CHAPTER 11

EARLY LEARNING AND

BEHAVIOR

Learning Phenomena

Nonassociative Associative/Cognitive

•Classical conditioning

•Instrumental conditioning

•Rule learning

•Social learning

•Habituation

•Short term

•Long term?

•Sensitization

•Short term

•Long term?

General Specific

•Human language

•Song learning

•Imprinting

Tentative classification of learning phenomena

We have covered conditioning before, but

now we will be looking at these effects

from a developmental perspective

Fertilization

Birth

Weaning

CNS maturation

Sexual maturation

0

21

~40

~45

GD 19: Fetal learning

PND 5: Second-order conditioning

PND 17: Long-term recall of fear conditioning

PND 24: Successive negative contrast

-21

PND 1: Conditioned flavor aversion, instrumental conditioning

PND 3: Conditioned odor preferences, habituation

PND 14: Auditory orientation

PND 10: Sensitization, latent inhibition

PND 11: Fear conditioning

PND 12: Partial reinforcement extinction effect

PND 16: Variable magnitude of reinforcement extinction effect

PND 21: Magnitude of reinforcement extinction effect

Maturation of

hippocampal

granular cells

You are familiar with some of the specific

examples chosen here from our section on

learning and cognition. Here you will learn

how these effects develop in infant rats.

The laboratory rat as a model for behavioral developmental studies

PND 2 PND 3 PND 5 PND 7

PND 9 PND 13 PND 16 PND 21

Early development of the rat PND: post-natal day

Infant rat is really helpless, depending on

the mother for nourishment and protection.

Starting on PND 9-10, infants have sufficient motor maturation

to walk around and can be trained in running tasks (runway).

Infant eats

solid food and

becomes

independent

of mother

Fetal learning in rats

Stretch action pattern

(an adaptation to search

for the mother’s nipple

after birth)

Wipe action pattern

(an adaptation to eliminate

harmful substances)

Appetitive behavior

Aversive behavior

Fetal learning in rats

Nipple

Sucrose

Pairings with milk

suppresses a behavior

aiming at eliminating an

aversive stimulus.

Pairings of an appetitive

stimulus (sucrose) with

an aversive stimulus

(lemon) increases

conditioned activity.

Even the brain of a slowly-developing mammalian

fetus is capable of associative learning.

Second-order conditioning in infant rats

Orange vs. Garlic

Second-order

conditioningControl 1 Control 2

Phase 1

Phase 2

Test

Orange→Lemon

Lemon→LiCl

Orange vs. Garlic Orange vs. Garlic

LiCl→Lemon

Orange→Lemon

Lemon→LiCl

Orange, Lemon

(backward)(paired)

(paired)

(paired)

(paired) (unpaired)

Pairings in both

phasesPairings only in

Phase 2

Pairings only in

Phase 1

Lemon signals

sickness

Orange

signals lemon

Garlic better

than orange

Second-order conditioning in infant rats

PND

PND

P/P: paired in Phase 1, paired in Phase 2

B/P: backward in Phase 1, paired in Phase 2

P/U: paired in Phase 1, unpaired in Phase 2

First-order conditioning (Phase 1):

•The lower the bar, the higher the aversion.

•Groups P/P and P/U avoided the lemon.

•Group B/P had backward pairings and did

not avoid the lemon.

•No age differences.

Second-order conditioning (Test):

•The lower the bar, the higher the aversion.

•No evidence of SOC at PND 2-4.

•SOC in Group P/P at PND 6-8.

•Groups B/P and P/U were controls and did

not avoid the lemon at any age.

•SOC emerges between PND 4 and 6.

Fear conditioning in infant rats

PND

Tone + Lever

Conditioned

suppression

Unpaired

control

Lever→Food

Tone→Shock

Tone + Lever

Tone, Shock

Lever→Food

(unpaired)(paired)

(paired) (paired)

Pavlovian

Instrumental

Transfer

test

Tone suppresses

lever pressing

Tone does not

suppress lever

pressing

Suppre

ssio

n R

atio

Trials

Successive negative contrast in infant rats

Age: 16-17

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

Downshifted

Unshifted

Age: 20-21

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

Age: 25-26

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

Mean

Sp

eed

(cm

/s)

Downshifted

Unshifted

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

0

20

40

60

80

0 2 4 6 8 10

6-Trial Blocks

Preshift Postshift

Run → Small

Run → SmallRun → Large

Run → Small

Downshifted

Unshifted

Preshift Preshift PreshiftPostshift Postshift Postshift

•The SNC effect emerges

gradually during the first 25

days of life.

•This emergence correlates with

the maturation of the

hippocampus.

Development of dendritic spines.

(A) The morphologies of dendritic protrusions

are visualized by green fluorescent protein

(GFP) in cultured hippocampal neurons at 1

week (left) and 3 weeks (right). Bar, 2 µm.

(B) A hypothetical model for dendritic spine

development. Synaptic contacts between

axons and dendritic filopodia are thought to

trigger the morphological change of dendritic

protrusion to spines. Differentiation of

presynaptic boutons might also be triggered

by these axo-dendritic contacts.

Successive negative contrast:

SNC,

PND 25-26

Development of learning phenomena involving surprising nonreward

Maturation of the hippocampal formationPND 11

(Response persistence)

PND 25(Response inhibition)

Single alternation patterning:

PND <11

Partial reinforcement extinction effect:

PREE, PND 12-14

Variable magnitude of reinforcement extinction effect:

VMREE, PND 16-18

Partial delay of reinforcement extinction effect:

PDREE, PND 16-18

Magnitude of reinforcement extinction effect: MREE, PND 20-21

Early Learning

Infantile Amnesia

Dispositional Learning

Forgetting of events that happened

early in life.

Early experience that shapes the

personality of the animal.

Precocial and altricial mammals and birds

Precocial mammal:

the giraffe

Altricial mammal:

the opossumPrecocial animals

are born with a

mature sensory and

motor systems, and

can move around

within minutes-

hours.

Altricial animals are

born in a very

immature state.

Opossums are

actually embryos at

birth.

Acquisition is

similar across

ages with a

zero retention

interval

Age at

acquisition

Infantile amnesia in an altricial mammal: rat

Recall is even more impaired when

acquisition occurred early in life when

the retention interval is lengthened

•Rats received fear conditioning in a black compartment and then were tested for

preference between a black (dangerous) vs. a white (safe) compartment.

•Rats that recall the fear experience spent more time in the safe compartment.

Retention is poor

when acquisition

occurred early in life

0

20

40

60

80

100

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

10-Trial Blocks

Co

rre

ct R

esp

on

ses (

%)

5-Day Olds

100-Day Olds

0 Trials 20 Trials 40 Trials 100 Trials

0

20

40

60

80

100

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

10-Trial Blocks

Co

rrect

Resp

on

ses (

%)

5-Day Olds

100-Day Olds

Amount of Original Training

0 Trials 20 Trials 40 Trials 100 Trials

Infantile amnesia in a precocial mammal: Guinea pig

Acquisition is

similar across ages

Recall after a

75-day retention

interval is

similar across

different

amounts of

training

•Guinea pigs are

precocial.

•At birth, their

maturation is

advanced as far as

behavior and nervous

system.

•The lack of infantile

amnesia suggests

that this is related to

neural maturation.

Early Learning

Infantile Amnesia

Dispositional Learning

Forgetting of events that happened

early in life.

Early experience that shapes the

personality of the animal.

Dispositional Learning

Group Phase 1 Phase 2 Vacation Phase 3 Phase 4PND 17-18 PND 19-21 PND 71-72 PND 73-74

--------------------------------------------------------------------------------------------------------------------------------------------

CR-Ext Run→100% Food Run→NoFood 50 days Run→100% Food Run→NoFood

PR-Ext PRF Run→50% Food Run→NoFood 50 days Run→100% Food Run→NoFood

CR-NoExt Run→100% Food No training 50 days Run→100% Food Run→NoFood

PR-NoExt Run→50% Food No training 50 days Run→100% Food Run→NoFood

--------------------------------------------------------------------------------------------------------------------------------------------

•Adults showed the PREE (Phase 4) whether or not they had extinction experience (Phase 2),

even after a 50-day vacation, and even after interpolated CR training (Phase 3).

•Conclusion: no infantile amnesia for learned persistence in extinction—dispositional learning.

Original Training: 17-18 Days

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4

8-Trial Block

Ru

nn

ing

Sp

ee

d

CR-ExtPR-ExtCR-No ExtPR-No Ext

Original Training: 28-29 Days

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4

8-Trial Blocks

Ru

nn

ing

Sp

eed

Original Training: 65-66 Days

0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 48-Trials Blocks

Ru

nn

ing

Sp

ee

d PR

CR

Tool use in chimpanzees (hammer and anvil)

Video

https://www.youtube.com/watch?v=o2TBicMRLtA

Duration: 2:11 min

• Infant chimpanzees take years before they master the technique of cracking

nuts with a stone or a stick used as a hammer and a rock used as an anvil.

•This type of tool use is part of a local culture, since chimps in other populations in Western Africa

may have all the components, but do not have the habit.

•This is possibly an example of dispositional learning (and culture).

Language and social learning

https://www.youtube.com/watch?v=ZRz7Xwi1ypU

Duration: 13:03 min

Video Bird songs and human language• Vocal learning is rare in nature. Zebra finches learn

one song, whereas canaries learn new songs every

breeding season, and parrots add new vocalizations

throughout their lives.

• In the human brain and also in the brain of songbirds,

there are areas involved in comprehension and areas

involved in production. Their communication is

essential to produce normal vocalizations.

• Stuttering is a speech disorder that occurs in humans.

Something similar was found in zebra finches.

• In both humans and zebra finches, brain activity in

individuals that vocalize normally is represented in a

much larger area than in individuals that stutter.

• How do humans and songbirds end up with similar vocal skills and even similar disorders?

• A study of an English family that exhibited a rare speech pathology that prevented many of its members to

produce the appropriate songs found that they had a single gene with a different sequence: FOXP2.

• FOXP2’s expression is enhanced during periods of song learning and reduced when birds do not sing.

• However, FOXP2 is a gene present in many animals, even in insects and fish.

• Genetic regulation may hold the key to vocal communication by setting pathways that integrate information in

brain areas responsible for comprehension and production.