The Modification of Instinctive Behavior

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The Modification of Instinctive Behavior

• Chapter 3

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Instinctive Systems

• Lorenz Tinbergen evolution occurs when a
  species incorporates environmental knowledge into
  its genetic structure.
• Greylag goose and egg-rolling.
• Learning can sometimes modify instinctive
  behavior even though the fixed action patterns
  are innate.

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Energy Model

• Action-specific energy builds up but is blocked
  (inhibited).
• The energy motivates appetitive (approach)
  behavior.
• Presence of a sign stimulus releases the energy
  by stimulating an innate releasing mechanism.
• The behavior occurs as a fixed action pattern (or
  chain of actions).

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Releasing Signs

• Releasing signs can be complex
• Grayling butterfly signs include darkness of
  female, distance from male, and pattern of
  movement.
• Intensity of the sign influences the behavior but
  so does the amount of accumulated energy (time
  since the last response).

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Hierarchical System

• Specific behaviors are controlled by a central
  instinctive system.
• Energy can accumulate at each level in the
  system.
• Hormones generate energy.
• Release of energy at higher levels flows to lower
  levels.
• The sign stimulus determines which behavior will
  occur.

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Conflicting Motives

• If two incompatible signs appear at the same
  time, energy flows to a third instinct system.
• This third behavior is called displacement.

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Conditioning Affects Behavior

• Conditioning experiences can change sensitivity
  to releasing signs.
• Only the consummatory response (eating, mating)
  at the end of a chain cannot be changed.
• Conditioning fine tunes the response to the
  environment and enhances survival.

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Lorenz Energy Model
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Criticisms of the Energy Model

• Best viewed as a metaphor.
• The brain does not literally accumulate energy in
  any centers and nothing flows.
• Willows Hoyle alternating contractions in sea
  slug allow it to escape from a starfish.
• Brain areas producing this response do not
  correspond to energy model.

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Acquired Changes in Response

• Habituation response to a repeated stimulus
  decreases with experience.
• Sensitization response to a repeated stimulus
  increases with experience.
• Examples
• Ingestional neophobia, fear of new food
• Startle response

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Experimental Evidence

• Rats drink little saccharin water at first but
  increase over time.
• Loud tones (110 db) produce different responses
  depending on the background noise (60 vs 80 db).
• Habituation occurred at 60 db
• Sensitization occurred at 80 db
• A loud background is arousing, leading to greater
  reactivity, not less.

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Conditions Producing Change

• More intense (stronger) stimuli produce stronger
  sensitization, less likely to produce
  habituation.
• Greater sensitization and habituation occur when
  the stimulus is repeated frequently.
• Changes in the stimulus prevent habituation.
• Turkeys habituate but respond again if the shape
  changes.

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Conditions (Cont.)

• Sensitization can occur to many kinds of stimuli
  but habituation occurs only with innate
  responses.
• Habituation and sensitization are transient (go
  away after seconds or minutes between stimuli).
• Except long-term habituation.
• Dishabituation response returns when a
  sensitizing stimulus occurs.

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Dual Process Theory

• Groves Thompson suggest that sensitization
  originates in the central nervous system.
• Drugs that stimulate the CNS increase readiness
  to respond.
• Garcia suggests that the ability to modify innate
  reactions has considerable adaptiveness.

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Evolutionary Theory

• Eisenstein et al. suggest that this is a
  fine-tuning of sensory stimuli to recognize
  important stimuli.
• Habituation sensitization are non-associative
  forms of learning.
• Their function is to modify sensory thresholds to
  adjust to environment.
• High responders low responders adjust in
  different ways to same stimulus.

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Cellular Modification Theory

• Aplysia California sea slug
• Learning can permanently alter the functioning of
  neural systems.
• The change takes place at the synapse of the
  neurons.
• Stimulation by an external stimulus produces the
  change.

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Dishabituation

• Habituation disappears when the environmental
  stimulus changes.
• In the aplysia, the neural status may return to
  the previous condition.
• An alternative view is that sensitization occurs
  to modify the responding.
• The mechanism remains unclear.

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Opponent-Process Theory

• An explanation for addictions.
• All experiences produce an affective reaction
  (pleasant or unpleasant) called the A state.
• This reaction gives rise to its opposite called
  the B state.
• B state is less intense and lasts longer.
• Over time, the A state diminishes and the B state
  increases.

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Opponent Process Model
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The Addiction Process

• Tolerance diminished A state.
• Withdrawal increased B state.
• Addictive behavior is a coping response to the
  change in B state.
• People try to enhance A state to offset the
  unpleasantness of the B state.
• Without withdrawal symptoms there is no addictive
  behavior.
• Time prevents B state strengthening.

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What Sustains Addiction?

• The B state is a non-specific aversive feeling.
• Anything similarly aversive will motivate the
  addictive behavior, even if it has no relation to
  the substance.
• Daily life stress produces a B state that results
  in behavior to create an A state.
• Parachute jumpers create a B state in order to
  feel the A state.