Key studies in developmental psychology

Question 1

When does language development start?

Answer 1

• in utero
• Griffiths et al. (1994)
High-quality speech exposure in 3rd trimester

• DeCasper and Spence (1986)
2-3 day old babies prefer rhyme spoken to them
during pregnancy

• DeCasper et al. (1994)
Babies respond in utero to familiar rhyme!

Question 2

How is language development studied in infants

Answer 2

• With such limited repertoires of behaviours and responses in infants, how can we know what they are capable of?
 Systematic observation (Condon & Sander, 1974)
 Preferential looking (familiarization/novelty-preference procedures)
 Physiological measures
 Operant procedures (Fernald, 1985)
 Brain imaging (not covered in this lecture)

Question 3

preferential looking

Answer 3

• Tendency to look at novel things (Fantz, 1963)
• The longer an infant looks at something, the more their attention drifts
 Habituation/familiarization
• If a novel stimulus is presented after one that has been ‘familiarized’ attention will increase once more

Question 4

Preferential looking procedure

Answer 4

• Present stimulus
• Familiarize
• Present original stimulus and novel stimulus together
• If infant can discriminate, then will look at novel stimulus more (‘novelty preference’)
• Used to test discrimination in infants (e.g. Do infants see colour? At what age do they ‘categorise’?)

Question 5

Experimental: categorisation

Answer 5

• Can infants form categories of day-to-day things around them? (Quinn & Eimas, 1996)
• Categorisation can be regarded as one ‘building block’ for language (Quinn & Oates, 2004)
• 3-4 month old infants tested on ability to form the category of ‘cat’

Question 6

Quinn & Eimas (1996)

• Familiarization phase:

Answer 6

 Shown pictures of different domestic cats in different postures

Question 7

Quinn & Eimas (1996) testing phase

Answer 7

 Shown novel cat (in novel posture) alongside dog

 What will the infants do?

Question 8

Quinn & Eimas (1996) results

Answer 8

• On average, they spend longer looking at the dog
 NB both ‘cat’ and ‘dog’ picture were new
 Looking longer at the ‘dog’ indicates that the category of cat had become familiar

• To the infant, the dog is more ‘novel’ than the cat
• But they have seen neither this cat nor this dog before
• Therefore, the familiarity of the cat must be something to do with its category membership

Question 9

Physiological measures — DeCasper et al. (1994)

Answer 9

 Mothers in 35th week recited rhyme to babies 3 times per day for 4 weeks
 After 4 weeks rhymes were played to mother’s abdomen while monitoring baby’s heart rate
 Mothers listened to something else

Question 10

DeCasper et al. (1994) results

Answer 10

Significant decrease in heart rate for familiar rhyme (no change for unfamiliar)
• Something about the rhyme (not the reader, nor just ‘sound’) was already familiar to baby in utero.
• Infant does something to cause a stimulus to be played/displayed
 e.g. sucking on a dummy sensor

Question 11

DeCasper & Spence (1986) (different experiment)

Answer 11

mothers read cat in the hat twice a day for six weeks before due date
 Babies split into 2 groups, baselined on sucking
 Group A heard cat in the hat when they sucked
 Group B heard a different story
 Group A showed higher rates of sucking, even when story read by different person

Question 12

Brain imaging: PET

Answer 12

 Injection of radioactively labelled substance

Question 13

Brain imaging: ERPs

Answer 13

 Electrical activity measured through scalp

Question 14

Brain Imaging: FMRIs

Answer 14

 Non-invasive measurement of cerebral blood flow