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Senior seminar 08
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
3. Transitivity
The Transitivity of Preconditioned Infantile
Memories During Deferred Imitation
(Townsend, 2006; Townsend, et al. 2008)
• A = B, B = C Therefore: 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.
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 forming enduring memories of one-time events (McKee & Squire,
1993; Nelson, 1995), much less associate their representations .
SO…
• In the absence of explicit 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.
Phase 1 Phase 2 Phase 3
CS2 CS1 CS1 US CS2
CR1 CR1
SENSORY PRECONDITIONING (SPC)
paradigm:
an association is formed between two neutral
Because both stimuli are
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).
neutral in the first stage,
In Phase 3, subjects are tested with the other
stimulus (S2). If they produce the learned
response (R1) to S2, then this indicates
there is no robust response to
that an association had been formed
between S1 and S2 in Phase 1. measure.
The Transitivity of Preconditioned Infantile Memories During Deferred Imitation
7. The Transitivity of Preconditioned Infantile Memories During Deferred Imitation
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
8. Deferred Imitation: Training procedure in which
subjects are given the opportunity to reproduce a modeled behavior after a
delay
Demonstration:
• model a sequence
Trip of three target
actions
• 24-h imitation test:
1) remove the mitten
2) shake the mitten
Apparatus: hand puppet 3) attempt to replace
with a removable the mitten
felt mitten in a
matching color
13. A – Imitation Test Phase 3
Phase 1 Phase 2 Phase 3
A/B B- Modeled A- Imitation
14. Sensory Preconditioning Procedure
Two stimuli become associated even though both are weak
Phase 1 Phase 2 Phase 3
A / B B A
R1 (modeled) R1 (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. Because both stimuli
Phase 2, subjects learn a specific response (R1) to
one of the stimuli (S1).
In Phase 3, subjects are tested with the other
are neutral in the
first stage,
stimulus (S2). If they produce the learned
response (R1) to S2, then this indicates
that an association had been formed
between S1 and S2 in Phase 1.
there is no robust
response to measure.
15. Deferred Imitation at 6 months:
• 6-month-olds can exhibit significant
deferred imitation of the target actions on
the puppet for only 1 day
• 6-month-olds do not spontaneously
perform the target behaviors
• 6-month-olds do not spontaneously
generalize modeled behaviors across
puppets
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 forming enduring memories of one-time events (McKee & Squire,
1993; Nelson, 1995), much less associate their representations .
SO…
• In the absence of explicit 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. (Girls n=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 infant’s 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)
22. Sensory Preconditioning Procedure
Two stimuli become associated even though both are weak
Phase 1 Phase 2 Phase 3
A / B B A
R1 (modeled) R1 (imitation)
Phase 1 Phase 2 Phase 3
Preexposure Demonstration Imitation
(2 days) of target actions test
Because both stimuli Experimental
A/B
(1h-day)
B A
are neutral in the first
Group
A/B A (30m) B A
Unpaired B (30m)
stage, Group
No A B
there is no robust
Preexposure
Generalization A/B B C
(1h-day)
response to measure.
23. Experimental Design
Phase 1 Phase 2 Phase 3
Preexposure Demonstration Imitation
(2 days) of Target Actions Test
Experimental Puppets A/B B A
Group (1 hr/day)
(Paired)
Control Group Puppet A
(Unpaired) (30 min AM) B A
Puppet B
(30 min PM)
24. 3.0
Exp. 1a Exp. 1b
Imitation Score
2.0
* *
1.0
0.0 baseline
Paired/B Unpaired/B Paired/C x/B Paired/B 2-
day
Preexposure/ Test Group
Rovee-Collier, C. et al., (2003).
25. Can infants could form an association
between each of 2 pairs of puppets?
Group: Phase 1 Phase 1 Extinction Phase 2 Phase 3
Session 1 Session 2 (afternoon session 2) Demonstration Test
C/A paired A/B B/C C A
C/A Unpaired A (30m) B/C C A
B (30m)
B/A A/B B B A
ExtC/A A/B B/C B C A
Transitivity?
27. Puppet A – C association
Group: Phase 1 Phase 1 Phase 2 Phase 3
Session 1 Session 2 Demonstration Test
C/A paired A/B B/C C A
How are A and C associated?
Direct A to C association? BC = memory AB =
during Phase 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
29. Experiment 2
• 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.
30. Infants can form multiple associations between
stimuli that they merely see together
Phase 1 Phase 1 Phase 1 Phase 2 Phase 3
Group: Session 1 Session 2 Session 3 Demonstration Test
D/A A/B B/C C/D D A
D/E A/B B/C C/D D E
31. Experiment 2
These results demonstrate that :
Experiment 2
• infants can form multiple 2.0
*
associations between stimuli 1.5 *
Imitation Score
that they merely see together; 1.0
there was no evidence of
Baseline
Control
0.5
retroactive interference. 0.0
C/A D/A D/E
Demo/Test Group
• the multiple associations
remained specific, despite the
large number of puppets that
were exposed.
32. Forward and Backward
Group: Phase 1 Phase 1 B alone Phase 2 Phase 3
Session 1 Session 2 (afternoon session 2) Demonstration Test
C/A A/B B/C C A
Forward: At test (A) to get to (C) A-B-C
Backward: At test (C) to get to (A) C - B - A
Group: Phase 1 Phase 1 B alone Phase 2 Phase 3
Session 1 Session 2 (afternoon session 2) Demonstration Test
A/C A/B B/C A C
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 an extinction procedure with
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.
35. Latency to perform the 1st target action
100
Increased latency to *
perform a response can 80
indicate that a task is more
difficult (Bjork, 1988) 60
Latency (s) 40
Harder to retrieve memories may
be 20
strengthened more and
subsequently 0
C/A D/A A/C
Demo/Test Group
remembered 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 involving identity relations may be the
earliest form of relational learning to appear in
development. Its neural basis 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
• 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 is also considered a
marker of declarative memory.
• These data add to a growing body of
research suggesting that preverbal
infants are capable of forming, complex,
transitive associations…declarative
memory?
39. The Transitivity of Preconditioned Infantile
Memories During Deferred Imitation
• Carolyn Rovee- Early Learning Project:
Amy Bullman
Collier (Rutgers University)
Kimberly Cuevas
• Rachel Barr
(Georgetown University) Dr. Kelly DiGian
Jen Gomberg
• Amy Learmonth Amanda Hamilton
• (Manhattenville College)
Erika Hussey
Dr. Vivian Hsu
Megan Kuhn-McKearin
Christiana Shafer
40. David and the Baby Lab
Early Learning
Project:
Amy Bullman (M.S.)
Jen Gomberg
Amanda Hamilton
Erika Hussey
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture. (Maryland)
Dr. Vivian Hsu
(Ph.D.)
Megan Kuhn-
McKearin (NYU)
“Cognitive development may not be as
universally stage-like as Piaget suggested”
Thank you Carolyn for that ________ Introduction. Today I will be presenting data on the associative capabilities of 6 month old human infants. I though a good way to start would be to explain my title.
Transitivity refers to the logical relationships among stimuli, even if some of those stimuli have never appeared together. On the basis of the orderly relationships you have observed directly, you can INFER the logical relationship between two stimuli you have not. The definition at the bottom of this slide is rather involved, but we use transitive inference all the time. A simple example involves height. If Amy is taller than Kim, and Kim is taller than Vivian, then we can use the information we have to infer that Amy is taller than Vivian.
THERE IS NO BACKGROPUND ON IT IN THE INFANT LITERATURE BECAUSE MOST PEOPLE HAVE JUST BARELYACCEPTED T HAT 6-MO-OLDS CAN IMITATE AFTER 24 HR—AND EVEN THAT HAS BEEN DISMISSED BY THE “USUAL” ANTAGONISTS AND PIAGETIANS, WHO THINK IMITATION IS IMPOSSIBLE BEFORE 18 MONTHS OF AGE. SO, INSTEAD OF SHOWIG 1 PAIR FOR 1 DAY, YOU WILL SHOW A DIFFERENTPAIREACH DAY WITH A COMON MEMBER FROM ONE DAYTO THE NEXT. YKJU ARE ASKING HOW INFANTS REPRESENT INFORMATION THAT THEY MERELY PICK UP AND HOW, IF THEY DO, TO THEY INTEGRATE
The term preconditioning in the title of this presentation refers to the experimental procedure that was used in the four experiments I am going to discuss today . association mediated the transfer of the CR from CS1 to theCS2 SPC involves 3 phases. In the first phase two stimuli are paired. The Phase 1 stimuli are neutral, meaning that they do not usually have biological relevance or produce responding in themselves (Except an orienting response). In Phase 2 of the SPC procedure, one of the stimuli (CS1) is paired with an outcome, a US, so that it will elicit a conditioned response (CR1) after training. . In Phase 3, the other neutral stimulus, or CS, is presented alone. Responding to this stimulus is taken as evidence that an association was formed between the Phase 1 stimuli, without explicit reinforcement and this association mediated the transfer of the CR from CS1 to theCS2. The Phase 1 association is referred to as BehavioralLY Silent, since it cannot be observed and, without the other two Phases of the SPC procedure, it could never even be inferred to exist .
So moving on with the title of this presentation, I am going to spend some time discussing Deferred Imitation. Deferred Imitation is a procedure in which an adult models a series of target actions on an object—here, a hand puppet—and subjects are given an opportunity to reproduce the modeled behavior after a delay. Barr, Dowden, and Hayne Demonstration 24h Test It was long believed that the brain of infants less than 8-9 months of age was functionally too immature to permit deferred imitation. However, In 1996, Barr, Dowden, and Hayne developed the puppet imitation task and dispelled this belief. In their task, the experimenter demonstrates three target actions on a hand puppet: 1) remove the mitte n from the puppet's hand, 2) shake it three times to ring a jingle bell pinned inside, 3) replace the mitten . This sequence takes 10 s and is shown 6 times for a total of 60 s to yield 24-hr imitation at 6 months; During the deferred imitation test, the infant’s imitation score is the total number of target actions (range 0-3) that he or she reproduces within 120 s of first touching the puppet. This slide shows an imitation test with a 6-month-old. He has removed the felt mitten on the puppet’s right hand.
So moving on with the title of this presentation, I am going to spend some time discussing Deferred Imitation. As you can see, Deferred Imitations a Training procedure in which subjects are given the opportunity to reproduce a modeled behavior after a delay. It was long believed that the brain of infants less than 8-9 months was functionally too immature to permit deferred imitation. However, In 1996, Barr and Hayne developed the puppet imitation task and dispelled this belief. During the demonstration, the experimenter demonstrates three target actions on the a hand puppet: 1) remove the mitte n from the puppet's hand, 2) shake it three times to ring a jingle bell pinned inside, 3) replace the mitten . This sequence takes 10 s and was shown 6 times for a total of 60 s. During the test, 24 for hours after the demonstration, the infant is given an opportunity to imitate the modeled actions. His imitation score is the number of target actions (range 0-3) that he reproduces within 120 s of touching the puppet. This is an imitation test with a 6-month-old. He is reaching for the felt mitten on the puppet’s right hand.
The top picture here shows the six different puppets that were used in the experiments I am going to be presenting today. Puppets were counterbalanced within groups. The picture at the bottom shows another 6 month old infant removing the mitten during the imitation test. AND..
Specifically, In Phase 1 of our SPC procedure, 6-month-old infants are preexposed to puppet pairs for 1 hour. The puppets were placed out of infants’ reach during a free play time. In this picture here two puppets were displayed side by side in the infants full view, but out of reach, for a preexposure session of 1 hour Additionally, Barr and colleagues subsequently found by measuring how long infants actually fixate on the stimuli, that relatively little attention was required for infants to form associations between puppets (Barr et al., 2003).
This is a video of the target behaviors being modeled that Tripp Richter was gracious enough to participate in these studies. You can see the three behaviors that are modeled for infant… Removing the mitten Shaking the mitten and replacing the mitten I would like to point out the at 6 months of age infants very rarely replace the mitten during the imitation test .
In phase 3 we measure whether the target actions have transferred to the other Phase 1 puppet. This is an infant during Phase 3, or the imitation test of the procedure used in the present experiments. 6-month-old infants have 120s after they first touch the puppet to imitate any of the target actions. So during our SPC procedure, during phase 1 infants are exposed to puppets, In phase 2, the target actions are modeled on one of the preexposed puppets.. In phase 3 we measure whether the target actions have transferred to the other Phase 1 puppet.
Previously, we adapted the SPC procedure for the puppet imitation task by simultaneously exposing infants to a pair of puppets, A and B, before the demonstration and then “training” a response to one of the puppets (Puppet B) by modeling the target actions on one puppet of the pair. In the final phase, we tested infants for deferred imitation with the other puppet. This procedure exploited the fact that infants do not spontaneously generalize the modeled actions to a puppet other than the one on which the actions were originally demonstrated. If the infant imitated the actions on the other puppet, then we assumed that an association had been formed between the paired puppets in phase 1 and that this association mediated the transfer of responding from puppet B to puppet A.
indicating that each of the puppets used in the following experiments is treated as a unique stimulus or event . All the subjects in the present studies were 6-month-old human infants. At 6 months infants are nonverbal and are about one or two months crawling. So at this age, infants learn much about their environment through passive observation. Six month olds do not spontaneously perform the target behaviors on a puppet even if it is familiar if they have never seen them modeled Nor during testing do they generalize the modeled behaviors across these same puppets (Hayne et al., 2003a) before 18 months of age, indicating that each of the puppets used in the following experiments is treated as a unique stimulus or event. Because infants can only successfully imitate the target actions if they remember having seen them on a single, prior occasion, deferred imitation is widely regarded as a declarative memory task (Bauer 1996).
Explicit and implicit memory emerge at different rates and involve different parts of the brain. Earliest memories seem to be implicit, and they involve the cerebellum and brain stem. The forerunner of explicit memory involves the hippocampus, but true explicit memory doesn’t emerge until the second half of the first year. When explicit memory does emerge, it involves an increasing number of areas of the cortex of the brain (Vargha-Khadem et al., 1997; Bauer et al., 2003; Bauer, 2004; Squire & Knowlton, 2005). THERE IS NO BACKGROPUND ON IT IN THE INFANT LITERATURE BECAUSE MOST PEOPLE HAVE JUST BARELYACCEPTED T HAT 6-MO-OLDS CAN IMITATE AFTER 24 HR—AND EVEN THAT HAS BEEN DISMISSED BY THE “USUAL” ANTAGONISTS AND PIAGETIANS, WHO THINK IMITATION IS IMPOSSIBLE BEFORE 18 MONTHS OF AGE. SO, INSTEAD OF SHOWIG 1 PAIR FOR 1 DAY, YOU WILL SHOW A DIFFERENTPAIREACH DAY WITH A COMON MEMBER FROM ONE DAYTO THE NEXT. YKJU ARE ASKING HOW INFANTS REPRESENT INFORMATION THAT THEY MERELY PICK UP AND HOW, IF THEY DO, TO THEY INTEGRATE
I concluded a Group of infants displayed significant deferred imitation if the mean imitation score during the Phase 3 test was greater than the mean test score of a pooled baseline control group who did not experience any Phase 1 or Phase 2 training. The Test session was their only session. This baserate represents , in the population as a whole, without any training, the rate at which 6 month old infants spontaneously produce the target actions. And as you will see, The rate is very low. In these experiments I used only 6-month-old infants and followed the standard SPC procedure, with the exception that Phase 1 involved more than one pair of puppets and was broken into sessions. The demonstration and tests phases were video taped and coded later. We also examined the differing effects different preexposure regiments had on responding, but because of time constraints, much of the data I will be presenting today examines whether or not infants showed significant deferred imitation
Previously, we adapted the SPC procedure for the puppet imitation task by simultaneously exposing infants to a pair of puppets, A and B, before the demonstration and then “training” a response to one of the puppets (Puppet B) by modeling the target actions on one puppet of the pair. In the final phase, we tested infants for deferred imitation with the other puppet. This procedure exploited the fact that infants do not spontaneously generalize the modeled actions to a puppet other than the one on which the actions were originally demonstrated. If the infant imitated the actions on the other puppet, then we assumed that an association had been formed between the paired puppets in phase 1 and that this association mediated the transfer of responding from puppet B to puppet A.
A/B pairing = extinction Can they associate multiple pairs of puppets Preconditioning Than Demo than Test Here is the design of Experiment 1. Group C/A is the main experimental group. They saw a pair of puppets on day1, than a second pair of puppets on day 2. The target actions were modeled for them on the terminal puppet, C and then they received an imitation test on day 4. If this group showed significant deferred imitation that would demonstrate that 6-month-old infants can form associations between 2 pairs of puppets in Phase 1 Group C/A unpaired received the same training, but the were preexposed to the first puppets in an unpaired manner. One in the morning and then one in the afternoon Group B/A received paired presentations of the puppets during session 1, but saw puppet B alone on the second day. Group Extinction C/A received the same preexposure as group C/A paired, but in the afternoon after session 2, they were exposed to puppet B unpaired and alone. These groups were included to discover, if exposure to the common element alone (B) would extinguish Phase 1 associations.
the letter before the slash indicates the demostration and AXIS GROUPS Here are the results from experiment 1. The Y axis represents the mean imitation score for a group. In the groups label along the X axis the letter before the slash indicates the demostration and the Letter after the slash indicates the test puppet.. The dotted line represents the mean test score of the baseline control group . The asterisk above group C/A paired shows that this group's mean imitation score was significantly above baseline.. C/A unpaired did not show any responding during testing suggesting that puppets most be paired, exposed together, to defer imitation. Neither group B/A or Extinction C/A showed deferred imitation. Group extinction C/A received the identical training as the paired group, but did receive exposure to puppet B alone after Phase 1. Group C/A paired showed significant deferred imitation and demonstrated that infants can form an association between more than one pair of puppet during Phase 1 of SPC
How get from A(test) to C (demo and target actions) Direct A to C Or compound, explain extinction, but 6 month don’t generalize and see demo and test alone
In experiments 2 I examined if links could be added to the associative chain of Phase 1. If infants could form an association between 2 pairs of puppets could they form an associative chain if more links were added to the chain. Since in Experiment 1 infants with 2 paired preexposure session could defer imitation, we asked if the could show significant imitation with three pairs by adding an additional Phase 1 session during SPC One of our concerns was, that with exposure to so many different puppets , infants might form a ‘puppet’ category and treat any puppets the encountered similarly. So a group was included which received identical training but was tested with a novel puppet, one they had not seen during any phases of SPC
Here is the design of Experiment 2. Group D/A were exposed to a different puppet pair across 3 session on three days. The target actions were demonstrated for them on the terminal puppet D, and they were tested with puppet A. If this group performed the target actions significantly above the mean of the baseline control, if they deferred imitation, it would be an indication the 6-month olds could add even more links during Phase 1 of SPC. Group D/E received identical training to group D/A but they were tested with a novel puppet. Before I get to the results, I just want to say that I was sure that with such extensive preexposure, to so many different puppets, 6-month-old infants would generalize responding to a novel puppet. I didn’t expect infants to be able to retain specific memories of the puppet pairs.
Can THREE PUPPUT PAIRS ASSOCIATIVE MEMORIES REMAIN SPECIFIC In experiment 2, we saw no indication that exposure to multiple pairs of puppets disrupts imitation, and that the memory, of at least three puppet pairs remains specific to those puppets, Infants did not generalize responding to a novel puppet after three sessions of preconditioning or, As the original Barr study demonstrated, one pair of puppets. Our assumption has been that Infants were using a FORWARD associative chain at the time of testing A to B to C, and here to D, and that the retrieval cue, the test puppet (A) in the anchor of the chain. Though infants never are exposed to the training and test puppet at the same time they are able to significantly defer imitation even though they have never seen puppets A and C or A and D together, if no links in the chain are extinguished, if they are intact. However, if infants could use a backward associative chain at testing C to B to A, that would be an indication that the associations 6-month old infants form during preconditioning are bidirectional.
Term FORWARD FROM RETRIEVAL CUE FORWARD FROM PRECONDITIONING TRAINING
AFTER DEMO = before and after INDICATED THAT INFANTS ARE USING THE ASSOCIATIVE CHAIN AT PHASE 3 TEST CONTROL, NOW AFTER GENERAL ABILITY TO IMITATE In experiment 3 I examined if 6 month old infants could use a backward associative chain. And we explored this by keeping preconditioning the same but reversing the puppets used during the demonstration and test. In experiment 3 we also looked further into extinction training by moving extinction training from after preconditioning to after the demonstration. If exposure to the common element (puppet B) was still affective in disrupted the associative chain that would be an indication that we were correct in assuming that the puppet used during the imitation test is the retrieval cue for the memories infants are using to transfer responding from one puppet to another.
COMPAIRISION AC FIRST EXTINCTION WORKS FORWARD LIKE EXP1 CONTROL= IMITATION DOES NOT DISRUPT GENERAL IMITATION BUT GROUP A EXTINCTION C;;; DIFFERENTS REQUIRING FWD AND BACKWARD CHAIN The axis are the same as before. Groups that were required to use a forward chain are shown in blue, Groups C/A is from the Experiment 1. I’d like to start with group A/C in yellow, which had to make use of a backward associative chain. These group showed significant imitation, comparable to group C/A from experiment 1. Group C extinction C, here, also deferred imitation demonstrating that the extinction training did not generally disrupt imitation. Infants were perfectly capable of imitated on C after seeing B alone. . Exposure to the common element alone after the demonstration extinguished a forward associative chain just as it had before the Phase 2 in experiment 1, that would be group C extinction A However, A extinction C showed significant deferred imitation compared to the baseline control group. The results of this group suggested that perhaps their might be a difference between forward and backward associative chains in infancy
The latency to perform a response can be an indication of the difficultly of a task. FROM 1 ST TOUCH FORWARD THAN BACKWARD PERHAPS FOR 6 MONTH BACKWARD MORE DIFFICULT This graph is showing the latency of all the non extinction groups in the first 3 experiments, to perform the first target response, removing the mitten, during the imitation test. This latency is measured from the infants first touch of the puppet during testing As you can see the backward associative chain group took significantly longer, suggesting that a backward chain might be more difficult for infants. Here the Y axis represents the latency to 1 st remove the mitten in seconds.
Infants learn an enormous amount of information by merely observing their surroundings, but what they learn remains latent until they have a response and an opportunity to express it. In a classic experiment, Brogden (1939) introduced the sensory preconditioning (SPC) paradigm to study the latent learning of associations between neutral stimuli . The SPC paradigm has three phases: (1) Two stimuli (A, B) are repeatedly exposed in close temporal or spatial contiguity ; (2) a distinctive response is trained to one of the stimuli (A R1); (3) the subject is tested with the other stimulus (B). The transfer of responding to the untrained stimulus (B R1) but not to an equally familiar but unpaired stimulus is taken as evidence that an association was formed between A and B during the initial preexposure phase. Because the association that individuals learn during sensory preconditioning is latent at the time it is formed, it has been characterized as behaviorally silent learning (Domjan, 2003; Talk, Gandhi, & Matzel, 2002). Barr et al. (2003) replicated and extended Boller’s findings using a deferred imitation task. Six-month-old infants were exposed to two hand puppets simultaneously (A and B for 1 hr daily for 2 consecutive days; phase 1), and then three target actions were demonstrated on puppet A (phase 2). During the test (phase 3), the paired preexposure group transferred imitation of the target actions from puppet A to puppet B, but the unpaired preexposure control group did not. Subsequent research has examined how long infants can remember an association before they finally express it. Following two preexposure sessions, infants remember an association between two puppets for 1 week at 6 months and for 2 weeks at 9 months (Bullman et al., 2006). At both ages, however, infants remembered the association for only 2-3 days after one preexposure session. The basis for the retention benefit afforded by the additional preexposure session is unclear: Merely retrieving the memory of the association in Session 2 could have prolonged its retention. This notion is supported by evidence that 3-month-olds associated two paired (but not unpaired) hand puppets, and the memory of the association was maintained for 3 months by periodic reminders (exposure to puppet; Campanella & Rovee-Collier, 2005). These findings reveal that new learning acquired via mere observation can remain latent for a substantial period before it is finally used.
INFANTS GOT FROM PUPPET C TO A, NEVER PAIRED Here, infants transferred what they learned about the modeled target actions demonstrationed on Puppet C and transferred them to puppet A, Even thought the two puppets were never paired during preconditioning, they were treated as equivalent. The transitive inference was mediated by the common element of an associative chain, puppet B. Infants who saw the demonstration on puppet A and showed significant deferred imitation when tested with puppet C indicated that infants can retrieve both backward and forward associations Thought Piaget and many current developmental psychologist argue that young infants are cognitively and/or physiologically constrained from creating declarative memories, These data I have presented here today suggest that 6-month-old infants have comparable abilities and are capable of creating bidirectional associations. And they can do this at an earlier age than was considered ontogenetically plausible. Bidirectional associative chains increase the likely hood that memories can be activated and joined with stimuli that infants encounter, providing a useful mechanism for the preverbal infant while they learn the relationships in their environments.
