The Cognitive Infant: Pt 1- Visual Cognition

1. The Cognitive Infant:Pt 1- Visual Cognition Early Years Lecture 3

2. Reminder - Tutorial week 1/2 - reading is: Bruner, J. S. & Sherwood, A. V. (1976). Early Rule Structure: The case of "peekaboo". • Reprinted in Gauvain, M. & Cole, M. (1997) (Eds.). Readings on the development of children (2nd edition). New York: Freeman & Co. (see Tutorial Solutions in Library)

3. 3 Theories of Cognitive Development • This lecture - Gibson’s ‘ecological’ theory • Next lecture - Piaget’s ‘constructivist’ theory • Later - Vygotsky’s ‘socio-cultural’ theory

4. This lecture • Outline newborn’s physical state • Methods for assessing cognition?

5. The state of the newborn • Little posture control; muscular limitations • 0 - 6 months; lie prone • 2 months; head control emerging • 6 months; sit upright; crawling • 12 months; walk-like behaviour

6. The state of the newborn • Set of reflexes (e.g.), • knee-jerk (persists into adulthood) • pupil reflex (to light; also permanent) • startle reflex (e.g., to loud noise) • sucking (rhythmic - involuntary) • stepping (disappears after 6-8 weeks) • grasping (spontaneous; for 3-4 months)

7. The state of the newborn • Absence of motor control = other senses important for learning about the world • Vision = most important sense • Q. What does infant visual perception offer in the way of learning?

8. What does the infant know about the world? “one blooming, buzzing confusion” (James, 1890) Two important questions • What do infants know about objects in the environment? • What do infants know about other people?

9. How to measure infant visual perception? • Two dominant experimental techniques Spontaneous visual preference present two stimuli, side by side, measure looking time. Habituation looking declines over time. If discriminating, will look longer at new stimulus.

10. How to measure infant visual perception? • Spontaneous visual preference (Fantz, 1960s) Two visual stimuli left visual fieldright visual field Measure time spent looking L and R stimulus Infants typically spend longer on one Check by counterbalancing stimuli

11. How to measure infant visual perception? • Habituation Present stimulus 1 until infant is no longer interested in it (i.e., is ‘habituated’ to it). Present new stimulus - if infant discriminates > longer looking. Stimulus 1 Stimulus 2

12. How to measure infant visual perception? • Habituation - Pt 2 (Habituation - novelty) Present stimulus 1 until infant is no longer interested in it (i.e., is ‘habituated’ to it). Present old and new stimuli simultaneously. Controls for preference as well as discrimination.

13. How to measure infant visual perception? • Third measure - Heart rate Increased attention = lowering of heart rate Therefore…. Habituation (reduced attention) = higher heart rate Also measures anxiety (but in opposite direction).

14. Object knowledge Do babies perceive the environment as we do? Vision is the least developed sense at birth Retina lacks structure; muscular limits on ability to focus (Banks & Bennett, 1988) • Impoverished visual acuity (Allen, 1978). • Eye movements sluggish (Salivate & Banks, 1978; Aslin, 1981).

15. Development of Object knowledge Pattern perception Infants prefer complex to simple patterns as long as their visual acuity can discriminate between them (Banks & Salapatek, 1983). 1 month > less complex array (8 squares) 2 months > more complex (32 squares) (Fantz & Fagan, 1975)

16. Development of Object knowledge Figure perception 1 month > single feature of figure (e.g., edge) 2 months > central features of figure (Salapatek, 1975) By 2 months, infants developing exploratory behaviour when presented with visual stimuli becoming active in seeking out information.

17. Problem of assessment? Q. How can we assess whether infants are able to make sense of what they see (how to ‘get inside their heads)? e.g., are they able to integrate features of the environment? A. See if they can perceive something that doesn’t actually exist (using habituation method)

18. Development of Object knowledge Boundary perception 4 months > perception of subjective boundaries Ghim (1990) = the search for structure.

19. Development of Object knowledge Habituate to ‘rectangle’..... look longer at triangle

20. Development of Object knowledge • 1 week = patterned > plain shapes • 1 month = single feature > multiple areas = simple > complex • 2 months = scan whole figure = exploratory behaviour • 3 months = complex > simple • 4 months = ‘making sense’ of visual data

21. What about other people? From last week.... ....people = key elements in infant lives > face recognition has ‘adaptive value’

22. Development of People knowledge • Pattern recognition or face recognition? • Newborn preference for face-like pattern (Johnson, 1999) Disappears after 6 weeks A > B

23. Development of People knowledge • Pattern recognition or face recognition? Infants prefer ‘real’ faces to ‘jumbled’ faces. (E.g., Fantz, 1961; Maurer and Barrera, 1981) A > B > C

24. Development of People knowledge • Problems - after 2 months A > C = preference for complexity? A > B = preference for symmetry? A B C

25. Development of People knowledge • Newborn = face-like arrays > inverted faces • 2 months = ‘real’ faces > scrambled faces • 3 months = smiling > frowning faces = attractive > unattractive faces = Mum’s > stranger’s face (Maurer, 1981; Samuels & Ewy, 1985; Barrera & Maurer, 1981)

26. Development of People knowledge • Newborns scan boundaries - but discriminate very simple face-like patterns. • At 2 months explore internal features; able to discriminate realistic from unnatural composition of features. • By 3 months, begin to remember familiar faces and discriminate between different emotions.

27. Developmental theory? • Remember Poincaré’s concern about theory versus facts... ...so far, we’ve discussed the ‘facts’ - the ‘what?’and ‘when?’ issues, but haven’t integrated them into a theory that addresses ‘why?’

28. Getting down to the ‘So what’ • What function (s) - if any - does a developing visual system serve • Obvious! But why a preference for complexity?

29. Why a preference for complexity? What function does it serve? Level of complexity matches the visual acuity of the developing system. Complexity = stimulation. Linear Systems Analysis (Banks & Ginsburg, 1985)

30. Why a preference for complexity? In other words.... ...limitations in the visual system mean that the brain’s processing ability isn’t overwhelmed by too much information... ...visual system constrains cognitive system.

31. What other function? • Complexity ‘drives’ the visual system • Reduction in visual stimulation.....?

32. Why a preference for complexity? Critical period? Kitten experiments. Lack of use = defective vision (Weisel & Hubel, 1963) Impoverished environment > visual impoverishment (Blakemore & Cooper, 1970)

33. Blakemore & Cooper (1970) • Kittens reared in an environment of horizontal or vertical stripes. • Kittens responded to visual stimuli in the familiar orientation, but not in the unfamiliar orientation (e.g. horizontal stripes were ignored by cats reared in the presence of vertical stripes). • Visual cortex neurons - activity only present with stripes in the familiar orientation.

34. A real-world human example? • When are infants aware of the dangers of falling? • Does the visual system recognize these dangers from the outset... ....or do infants learn through experience - the hard way?

35. 2D > 3D Depth perception Visual cliff expts. (Gibson & Walk, 1960) Infants: 6-14 months - central platform 27/27 > shallow side 3/27 > deep side (virtual cliff)

36. Normal vision Reaching - 3 months Crawling - 7 months Walking - 12 months Blind 12 months 13 months 19 months Learning opportunities missed. Delays between 6 - 9 months Impact of visual impoverishment(Levtzion-Korach et al. 2000)

37. Theory of perceptual development • Gibson’s ecological theory Important to ask 4 questions: • What do infants perceive? • How is information processed? • What actions/interactions involved? • What are the consequences of perception? (Gibson & Pick, 2000)

38. Gibson’s ecological theory • Children perceive affordances - opportunities for action/interaction. • Perception = picking up invariant cues from environment. • Third dimension ≠constructed: present at outset. • Development = discovery new affordances. • Linked to motor development.

39. Gibson’s ecological theory: what develops? • Differentiation: the increasing efficiency of the perceptual system and experience allows children to extract information from the environment more accurately (i.e., greater detail) and more efficiently (e.g., discriminating between relevant and irrelevant features)

40. Gibson’s ecological theory: what develops? • Adult Example: New piece of ‘alien’ music (Peking opera; Classical Indian; jazz) Difficult to recognize - but repeated listening reveals the structure that was there all along.. Senses attend to relational info - not static info

41. Gibson’s ecological theory: unbelievers? One of the main objections to Gibson’s theory is that in it, cognition = perception. If perception is ‘direct’, why do infants show interpretation of the perceived environment? If perception = cognition.... what is not perception?

42. Gibson’s ecological theory: unbelievers? As we shall see next time, there is evidence that infants believe that their actions have a causal, rather than a passive, influence on the world, that they impose meaning on what they perceive…. .……enter Jean Piaget.

43. Reading • Berk (1997) - Chap. 4. • Bremner - p.10 - 21 & Chap 3. • Eysenck - p.487 - 496 • Miller - Chap 6 (for Gibson’s theory) • Smith & Cowie - p.251 - 275 Donaldson, M. (1978/1986) Children’s minds. Glasgow: Harper Collins ( highly recommended)