is different than what you produced, there is activation in the superior temporal gyrus. There are indications that the cerebellum does play a role in the effects of altered feedback. Patients with cerebellar degeneration have reduced responses intemporal-parietal region to altered feedback

Describe how altered auditory feedback affects vocal production

it affects clarity, loudness, and pitch. One of the first indications of a hearing loss is a degradation in the clarity of your speech, appropriately modulating the loudness of your voice is difficult without being able to hear yourself, controlling the pitch of your voice well generally requires being able to hear your own voice