1. Infants Preconditioned Memories and Deferred Imitation

• David A. Townsend and Carolyn Rovee-Collier

Early Learning Project

Department of Psychology

Program in Biopsychology & Behavioral Neuroscience

Rutgers University, Piscataway

2. 2, 3,6,9, 12, 15, & 18 months 3. Transitivity

A = B, B = CTherefore: A = C

Amy > Kim

Kim > Vivian

Therefore:

Amy > Vivian

Of or relating to a relationship between three elements such that if the relationship holds between the first and second elements and between the second and third elements, it necessarily holds between the first and third elements. Examples of transitive relationships are equality for numbers and divisibility for integers .TheTransitivityof Preconditioned Infantile Memories During Deferred Imitation(Townsend, 2006; Townsend, et al. 2008) 4. The Problem:

A lack in the infant literature on infants ability to form associations.

Traditionally, developmental experts insist imitation and the underlying representational abilities do not emerge until 18 months of age (Anisfeld, 2005; Piaget, 1962).

It is still widely believed that infants are not physiologically capable of formingenduring memories of one-time events (McKee & Squire, 1993; Nelson, 1995), much less associate their representations .

SO

In the absence ofexplicit reinforcement; how do infants pick up information from their environment, how do they represent it, and how do they integrate it - - if they do?

5. The Problem

In the absence of explicit reinforcement, can infants pick up information from their environment and integrate it over sessions

Can infants form multiple associations between pairs of stimuli that they encounter over successive days during the preexposure phase of a sensory preconditioning procedure?

Can they integrate these multiple associations?

If so, how are these associations represented?

First, the tasks

6. Sensory Preconditioning Procedure (SPC) Two stimuli become associated even though both are weak.CS2 CS1 CS1 US CR1 CS2 CR1 Because both stimuli are neutral in the first stage,there is no robust response to measure. Phase 1 Phase 2 Phase 3 The Transitivity ofPreconditionedInfantile Memories During Deferred Imitation SENSORY PRECONDITIONING (SPC) paradigm: an association is formed between two neutral stimuli without either explicit reinforcement or an overt response.Phase 1,two neutral stimuli (S1, S2) are paired.Phase 2,subjects learn a specific response (R1) to one of the stimuli (S1) .In Phase 3 , subjects are tested with the other stimulus (S2).If they produce the learned response(R1)toS2 , then this indicates that an association had been formed betweenS1 and S2 in Phase 1. 7. Deferred Imitation:

Demonstration:

model a sequence of three target actions

24-h imitation test:

1) remove the mitten

2) shake the mitten

3) attempt to replace the mitten

The Transitivity of Preconditioned Infantile Memories DuringDeferred Imitation 8. Deferred Imitation: Training procedure in which subjects are given the opportunity to reproduce a modeled behavior after a delay

Demonstration:

model a sequence of three target actions

24-h imitation test:

1) remove the mitten 2) shake the mitten 3) attempt to replace the mitten

Apparatus:hand puppet

• • with a removable felt mitten in a matching color

Trip 9. 10. Puppet Stimuli 11. A/B Phase 1 Phase 1 Phase 2 Phase 3 A/B B- ModeledA- Imitation 12. B Demonstration Phase 2 Phase 1 Phase 2 Phase 3 A/BB- Modeled A- Imitation 13. A Imitation Test Phase 3 Phase 1 Phase 2 Phase 3 A/BB- ModeledA- Imitation 14. Sensory Preconditioning Procedure Two stimuli become associated even though both are weakA B B R1 (modeled) A R1 (imitation) Because both stimuli are neutral in the first stage,there is no robust response to measure. Phase 1 Phase 2 Phase 3 Phase 1 / SENSORY PRECONDITIONING (SPC) paradigm: an association is formed between two neutral stimuli without either explicit reinforcement or an overt response.Phase 1,two neutral stimuli (S1, S2) are paired.Phase 2,subjects learn a specific response (R1) to one of the stimuli (S1) .In Phase 3 , subjects are tested with the other stimulus (S2).If they produce the learned response(R1)toS2 , then this indicates that an association had been formed betweenS1 and S2 in Phase 1. 15.

6-month-olds can exhibitsignificantdeferred imitation of the target actions on the puppet for only 1 day

6-month-olds do notspontaneously perform the target behaviors

6-month-olds do not spontaneouslygeneralize modeled behaviors across puppets

Deferred Imitation at 6 months: 16. S1-S2 Preexposure( Phase 1) 17. Model Actions on S1(Phase 2) 18. Imitation Test (Phase 3) Emma 19. Another test example 20. The Problem:

A lack in the infant literature on infants ability to form associations.

Traditionally, developmental experts insist imitation and the underlying representational abilities do not emerge until 18 months of age (Anisfeld, 2005; Piaget, 1962).

It is still widely believed that infants are not physiologically capable of formingenduring memories of one-time events (McKee & Squire, 1993; Nelson, 1995), much less associate their representations .

SO

In the absence ofexplicit reinforcement; how do infants pick up information from their environment, how do they represent it, and how do they integrate it - - if they do?

21. Methods

Participants . 97, 6-month-old infants. (Girlsn =45)

Apparatus. Stimuli were drawn from a pool of 6 puppets that were not commercially available.

Procedure.

Phase 1(Preexposure): Experimental groups were simultaneously preexposed for 1 hr to puppets.

Phase 2(Demonstration)

Phase 3(Deferred Imitation Test)

Analysis.

An infants imitation score was the total number of actions (range, 0-3) copied. A pooled baseline control group ( N= 45) that did not see the demonstration provided the base rate at which infants spontaneously produce the target actions.(The test session was their only session). (Deferred Imitation )

ANOVAs of experimental groups. ( Training )

22. Sensory Preconditioning Procedure Two stimuli become associated even though both are weakA B B R1 (modeled) A R1 (imitation) Because both stimuli are neutral in the first stage,there is no robust response to measure. Phase 1 Phase 2 Phase 3 Phase 1 / C B A/B (1h-day) Generalization B A No Preexposure A B A (30m) B (30m) A/B Unpaired Group A B A/B (1h-day) Experimental Group Phase 3 Imitation test Phase 2 Demonstration of target actions Phase 1 Preexposure (2 days) 23. Experimental Design A B Puppet A(30 min AM) Puppet B(30 min PM) ControlGroup (Unpaired) AB Puppets A/B (1 hr/day) Experimental Group (Paired) Phase 3 Imitation Test Phase 2 Demonstration of Target Actions Phase 1 Preexposure (2 days) 24. Rovee-Collier, C. et al.,(2003). 25. Can infants could form an association between each of 2 pairs of puppets? Transitivity? A C B B/C A/B ExtC/AA B B A/B B/AA C B/C A (30m) B (30m) C/A Unpaired A C B/C A/B C/A pairedPhase 3 Test Phase 2 Demonstration Extinction (afternoon session 2) Phase 1 Session 2 Phase 1 Session 1 Group: 26. Results: 27. Puppet A C association How are A and C associated? Direct A to C association?BC = memory AB =duringPhase 1, A/C (Perceptual Learning: Hall, 1996; SOP: Wagner, 1981) Compounding?AB = BC = at test A= AB and BC (Dissociation: Rescorla,1981) Chain of associations?AB, BC = A-B-C A link of associations mediated by B A C B/ C A /B C/A paired Phase 3 Test Phase 2 Demonstration Phase 1 Session 2 Phase 1 Session 1 Group: 28. Do babies have implicit or explicit memory? 29.

Experiment 2 asked if an additional association (puppets C-D) could be added to the prior associative chain.

we asked if exposing infants to more puppet exemplars in Phase 1 would reduce the specificity of imitation.To answer this, we tested group D/E with a novel puppet.

Experiment 2 30. Infants can form multiple associations between stimuli that they merely see together E D C/D B/C A/B D/E A D C/D B/C A/B D/A Phase 3 Test Phase 2 Demonstration Phase 1Session 3 Phase 1 Session 2 Phase 1 Session 1 Group: 31. Experiment 2

These results demonstrate that :

infants can form multiple associations between stimuli that they merely see together; there was no evidence of retroactive interference.

the multiple associations remained specific, despite the large number of puppets that were exposed.

32. Forward and Backward Forward: At test (A) to get to (C)A - B - C Backward: At test (C) to get to (A)C - B - A A C B/C A/B C/APhase 3 Test Phase 2 Demonstration B alone (afternoon session 2) Phase 1 Session 2 Phase 1 Session 1 Group: C A B/C A/B A/CPhase 3 Test Phase 2 Demonstration B alone (afternoon session 2) Phase 1 Session 2 Phase 1 Session 1 Group: 33. Experiment 3

We asked if the associative chains between puppets A and C were bidirectional.To answer this, we demonstrated the target actions on puppet A and tested infants with puppet C (group A/C).

Infants received anextinction procedurewith puppet B after the demonstration on puppet C to observe if the prior associative chain is affected by the new information updated during the demonstration (group Aext/C, Cext/A) and if an associative chain is retrieved during Phase 3.

A control group (group ExtC/C) was included to ensure that exposure to a single puppet after Phase 2 does not disrupt infants ability to imitate 24 hr after training.

34. Results Equivalent? 35. Latency to perform the 1 sttarget action Increased latency to perform a response can indicate that a task is more difficult (Bjork, 1988)Harder to retrieve memories may be strengthened more and subsequentlyremembered longer Townsend (2006) Schmidt & Bjork (1992) Anderson, Bjork & Bjork (1994) Vander Linde, Morrongiello, & Rovee-Collier, (1985) 36. Transitivity?

1If A = B and B = C, then A = C.

2)If A = B, B = C, and C = D, then A = D.

Transitivity involvingidentity relationsmay be the earliest form of relational learning to appear in development.Its neuralbasis is unknown.

a relationship between three elements such that if the relationship holds between the first and second elements and between the second and third elements, then it necessarily holds between the first and third elements. 37. Implications

A = B, B = C,Therefore: A = C (puppets)

According to Smith and Squire (2005), transitivity among elements in an associative chain is a marker of a higher-level declarative memory system.

Deferred imitation isalso considereda marker of declarative memory.

These data add to a growing body of research suggesting that preverbal infants are capable of forming, complex, transitive associationsdeclarative memory?

A = B, B = C,Therefore: A = C 38. Applied: Dunst et al. 2006 39. The Transitivity of Preconditioned Infantile Memories During Deferred Imitation

Carolyn Rovee-Collier(Rutgers University)

Rachel Barr(Georgetown University)

Amy Learmonth

(Manhattenville College)

Early Learning Project: Amy Bullman Kimberly Cuevas Dr. Kelly DiGian Jen Gomberg Amanda Hamilton Erika Hussey Dr. Vivian Hsu Megan Kuhn-McKearin Christiana Shafer 40. David and the Baby Lab Cognitive development may not be as universally stage-like as Piaget suggested Early Learning Project: Amy Bullman ( M.S.) Jen Gomberg Amanda Hamilton Erika Hussey ( Maryland ) Dr. Vivian Hsu ( Ph.D.) Megan Kuhn-McKearin ( NYU ) 41. Questions?