Innate Behaviours

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Innate Behaviours
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Behavioural Systems

• Complexity
• Observe behavioural endpoint
• Reductionism
• Constituent elements
• Simple systems interact producing complex
  outcomes
• Gestält

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Why Study Innate Behaviours?

• Evolved
• Learned behaviours have roots in innate
  behaviours
• Parallels between learned and innate behaviours
• Some innate behaviours modifiable
• Types of innate behaviours
• Homeostasis, reflexes, tropisms, modal action
  patterns, reaction chains

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Elicited Behaviours

• Behaviour occurs in reaction to an environmental
  stimulus
• For example
• Face moving stimulus in peripheral vision
• Sneeze if inhaling dust, a bug, etc.

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Homeostasis

• Internal balance of the body
• Drives
• Regulatory drives

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Osmotic Homeostasis

• Regulating body H2O level
• Example at a party
• Eat peanuts/popcorn/chips
• Increase salt concentration
• Thirsty...drink beer
• Increases H20 dilutes salt concentration
• But, alcohol diuretic
• Pee...decreases H20 increases salt concentration
  even more
• Thirsty ... drink more beer
• Pee even more salt concentration increased again
• Etc.
• Solution? Drink water!

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Control System

• Comparator
• Reference input
• Actual input
• Action system
• Output
• Feedback system (closed-loop system)
• Response lag

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Blood Salinity
Eat more peanuts!
Drink water!
Eat peanuts!
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Reflexes

• Stereotypic movement patterns
• Reliably elicited by appropriate stimulus
• Survival benefit

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Principles

• C.S. Sherrington
• Spinal animals (dogs)
• Threshold for activation
• Latency until response
• Irradiation of response

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Reflex Arc

• Monosynaptic
• One sensory and one motor neuron
• Polysynaptic
• One or more interneurons connect sensory and
  motor neurons
• Interneurons allow processing and/or inhibition
  within spinal cord
• All but simplest reflexes

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Patellar Reflex

• Monosynaptic
• Patellar tendon struck
• Stimulates stretch sensory receptors (muscle
  spindles)
• Triggers afferent impulse in sensory nerve fiber
  of femoral nerve leading to L4 of spinal cord
• Sensory neuron synapses directly with motor
  neuron, conveying efferent impulse to quadriceps
• Necessary for walking without conscious thought

en.eikipedia.org/wiki/FilePatellar-knee-reflex.pn
g
Animation
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Pupillary Light Reflex

• Controls diameter of pupil
• Greater light --gt pupil contracting
• Lower light --gt pupil expands
• Cranial nerves two sensory, two motor

en.wikipedia.org/wiki/FileCiliary_ganglion_pathwa
ys.png
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Tropisms

• Orientation or movement of whole organism
• Kinesis
• Movement random with respect to stimulus
• Taxis
• Non-random (directed) movement with respect to
  stimulus
• Control systems

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Simple Agent
Excitatory or inhibitory
Propulsion system

Sensor
-
Body
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Movement Environment
Perfectly homogenous
Non-homogenous
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Kinesis
Homogenous
Locally cool so stops
slower
fast
Non-homogenous
Locally cool so stops
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Only Slightly More Complex Agent
Excitatory or inhibitory

Propulsion system
-
Sensors

-
Body
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Taxis
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Taxis
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What Would This Do?
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Modal Action Patterns

• Originally fixed variable to some degree
• Species specific, often state dependent
• Sign stimulus activates a dedicated neural
  network (innate releasing mechanism)
• Go to completion in sequential

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MAPs

• Graylag goose
• Rolls displaced egg near its nest back with beak
• Sign stimulus displaced egg
• Remove egg during sequence
• Goose keeps pulling head back as if egg was there
• MAP video

www.cerebromente.org.br/n09/fastfacts/comportold_I
.htm
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Supernormal Stimuli

• Extreme version of sign stimulus
• Size
• Colouration
• Preference for supernormal stimuli
• Sometimes detrimental

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Beetles on the Bottle

• Gwynne Rentz (1983)
• Male Jewel beetles (Julodimorpha bakewelli)
• Colour and reflection of bumps on bottle as
  supernormal stimuli for female beetle

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Mimicry

• Code-breaking
• Brood parasitism
• Cowbird, cuckoo
• Noisier, more energetic behaviour
• Conveys urgent need for food

Reed warbler feeding cuckoo Wikipedia.org/wiki/Fix
ed_action_pattern
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Reaction Chains

• Initiated by a particular stimulus
• Progression condition dependent
• Starts with most appropriate behaviour in chain
• Can end before chain complete

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Reaction Chain
Stimulus
Action (behaviour)
Outcome (new stimulus)
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Reaction Chain
S1
A1
A2
A3
A4
S3
S2
S4
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Sequential Organization

• Functionally effective behaviour sequences
• Non-random
• Appetitive behaviour
• Early components of sequence
• Consummatory (i.e., completion) behaviour
• End components of sequence

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Variability to Fixed

• Appetitive behaviours
• Can take a variety of forms dependent upon
  situation
• Consumatory behaviours
• Highly stereotypic

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E.g., Foraging

• General search mode
• Focal search mode
• Food handling
• Injestion

General to specific
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Habituation and Sensitization

• Simplest form of Learning

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Habituation

• Decrease in a response following repeated
  stimulus presentation
• Note not everything that results in a decrease
  in response is habituation

Sensitization

• Increase in a response following repeated
  stimulus presentation

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Time Course

• Habituation
• Short-term
• Seconds to minutes
• When many stimuli presented frequently
• Long-term
• Hours to days
• When fewer stimuli presented less frequently
• Sensitization
• Short-lived
• Seconds to minutes

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Stimulus Specificity

• Habituation
• Quite stimulus specific
• Stimulus generalization of habituation
• Sensitization
• Not very stimulus specific
• But not totally generalizable (e.g.,
  sensitization to shock only generalizes to other
  exteroceptive cues)

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Spontaneous Recovery

• Post habituation or sensitization
• Return of original level of responding
• Due to passage of time

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Dishabituation

• Quickly restores response after habituation
• Exposure to extraneous stimulus
• Essentially, sensitization
• Habituation and sensitization working in
  opposition

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Sensory Adaptation

• Temporary change in neural response to a stimulus
  as a result of the preceding stimulus
• Habituation is response specific sensory
  adaptation is not

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Response Fatigue

• Due to use neurons or muscle fibers no longer
  functioning optimally or at all
• Habituation is stimulus specific, response
  fatigue is not

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Physiological Mechanisms of Habituation

• Neurologically simple
• Seen across species
• Example Aplysia

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Aplysia Gill-Withdrawal Reflex
gill withdrawal muscle
sensory receptor
sensory neuron
motor neuron
interneuron
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Synaptic Effects of Habituation

• Decrease in excitatory conductance
• No change in postsynaptic sensitivity
• Reduced neurotransmitter release
• Decrease in active zones

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Neurochemical Level Calcium
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Learning Through Habituation

• Learning without new axons/synapses
• Chemical change at synapse
• Plasticity

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Opponent-Process Theories

• Assumes two opposing components
• Observable behaviour
• Net sum of two underlying processes

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Dual-Process Theory of Habituation

• Groves Thompson (1970)
• Competitive
• Habituation process and sensitization process
• Behaviour of habituation or sensitization is the
  net sum effect of the two processes

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SENSITIZATION
HABITUATION
S


Net
S
Net
H
H
-
-
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Habituation Process

• S-R system
• Shortest neural path connecting sense organs to
  muscles
• Reflex arc
• Activated with each presentation of eliciting
  stimulus

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Sensitization Process

• State system
• Nervous system components determining organisms
  general level of responsiveness
• Only activated by arousing events
• Altered by drugs, emotional experiences

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Implications

• S-R system activated by each stimulus that
  elicits a response
• Each activation is stimulus specific
• S-R activation and resultant habituation process
  universal features of elicited behaviour
• State system only activated by particular stimuli
• Not stimulus specific
• Both processes decay with time --gt spontaneous
  recovery

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Emotions

• Solomon Corbit (1974)
• Emotional reactions are biphasic
• Primary reaction becomes weaker with repeated
  stimulations
• Weakening of primary reaction accompanied by
  strengthening of after reaction
• Change with experience

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Examples

• Christmas
• Excitement and depression
• Young
• Older
• Incidence of suicides post-holidays
• Drug tolerance
• Thrill seekers
• Romance

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OPT of Motivation

• Homeostatic theory
• Underlying neurophysiological mechanisms
• Emotional stability
• Emotion-arousing stimuli pushes emotional state
  out of stability

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Processes

• Primary (a)
• Quality of emotion with stimulus
• Opponent (b)
• Elicited by primary process
• Opposite emotion

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OPT of Emotional Response
peak of primary affective reaction
adaptation phase
Intensity of primary affect
steady level
Hedonic Scale
0
decay of after-reaction
Intensity of affective after-reaction
peak of affective after-reaction
stimulus
Time
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Habituation
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