Speech Perception

Question 1

Categorical Perception

Answer 1

“Categorical perception is the perception of different sensory phenomena as being qualitatively, or categorically, different

Occurs for many consonants but not so much for vowels.

Occurs when “a change in some variable along a continuum is not perceived as gradual, but as instances of discrete categories”
CP occurs whenever perceived within-category differences are compressed and/or between-category differences are separated,

Question 2

Example 1: categorical perception of the ba / da continuum

Answer 2

B and D are two voiced stops differing by their place of articulation:
• B is bilabial
• D is alveolar
• Affects the second formant:

Question 3

Experimental evidence of CP

Answer 3

Set up a continuum of sounds between two categories Run and identification experiment. Run a discrimination experiment.

Question 4

Categorical Perception & the speech mode of perception

Answer 4

For most “ordinary” continua, such as frequency, loudness, brightness etc, our ability to discriminate far exceeds our ability to label

Question 5

Is speech CP unique to humans? 1. Identification

Answer 5

No - Chinchillas and quails show the same VOT boundary as humans for the /da/ - /ta/ continuum.

Question 6

Is speech CP unique to humans? 2. Discrimination

Answer 6

Macaques show discrimination peaks at human VOT and place-of-articulation boundaries. So – suggests that human speech exploits low level discontinuities in the way that vertebrate auditory systems represent sound…

Question 7

Is CP innate or acquired?

Answer 7

We know that infants are born with ability to make many speech discriminations that they can subsequently NOT make.
Animals can make many of these (due to low- level auditory processing).
Adults (and 1-year-old infants) lose the ability to make distinctions that their language does not use.
CP is acquired by reduction of perceptual sensitivity within native phoneme boundaries.
Sensitivity can be re-acquired with intensive training. Therefore not “atrophy”.

Question 8

Phonetic v.s. Phonemic sounds

Answer 8

Phone(phonetic sound)=a particular sound used by any language e.g. the sound [r] or the sound [l]
• Phoneme(phonemic sound)=a sound used in contrast to another in a particular language e.g. the category /r/ as distinct from /l/
Phoneme=group of different phonetic sounds which speakers of a language perceive as the SAME sound (called allophones).
• Different languages make different phonemic contrasts.

Question 9

Minimal pairs

Answer 9

i.e. since in English “lice” and “rice” have a different meaning, then they contain different phonemes: /l/ and /r/ which constitute a minimal pair.

Question 10

McGurk effect

Answer 10

we’re hearing BA which is produced labialy but when we are reading his lips we are hearing GA which is produced more lower back. We’re trying to guess where it is produced