development of auditory perception Flashcards
when is the onset of hearing?
week 28 of gestation/ 7 mths
what is the evidence for auditory stimuli eliciting a response?
- changes in heart rate
- eyeblinks
- gross motor responses
- auditory brain stem responses
what evidence is there to suggest preferred sounds in newborns?
- preferential listening and sucking rate
- discriminating sounds…suggestive of auditory learning in utero
what is the acoustic environment in utero like for the neonate?
- uterus acts as a 400Hz low pass filter…speech is well transmitted to foetus
- phonetic features of sounds are however not transmitted to the foetus
Fifer and Moon, 1989? how can we infer foetal learning by looking at neonatal preferences
newborns prefer the sound of their mother’s voice over unfamiliar female voices
DeCasper and Fifer, 1980? how can we infer foetal learning by looking at neonatal preferences
measured the sucking response to 25mins of recorded speech 3 days after birth
- each baby was exposed to own mother’s voice and random female voice
- the sucking rates differed between the recordings
…measuring such behaviour can infer foetal learning
Hepper, 1993? inferring foetal learning?
measured ultrasound recordings of foetal movements
@ 36 weeks gestation.
-loudspeaker of own mother’s voice and random female voice to abdomen
-no differences in foetal behaviour exhibited when mother spoke ‘naturally’ (ie when baby was born)
DeCasper and Spence, 1986? neonatal preferences to infer foetal learning
newborns prefer a familiar story read aloud repeatedly during the final weeks of pregnancy than a random novel story they never heard before
Damastra-Wijmenga, 1991? neonatal preferences to infer foetal learning
at 2 days old they paid no attention to sound of lullaby played by mum in utero
…exposed to an alarming noise in utero paid no attention to the same sound after birth, babies not exposed to sound were very startled.
Mehler, 1988? infant auditory preferences
@ 2 days old they preferred the sound of their native language over a non-familiar language
…evidence that newborns extracted prosodic features of sound during the final stages of prenatal development
Cooper and Aslin, 1990? auditory preferences not acquired in utero
newborns from all language backgrounds preferred to listen to infant-directed (motherese) than adult-directed speech
- slow speaking rate
- small no. words
- large pitch excursions
Cooper and Cooper, 1999? auditory preferences not acquired in utero
infants prefer hyper-articulated over normally articulated infant speech
…BUT infant-directed speech is not heard in utero!
neuroimaging and auditory perception
in utero testing:
- MEG/ measures auditory responses in foetus, the magnetic field generated by foetal brain activity passes through the maternal tissues and is detected by MEG externally
- fMRI/ measures spontaneous activity of foetal brain
- NIRS (near infrared spectroscopy)/ optical imaging technique…low levels of light measured in blood flow changes in brain associated with brain activity
Draganova, 2005? MEG testing prenatal sound discrimination
33-36 weeks gestation
sound frequency change detection in foetuses and newborns
Friederici, 2005?
infants brain able to discriminate different phonemes within first 2 mths
12-14mths: lexical-semantic processes
14mths: semantic processing of words and picture contexts