Task 9 - Speech perception Flashcards
Acoustic stimulus (or acoustic signal)
Speech sounds are produced by the position or the movement of structures within the vocal apparatus, which produce patterns of pressure changes in the air called the acoustic stimulus, or the acoustic signal – The acoustic signal for most speech sounds is created by air that is pushed up from the lungs past the vocal cords and into the vocal tract
Articulators
by moving this the shape of the vocal tract is altered – it includes structures such as the tongue, lips, teeth, jaw, and soft palate
Formants
the frequencies at which these peaks occur
Sound spectrogram
the formants for the vowel /ae/ are shown in the sound spectrogram – it indicates the pattern of frequencies and intensities over time that make up the acoustic signal
Formant transitions
rapid shifts in frequency preceding or following formants – and they are associated with consonants
Coarticulation
the overlap between the articulation of neighboring phonemes
Perceptual constancy
the fact that we perceive the sound of a phoneme as the same even though the acoustic signal is changes by coarticulation
Categorical perception
occurs when stimuli that exist along a continuum are perceived as divided into discrete categories
Voice onset time (VOT)
the continuum in categorical perception – the time delay between when a sound begins and when the vocal cords begin vibrating
Phonetic boundary
the VOT when the perception changes from /da/ to /ta/ - when one is not sure between which sound one hears
Multimodal
our perception of speech can be influenced by information from a number of different senses
McGurk effect
it illustrates that although auditory information is the major source of information for speech perception, visual information can also exert a strong influence on what we hear
Audiovisual speech perception
the influence of vision on speech perception
Phonemic restoration effect
participants listen to a recording of the sentence “The state governors met with their respective legislatures convening in the capital city.” Warren replaced the first /s/ in “legislatures” with the sound of a cough and told his subjects that they should indicate where in the sentence the cough occurred. None of the participants identified the correct position of the cough, and, even more significantly, none noticed that the /s/ in “legislatures” was missing
Speech segmentation
the perception of individual words in a conversation - separation of the continuous stream of words
Transitional probabilities
the way sounds follow one another in a language – the chance that one sound will follow another sound baby often follows the word pretty - also with letters, like x is not likely to follow x buth h is likely to follow a t (phonemes)
Indexical characteristics
characteristics that carry information about speakers such as their age, gender, place of origin, emotional state, and whether they are being sarcastic or serious
Aphasia
damage to specific areas of the brain causes language problems
Broca’s aphasia
patients with damage to the broca’s area in the frontal lobe – They have labored and stilted speech and can only speak in short sentences. They are, however, capable of comprehending what others are saying (can include it in these pathways but cannot say it only has to do with where – where pathway)
Wernicke’s aphasia
patients with damage to the Wernicke’s area in the temporal lobe – They can speak fluently, but what they say is extremely disorganized and not meaningful. These patients have great difficulty understanding what other people are saying. In the most extreme form of Wernicke’s aphasia, the person has a condition called word deafness, in which he or she cannot recognize words, even though the ability to hear pure tones remains intact (what pathway)
Voice cells
(recorded from neurons in the monkey’s temporal lobe – part of the what processing stream for hearing) respond more strongly to recordings of monkey calls than to calls of other animals or to “non-voice” sounds - respond only to human voices
Dual-stream model of speech perception
has proposed a ventral (or what) pathway starting in the temporal lobe that is responsible for recognizing speech, and a dorsal (or where) pathway starting in the parietal lobe that is responsible for linking the acoustic signal to the movements used to produce speech (an addition to the streams that already exist)
Motor theory of speech perception
This theory proposes that (1) hearing a particular speech sound activates motor mechanisms controlling the movement of the articulators, such as the tongue and lips, that are responsible for producing sounds; and (2) activation of these motor mechanisms, in turn, activates additional mechanisms that enable us to perceive the sound. Thus, the motor theory proposes that activity of motor mechanisms is the first step toward perceiving speech
