Transcript Cognitvie Psychology

Elicited or Unconditioned Behavior
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Occurs without past experience
Modifiable with experience (examples:
habituation and sensitization
Some Types of Elicited Behaviour
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An eliciting or unconditioned stimulus elicits a
response without any prior learning
Types of Elicited Behaviour
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Simple Reflex
Orienting Reflex
Taxis (taxes)
Kinesis (kineses)
Fixed/Modal Action Patterns
FAPs/MAPs
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Sequence of behaviors directed at the
eliciting (sign or releasing) stimulus
Sometimes requires underlying drive
(hydraulic model)
Vigor of response depends on how closely
the sign stimulus corresponds to the ideal
stimulus (e.g., cute baby)
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Small (non-ideal), Normal (ideal), Supernormal
(exaggerated ideal)
Releasing Stimulus
Back
Back
Supernormal stimulus
An accurate 3-dimensional model of a herring gull's
head (a), and a 'supernormal' bill (b).
Supernormal stimulus
Habituation
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a simple type of learning which is shown by a
change in elicited behaviour over trials
defined as a reduction in responsiveness
(frequency, magnitude) over successive trials
sometimes short-lasting and sometimes long
lasting
Habituation-One Type of Modifiability
Eric Kandel and Aplysia
Kandel`s Experiments
Touch
Siphon
Gill
Withdrawal
Habituation
gill withdrawal
touch
Forms of Habituation
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Short-Term
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lasts only a few minutes
best if stimulus applied at short intervals (2-s)
Long-Term
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lasts weeks
best if stimulus applied at longer intervals (30-s)
Simplified Circuit
What’s the Mechanism of Short-term?
decreases in
synaptic transmission
loss of skin
sensitivity
decrease in motor
synapse
fatigue
Not Muscle Fatigue
Spontaneous
Evoked
Pinsker et al., (1970) Science 167:1740
What’s the Mechanism of Short-term?
decreases in
synaptic transmission
loss of skin
sensitivity
decrease in motor
synapse
fatigue
Not Motor Synapse
Before
skin
SN
After
electrical
MN
record
gill
Kupfermann et al., (1970) Science 167:1743
What’s the Mechanism of Short-term?
decreases in
synaptic transmission
loss of skin
sensitivity
decrease in motor
synapse
fatigue
Skin Sensitivity?
Stage 1
touch
skin
SN
MN
record MN
activity to assay
habituation
gill
Kupfermann et al., (1970) Science 167:1743
Not Skin Sensitivity
touch
skin
SN
block
MN
record MN
activity to assay
habituation
gill
Kupfermann et al., (1970) Science 167:1743
What’s the Mechanism of Short-term?
decreases in
synaptic transmission
loss of skin
sensitivity
decrease in motor
synapse
fatigue
Mechanism of Short-term Habituation
Decrease in neurotransmitter
released at the synapse with
both the motor neuron and the
interneuron!
Mechanism of Long-Term Habituation
Change in the number of synapses!
Some Properties of Habituated
Responses
1. Spontaneous Recovery
2. Dishabituation
3. Generalization
Spontaneous Recovery
Hi
Response
Stimulus
Time
Passes
Lo
Number of Presentations
Dishabituation
Hi
Response
Stimulus
Novel
Event
(no time
passes)
Habituation
Dishabituation
Lo
Number of Presentations
Generalization
Sensitization- Another Type of
Modifiability
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enhanced response to a “benign” stimulus after
exposure to a “noxious” one (most common)
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for example, startle
enhanced response after repeated presentations of a
“not so benign” stimulus (less common)
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for example, kindling
Rat
Startle
Human Startle
Kindling
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repeated stimulation of hippocampal cells
increases responsiveness
after being sensitized, very little stimulation is
required to produce the seizures
related to epilepsy
Dual Process Theory
Competition between two separate processes
1. S-R System: Habituation
2. State System: Sensitization
Examples
S
S
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+
NET
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H
NET
H
Trials
Trials
Conditions Favouring Habituation
1.
2.
3.
4.
5.
6.
Calm organism
Shorter interstimulus intervals
Less variable interstimulus intervals
Low intensity
Less complexity
More trials
Interstimulus Interval
Complexity
Looking
Time
Trials
Imagine………
Kendra is an overly anxious person. She worries
about the smallest things. Some examples of the
unpleasant symptoms she experiences include
excessive sweating, heart palpitations, and a fitful
sleep. Her anxiety places her at risk for depression,
heart disease, and diabetes. A genetic test reveals
Kendra has a vulnerability in the promoter region of
her serotonin transporter gene. Her doctor tells her
that if her mother had been more loving and attentive
when Kendra was younger, she might have been
calmer. The doctor maintains experience can
program calmness, and calmness acquired by
experience is inheritable.
Epigenetics and Early Experience
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Genes affect bodily processes, including emotional
regulation
Two copies of the “short” version of a promoter for the
serotonin transporter gene is a risk factor
Maternal Behavior
licking and grooming (LG) and arched-back nursing (ABN)
High LG-ABN
mothers
Low LG-ABN
mothers
Attentive Mothering
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Licking and arched-back nursing by mother
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an immediate “calming” effect on baby rats in the
first week after birth
a long-term reduction in stress responsiveness
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the promoter for the short version of serotonin
transporter gene is “switched on” by attentive mothering
so, a vulnerable pup with two short copies of the
promoter for the serotonin transporter gene is cured by
its mother’s licking (short gene works better)
this environmental effect is passed along to the pup’s
own offspring
Brain of Vulnerable Baby Rat
high LG-ABN
mother
short gene
expressed
less anxiety
Cross-fostering Studies
Imagine………
Kendra’s doctor gives her a prescription for a pill that
will promote the activity of the malfunctioning gene.
No other therapy is necessary. Kendra’s children
inherit the faulty gene, but its function is enhanced.