1. Models of Development How do the initial characteristics of the individual and of the environment result in the behavior we see?

2. Typical v. individual development

3. Effects of experience on development of sound encoding Spectral resolution development with normal experience Age Resolution “Quality” (Q 10 ) clicks Spectral resolution development with abnormal experience Age Resolution “Quality” (Q 10 ) baby adult Sanes and Constantine-Paton (1985)

4. Effects of experience on localization by barn owls

5. Reorganization of perception Cue 1 Cue 2 Cue 1 Cue 2 Cue 1 Cue 2 Cue 1 Cue 2

6. Development of cortical EP in children with CI

7. Cellular mechanisms of cortical development: Long-term potentiation LTP is involved in neural plasticity. LTP is eliminated when cochlear input is eliminated. Electrical stimulation of cochlea maintains LTP.

8. People differ, even in perception How do individual differences arise during development?

9. Models of development Genes Genes set limits Gene-environment interaction Gene-environment transaction

10. Genes determine behavior

11. Genes set the limits

12. Genes set the landscape

13. Gene-environment transactions

14. How can experience change genes?

15. Genes make proteins

16. DNA Methylation Differentiation Chromosome inactivation Transcriptional silencing Can be triggered by experience Can be heritable

17. Example: Maternal behavior and stress response

18. “Acquired trait” is heritable

19. Mechanism, Initial biases, Critical period Bad mother demethylates DNA Genes start out methylated: Bias to be outgoing and good mother The effect only occurs between P1 and P6 days Stressed mother  stressed babies – adaptive significance

20. GENES AND ENVIRONMENT CHANGE EACH OTHER conclusion

21. Mother nature counts on experience to guide development

22. Imprinting: Genetic program for behavior?

23. Species-specific call recognition?

24. Gottlieb: Embryonic experience crucial to postnatal social behavior

25. Apparatus for testing postnatal social behavior

26. Gottlieb: Embryonic experience crucial to postnatal social behavior Devocalized duckling approaches chicken call as often as maternal duck call Exposing embryo to embryonic duck call reinstates preference for maternal duck call Exposure to chicken call leads to preference for chicken call* *only in ducklings who had tactile contact with other ducklings

27. Effects of prenatal experience What looks “innate” may result from experience Dependence on experience as economical approach Susceptibility to experience allows for adaptation to environmental conditions

28. Could prenatal sound exposure be important for human development?

29. Newborns prefer speech to sine- wave speech

30. Effect of prenatal exposure to maternal voice

31. Newborns recognize mom’s voice ∆ Interburst interval Infant

32. Newborns’ voice recognition Can discriminate male voices, but don’t prefer dad Prefer low-pass filtered version of mom’s voice over full-spectrum version at birth

33. Do newborns prefer familiar speech? OR Why we can have lots of good fun if you wish, with a game that I call UP UP UP with the fish! ?

34. Newborns prefer familiar speech ExperimentalControl

35. Native language perception by newborns Newborn infants prefer native speech over nonnative Newborns discriminate native v. nonnative across prosodic categories Five-month-olds discriminate native v. nonnative within prosodic category Newborns?

36. Effects of prenatal exposure to speech Newborn infants respond differentially to maternal voice Newborn infants have learned something about the properties of their native speech Long-term effects?

37. Postnatal experience Structure facilitates learning

38. VOT exaggeration

39. Expanded vowel triangle

40. Speech learning and social interaction

41. Speech learning depends on social interaction

42. Conclusions “Transactions” among genotype, epigenotype and experience drive development. Individual differences in any of these factors lead to differences in phenotype. Many of the principles identified in epigenetic studies of nonhumans seem to apply to humans.