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30/01/2013
1
Learning
Hans Erhard
erhard@agroparistech
UE Neurobiology and Behaviour 2012/13 What to expect
• habituation
• classical conditioning
• operant conditioning
• definition, examples, application
Habituation
• Repeated exposure to a frightening stimulus without consequences will result in a decreased response level
Why should we spend time on “taming” animals?
• frightened animals are difficult to handle
• it can be very hard (dangerous?) work for one
• it may take two people
• it takes longer
• hurdles often low (90 cm) to help with work, but: Sheep may try to jump out of handling pens (injuries)
Trade - off
+ work is easier and faster
+ lower risk of injury to sheep and shepherd
– time taken to ‘tame’ them
• useful when animals (sheep) are:
– very wild
– have to be handled repeatedly
Habituation
• Decrease of reaction with repeated exposure
• If not, or if even increase of reaction: situation is too aversive to habituate to
• Solution: – Flooding
– Systematic desensitization
repetition
str
eng
th o
f re
action
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Four small steps of habituation
divide procedure into small steps
move to next step only once the previous one works OK!
• Elements of ‘putting belt on’: – Step 1: being moved into a pen
– Step 2: being confined in a small pen
– Step 3: being close to a human
– Step 4: being touched
Initial training to enter handling pen
• What you need:
• pen: 4.5 x 6 m
• gate
• two light-weight
hurdles
• group of ‘wild’ sheep (why a group?)
Step 1: Being moved into a handling pen
Step 2: Being confined in a small pen
Step 3: Being close to a human
a) outside pen
b) inside pen
Step 4: Being touched
• front is bad - rear is less bad start at rear
• being touched is bad - being scratched feels good
• they need to learn that being touched can feel good
• look at their ears when you touch them
• if you can’t scratch them for long enough, return to Step 3
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Calming results
• sheep stand to be touched, clipped and have belts attached to chest
• work is:
– less hard
– less stressful
– less dangerous
• approximately 2-3 hours to tame 24 sheep
• small steps: habituate to one step before moving on to the next
• Is it worth the extra time?
Stress and cognitive performance
• stress – response curve is inverted U-shaped
• performance best between coma and blind panic
• increasing pressure can be counter-productive!
per
form
ance
stress
T-maze choice test for pigs
right left
- 5 min in start box
- choice between food and no food
- food visible from start box
- side alternating randomly
- 8 trials per pig
- 5 pigs
van Rooijen & Metz, 1987. AABS 19: 51-56
Results
• no preference for compartment with food
0
25
50
75
100
preferred side
other side n
um
ber
of
tria
ls
• strong side preference
van Rooijen & Metz, 1987. AABS 19: 51-56
T-maze choice test for pigs
right left
- pigs seemed nervous in the start box
Alteration:
- time reduced:
30 sec in start box instead of 5 min
van Rooijen & Metz, 1987. AABS 19: 51-56
Results
• strong preference for compartment with food
0
25
50
75
100
preferred side
other side
nu
mb
er
of
tria
ls
• no side preference
van Rooijen & Metz, 1987. AABS 19: 51-56
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Stress and cognitive performance
0
25
50
75
100
right wrong
nu
mb
er
of
tria
ls
per
form
ance
stress
per
form
ance
stress
0
25
50
75
100
right wrong
nu
mb
er
of
tria
ls
Stress and cognitive performance
• sometimes it’s better to reduce pressure
• push less and get more done
• cattle prod etc
• patience
• proper handling facilities
• learning requires the right
level of stress!
Habituation
• Decrease of reaction with repeated exposure
• If not, or if even increase of reaction: situation is too aversive to habituate to
• Solution: – Flooding (full exposure to
phobia at its worst)
– Systematic desensitization (elements of fear addressed in small steps)
repetition
stre
ngt
h o
f re
acti
on
Classical conditioning
http://www.experiment-resources.com/classical-conditioning.html
Classical conditioning summary
• Two stimuli occur at the same time
• Connotations/associations change
• No reward/punishment
• Other examples?Does it matter?
Coca Cola versus Pepsi
Average Coke preference in 15 trial task: 7.5 ± 0.8 for Coke drinkers 6.8 ± 0.5 for Pepsi drinkers.
McClure et al 2004. Neuron 44: 379–387
Pepsi + ? ? + ?
Coke + ? ? + ?
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• no preference in a blind test • strong preference for Coca Cola in non-blind test • choice based on something else classical conditioning through advertising colour ? (blue vs red) music ?
Gender stereotypes: men are better at maths
0
1
2
3
4
5
6
7
8
male female
affirmed
baseline
challenged
b
a ab
a b b
Smith & Postmes, British Journal of Social Psychology 2011
same gender discussion groups, either affirm stereotype or challenge it; maths test later, score out of 11
What happened? Self-fulfilling prophecy? Classical conditioning? Beware of stereotypes (race, gender etc.) !
Operant conditioning
behaviour + positive or negative consequence
increase or decrease of this behaviour
Learning schedules
• fixed ratio
• fixed interval
• extinction: no more reward/punishment or association
Operant conditioning
Reinforcement
Behaviour Punishment
Behaviour
Positive
Add (+)
Negative
Take away (-)
bad good
bad good
Operant conditioning
Reinforcement
Behaviour Punishment
Behaviour
Positive
Add (+)
Negative
Take away (-)
Positive punishment Positive
reinforcement
Negative reinforcement
Negative punishment
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Operant conditioning summary
• a behaviour followed by a consequence
• behaviour changes in frequency
• reward/punishment
• Which method is (currently considered) the best?
• What’s the difference between operant and classical conditioning?
• Other examples? What about teaching?
What do they learn?
• Does the rat learn “turn left”
or
“food is over there (south)”
or
“This is a maze experiment?”
Cognitive maps
Cognition: the mental process of knowing, including aspects such as awareness, perception, reasoning, and judgment; mental maps.
