Infant perception 1

Question 1

What challenges do infants face from speech stream?

Answer 1

poverty of stimulus; limited quantity of input, agrammatical, high variable across speakers, no overt cues for segmentation, need to have auditory acuity to break code, and learn sufficient mechanisms and interactions to break

Question 2

What is sound like pre-birth?

Answer 2

cochlear functional at 24-28w (rhythmic distinctions)
ambient noise= 85dB (hydrophone an dHB and blood)
can hear prosody, gender, syllables ad sentence structure

Question 3

at 30-40w can discriminate by HR habituation for…

Answer 3

/i/ and /a/ discim (Zimmer 93)
syllable reversal (bibi/baba) (Lecaneut 87)
gender (Lecaneut 93)
piano note (lecaneut 00)
Mothers voice, language (Kisilevsky 2010)

Question 4

Kisilevsky 2009

Answer 4

HR habituation for novelty of ambient language in chinese different to english (hear prosody)

Question 5

Premature babies miss out on exposure- how do we know?

Answer 5

Webb (2015); ICU on own, vs recorded mothers’ voice; exp group had larger corpus collosum and frontal horn and auditory cortex

Question 6

Evidence infants can hear in womb and recall after birth?

Answer 6

• pref mothers voice over females (deCaspar and fifer 80)
• neighbours theme (deCaspar and Spence 86)
• music (james 02)
  nonsense syllable sounds> bigger MMR response (Partanen 2013)

Question 7

can we test ‘pre-exposure’?

Answer 7

no! children start learning before birth so they are never pre exposure.

Question 8

what is auditory acuity? do children have it at birth?

Answer 8

detecting change in frequency duration and intensity; not efficient at birth as outer and middle ear are less efficient and auditory cortex immature
-measured by masking experiment (distinction between two bandwidths)

Question 9

Frequency resolution- adults comp to infants

Answer 9

Aslin 89: adults= 1% at 1000Hz, 6m infants= 1.5-4% at 1000Hz

Good for low frequency sounds at new born, mature more at 6months for higher frequencies

Question 10

Temporal resolution

Answer 10

Immature in young infants- ability to tell two sounds different in duration which rapidly change over time; Elfenbein 93: might not reach adultlike until 10yo (compared 6,8,10yo)
- at 2 months, only able to tell a 10% discrimination

Question 11

Intensity resolution- absolute threshold?

Answer 11

‘intensity of sound that is just detectable in a quiet environment’
Improvements between 1 and 6 mths, but not at adult levels Improvements continue until later childhood with earlier adult-like thresholds for higher frequencies

Question 12

intensity resolution- intensity discrimination?

Answer 12

‘ability to detect intensity difference between sounds’ poorer distinction at 7-9m:
By 7 to 9 mths, can detect intensity difference of 6 dB between 100 Hz tones, while adults can detect 2 dB difference. By 4 yrs, intensity discrimination close to adult levels

Question 13

Intensity resolution - general

Answer 13

Develops over first 3-4 years; bias to low frequencies but sufficient acuity for important distinctions- (spontaneous response to tones or noise bands at difference frequencies)

Question 14

Attunement for speech sounds?

Answer 14

preference to speech vs non speech at 2-4m (vouloumanos and werker 04/07)
and early preference (newborn and 1m) for IDS rather than ADS- preference looking (Cooper and aslin 90/94)