Cognitive Development

1. Cognitive Development

2. Food for thought • Do babies have “naïve concepts” – that is, do that have some sense of physics, math, etc. from birth? • How can you tell what a baby knows? • How can you tell what a baby remembers?

3. Spatial Cognition • How do we know/remember where things are? • How do we find our way around in the world? • How is our brain involved in where we direct attention?

4. Dorsal/ventral pathway • From visual cortex through parietal lobes into prefrontal cortex. • Dorsal pathway areas in visual cortex receive input from cells in the retina/thalamic pathway that are sensitive to movement and peripheral stimuli • “Where” pathway

6. Searching tasks • AB error A B

7. Searching tasks • AB error A B

8. Searching tasks • AB error A B

9. Searching tasks • AB error A B

10. What does the AB task involve? • Memory for location – originally thought to be a memory task • Systematic changes in the length of delay required to get the AB error. • Implicates areas other than memory areas • Inhibition • Experience has an effect • Infants who walk are less likely to make the AB error • Healthy premature infants outperform term infants of the same conceptual age

11. DLPFC

12. Spatial Attention • Right hemisphere – Global attention • Left Hemisphere – Local attention

13. S S S S S S S S S S S S S S T

14. Brain basis of spatial attention • Children are less lateralized than adults • Children with lesions recover function • Recovery is very slow • Processing is not always typical • These differences are apparent in other tasks (e.g., block construction).

16. Number processing • Infants attend differentially as if they understand number concepts

18. Number processing • Infants attend differentially as if they understand number concepts • Infants have a non-linguistic “counting” mechanisms

19. Systems for number representation • Object-file representations • Infants visually track objects and their properties, including number • Quantity is limited (up to 4 objects) • Object representations are affected by inferior parietal damage in adults • Activity in these areas is observed when people do object processing tasks

20. Analog-magnitude representation • Number is represented not as an absolute integer based on its magnitude • Also likely to involve inferior parietal cortex • Unclear whether it’s the same part of inferior parietal cortex

21. Integer lists • Later developing • One to one correspondence between number word and object • Probably involves inferior parietal cortex, as well and language areas

24. (More) food for thought • Can infants form memories? • What do infant memories look like? • If infants can form memories, why don’t adults remember things that happened to them when they were infants?

25. Memory • Explicit vs. implicit memory • Explicit memory • Able to talk about/describe what you remember • Characteristics of explicit memory • Fast • Flexible • Fallible • Implicit Memory • Not explicit

26. Brain systems • Explicit Memory • Medial Temporal Lobe • Hippocampus • Surrounding cortex • Medial thalamus • Cortex • Prefrontal • Association networks

30. Neural Circuit for Explicit Memory • Frontal Cortex and Temporal Pole • Matures late • Involved in retrieval from long-term memory and memory for temporal order • Medial diencephalon • Matures early • Involved in integration of information across modalities • Medial Temporal Lobe • Matures early • Involved in encoding and consolidation of new memories • Cortical Association Areas • Mature late • Involved in storage of representations

31. Implicit Memory • Basal ganglia, Caudate, Putamen (skilled learning) • Hippocampus, cerebellum (conditioning) • Perceptual areas (priming) • Most areas and functions mature early in development

32. Development of explicit memory • Early developing components of system • Medial temporal lobe • Habituation, novelty preference • Thalamus • Integration of information • Later developing components • Association cortex • Prefrontal cortex

33. How do you study explicit memory in nonverbal infants? • Imitation tasks • Infants can remember some aspects of events as early as 6 months of age • Infants remember events for long periods of time only at the end of the first year of life • 9 month olds remember for 1 month • 10 month-olds may remember for up to 6 months • Changes in this ability are related to changes in brain development

37. About 50% of nine-month-olds recall events after 1 month • ERPs show that the same infants recognize pictures of the props used to enact these events

38. Memory development after infancy • Strategies • Rehearsal • Chunking • Source memory • Knowing where and when you learned information • Both strategy and source memory likely depend on maturation of frontal areas • Develop gradually over childhood

39. Later memory development • Source memory • Children begin to perform at adult-like levels in tasks of source memory by about age 6 • Likely involves frontal lobe areas that in adults are involved in source memory

40. Metamemory • Knowing what you know • Using strategies to improve your performance • Some lesion studies in adults suggest that frontal lobe damage impairs metamemory • Ventral medial prefrontal • Other research suggests that this depends on the nature of the task • Very little has been done about the brain basis of metamemory • Some behavioral research suggests that children start using strategies somewhere around age 6. • Not clear whether this is related to other memory development (e.g. source memory) that occur around this same time. • Likely continues through adolescence

41. Development of Implicit Memory • Procedural learning • Infants as young as 4 – 5 months can do some version of serial reaction time tasks • There is a gradual increase through at least childhood in speed of learning and accuracy • May involve motor as well as memory development

42. Conditioning • Infants can be conditioned from very early in life • Example: Contingent response paradigms • Suggests that the hippocampal – brainstem – cerebellum circuit is mature early in development • Some components of this implicit system are shared with the explicit system • So there is likely overlap in systems used for different tasks

43. Priming • Some evidence that infants can be primed • ERP study: Infants shown repeating or non-repeating stimuli • Infants brain activity is different for repeated than for unrepeated stimuli • Is this priming or recognition???

44. Categorization • Ability to understand that similar things belong in the same category • Sequential touching tasks • Develops in the second and third year of life

45. Generalization and analogy • Ability to apply information from one setting into another • Example: Imitation tasks • Can infants use different props to complete the same event? • Can infants solve problems with new tools, if they’ve been shown how with old tools

48. Generalization and analogy • Brain systems for categorization, analogy, and generalization are unknown, but likely involve frontal areas • Development is gradual • Analogy can be seen in preschoolers, full development occurs over childhood