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
Dehaene-Lambert, 2002? speech perc emerges before speech production
fMRI of 2-3mths, when listening to speech there were left-lateralised responses in superior temporal gyrus and angular gyrus
…superior temporal gyrus (STG) selectively responds to forward speech (Wernicke’s area before Broca’s area forms….I understand as babies can understand what you’re saying first and then they develop the ability to actually speak
Silbo and Gomero? specificity of speech perception at birth
used NIRS to measure brain activations to speech in newborns
greater activation to speech than non-speech
May and Gervain, 2015? understanding native lang
familiar (english) and non-familiar (german) activated anterior brain regions associated with speech perception
Kuhl, 2008? discriminating sounds pertaining to native lang
7mths old were able to discriminate between sounds in native but not sounds in non-native lang
…evidential of ‘perceptual narrowing’
Imada and Zhang, 2006? speech perc and production
link between auditory and speech production areas
43 infants exposed to pure tones, harmonics and syllables
- activation of STG area/Wernicke’s area=speech perception
-6mths + 1yr, speech stimuli activated Broca’s area (speech production) and motor areas simultaneously
…evidence of ‘cross-talk’ between areas that produce speech
Imada and Zhang, 2006? wernickes and brocas
W’s area has less activation as the baby develops (perceptual narrowing)
B’s area becomes more activated with development
Mampe, 2009? cry melody shaped by native lang
analysed crying patterns from 30 french and 30 german babies
-melody and intensity contours
…contours were specific to each language…influence of surrounding speech prosody on newborn’s melody cry
Green and Gustafson, 1983? recognising own baby’s cry
individual recognition of infant based on their cries
80% of mothers and 45% of fathers were able to identify their own child’s cry based on their acoustic cues
Sander, 2007? brain responses to infant sounds
nonparental men and women, on the pure tone detection task; listened to laughing/crying infants
- infant sounds elicited a stronger activation of amygdala and anterior cingulate cortex in women
- control stimuli elicited a stronger activation in men
- reflects neural predispositions
Seifritz, 2003? brain responses influenced by sex/experience?
-females (independent of parental status): neural deactivation of anterior cingulate cortex for both laughing and crying
-parents vs. non-parents (independent of sex): amygdala of parents elicited a stronger activation from crying; non-parents had stronger activation to infants laughing
…may show an adaptive mechanism, critical in bonding mechanisms for offspring wellbeing and survival.
