Lecture 1 - Infant capabilities

• Nature/nurture debate


  How innate is human development? nativist vs behaviourist (how much is acquired from the environment)
• Infants can understand the concept of gravity, recognise sounds from the womb, distinguish between speech sounds
• William James (empiricist)


  Babies are confused as their senses are overloaded at once. Did not have the right methods or measures to explore this.
• What can infants do?

  • Look
  • Turn their heads
  • Reflexes (moro reflex, sucking, crying)
  • Get bored
• Experimental techniques for testing infants

  • Eye tracking
  • Physiological measures (EEG, ECG)
  • Preferential sucking
  • Looking time methods
• Looking time methods


  • Spontaneous visual preference
  • Habituation
  • Violation of expectation
• Spontaneous visual preference


  Gauge whether baby is drawn more to one stimulus than another
• Habituation


  Process in which attention to novelty decreases with exposure
• Violation of expectation


  When an infant shows 'surprise', evidence for violation of expectation
• Babies can recognise different primate faces (eg two different lemurs) whereas adults and infants cannot. This is due to synaptic pruning & perceptual narrowing where irrelevant/non useful connections are lost to specialise us in dealing with human beings.
• Habituation as a diagnostic tool

  1. Early habituation speed predicts later IQ

  2. Visual recognition memory predicts IQ at age 11
• Violation of expectation method

  Tells us that the infant doesn't understand the concept of object permanence - once an object disappears out of their eyeline, it's as if it no longer exists
• Violation of expectation method

  • Magic trick (tissue disappears from hand)
  • Baillargeon's support relations (ball staying suspended when rolling off)
  • Kim and Spelke (ball rolling down and up the hill)
• Baillargeon's drawbridge task


  Infants familiarised with flap going up and down, then shown 'possible' and 'impossible' events. From 3.5 months, infants looked more at impossible events, suggesting they understand object permanence
• High Amplitude Sucking (HAS)


  Sucking is an innate reflex and can vary the RATE and PRESSURE of sucking
• Habituation procedures


  Baby given pacifier connected to transducer (measures rate and strength of sucking), when baby sucks hard on dummy, they get to hear a stimulus - indicates interest/preference for a stimulus
• Eimas et al (1971) - 2 month olds can discriminate phonemes eg. [p] in pat and [b] in bat
• Newborns prefer their mothers voice, Newborns remember stories heard in the womb