Lecture 6 - Speech

Question 1

KE family?

Answer 1

• Fisher et al 1998 found the half of the KE family show severe speech and language disorder
• pattern of inheritance of their disorder suggested mutation of a single gene = FOXP2 gene on chromosome 7

Question 2

FOXP2 gene?

Answer 2

• is a regulator gene = controls other genes to provide entry points into neural pathways
• is necessary for development of speech and language but is not a gene for speech
• has many different functions and is also important in communication
• has a long evolutionary history
• is only a part of the genetic puzzle of language

Question 3

Anatomical mechanisms for speech?

Answer 3

• our vocal tract anatomy moves in highly dynamic ways
• evolution of the extended larynx allows for considerable vocal flexibility
• primates have less control over their vocal anatomy and are limited in their ability to produce new sounds
• however there is evidence for some vocal control = mechanisms for speech have deep evolutionary roots

Question 4

What is the motor theory of speech perception?

Answer 4

• developed by Lieberman et al. (1960)
• 3 main claims:
  1. speech perception is innate
  2. speech perception is human-unique
  3. speech perception involves perception of vocal tract gestures

Question 5

What is the auditory theory of speech perception?

Answer 5

• speech perception is based primarily on acoustic properties of speech
• 3 main claims:
  1. perception is dependent on auditory mechanisms
  2. speech perception is not uniquely human
  3. speech perception can be shaped through genetics and learning

Question 6

Is speech perception innate?

Answer 6

• Eimas et al carried out categorical speech perception in infants
• supported motor theory = perception driven by innate knowledge of production
• supported auditory theory = perception driven by innate auditory perception

Question 7

Is speech perception human unique?

Answer 7

• no other species can show categorical speech perception

Question 8

Primate speech perception?

Answer 8

• Panzee (a language trained chimpanzee) knows 128 words
• evidence also comes from Kanzi
• shows experience is critical for speech perception
• supports auditory theory

Question 9

Is speech perception based on knowledge of vocal tract gestures (articulation)?

Answer 9

• mcGurk effect = interaction between hearing and vision
• knowledge of visual mouth movements facilitates speech perception
• phoneme categorisation is influenced by visual information of mouth movements (motor cues)
• supports motor theory
• inconsistent with auditory theory, but learning could play a role