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PSY 402. Theories of Learning Chapter 2 – Learning and Adaptation . Learning Enables Adaptation. The ability to adapt to one’s environment with experience enhances survival.

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PSY 402

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Psy 402 l.jpg

PSY 402

Theories of Learning

Chapter 2 – Learning and Adaptation


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Learning Enables Adaptation

  • The ability to adapt to one’s environment with experience enhances survival.

  • Those organisms able to adapt were more likely to survive and thus were selected by natural selection.

  • Example of survival value of a behavior:

    • Black-headed gulls and eggshells

    • Kittiwakes who nest on cliffs don’t remove shells


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Fixed Action Patterns

  • Fixed behavior sequences that are released by an environment signal.

    • Triggered by a releaser, also called a sign stimulus

    • Not learned – built in to the genes, innate

    • Stereotyped – occur the same way each time and in each person or organism

  • Eibl-Eibesfeldt considered smiling & eyebrow flashing to be a human fixed action pattern.


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Modification of Innate Behaviors

  • Even behaviors that are innate can be modified through conditioning.

    • Gull chicks get better at pecking at their parents’ beaks to get food – more accurate.

  • Conditioning experiences can change sensitivity to releasing signs.

  • Conditioning fine tunes the response to the environment and enhances survival.


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Acquired Changes in Response

  • Habituation – response to a repeated stimulus decreases with non-threat experience.

  • Sensitization – response to a variety of stimuli increases with a single threat experience.

  • Examples:

    • Ingestional neophobia, fear of new food

    • Rats orient less toward light, startle decreases

    • Chicks are less frightened by shadows flying overhead with repeated exposure.


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Instrumental Adaptation

  • Instrumental learning (S-R) occurs when a voluntary behavior (R) becomes associated with a stimulus (S) because of its effect.

    • Consequences can be either rewards or punishments.

  • Rewards and punishments are defined by their effect on behavior.

    • A reward increases behavior

    • A punishment decreases behavior.


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Reinforcement

  • Reinforcement occurs when the association between a stimulus and a response to it is strengthened.

  • Positive reinforcement occurs when a behavior is rewarded.

  • Negative reinforcement occurs when a behavior results in avoidance or escape from a bad consequence.


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Shaping

  • How can a behavior be reinforced if it never occurs naturally (or accidentally)?

  • Shaping is a process where a complex or unnatural behavior is learned as a series of steps that are successively rewarded.

  • By rewarding successive approximations to the desired behavior, eventually the target behavior is learned.


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Classical Conditioning Adaptation

  • Organisms learn to recognize and respond selectively to the signals that are important in their environment.

  • Cues associated with food evoke digestion: salivation, gastric juices, insulin secretion.

    • Taste aversion learning – illness makes us avoid foods that were eaten just prior to feeling sick.

    • Food preferences are associated with nutrients.


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Examples of Conditioning

  • Popcorn at the movies.

  • Fear of flying -- stronger with more turbulence (a stronger UCS).

  • An antelope shying away from low tree branches.

  • Nausea at the smell of alcohol after a hangover.


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Territoriality

  • Environmental cues can become associated with sexual rival males in gourami fish.

    • Pairing the light with the rival signaled the other fish to prepare so it was able to be more aggressive.

    • Presenting the light without pairing it with the rival had no effect.

  • Courtship behavior can also be conditioned, leading to more successful nestbuilding, etc.


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Fear Conditioning

  • Freezing is a universal response to threat.

    • Animals that freeze are less likely to be attacked.

  • Fear is an anticipatory pain response.

    • It occurs in response to stimuli that have been aversive in the past and motivates escape or avoidance behaviors.

    • Fear also releases endorphins in rats who are confronted by the smell or sight of a cat.


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Conditioning and Addictions

  • Drugs can be associated with environmental cues present when the drugs are taken.

  • Instead of the drug response being conditioned, an opposite adaptive response is conditioned that lessens the drug’s effect.

    • This is called drug tolerance.

  • Taking a drug under novel circumstances can produce a drug overdose because the compensatory effect is not present (no cues).


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Sign Tracking (Auto-Shaping)

  • Sign tracking occurs when a stimulus (cue) in the environment is associated with reward or punishment.

    • The sign stimulus motivates approach or avoidance behavior because of what it signals.

  • Negative sign tracking occurs when a sign motivates withdrawal instead of approach.

  • Some signs signal safety because they mean a bad thing is less likely to occur.


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Extinction

  • Associations are learned when they enhance survival, but conditioning decreases when the expected consequence no longer occurs.

  • Extinction occurs with both instrumental and classical conditioning.

    • Spontaneous recovery occurs after extinction has been learned, but a break in exposure to the stimulus occurs.

    • After spontaneous recovery, extinction returns.


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Timing of Stimuli

  • The strength of both instrumental and classical conditioning depends on the timing of events.

  • Reward or punishment must immediately follow the emitted response in order to strongly affect behavior.

  • Two stimuli must occur close together in time in order for them to be associated with each other.


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Size of the Stimuli

  • The strength of both instrumental and classical conditioning also depends on the size of the stimuli.

  • Larger rewards produce a stronger response than smaller ones.

  • More intense stimuli are better signals and evoke greater conditioned responses.

    • More fear, more saliva.


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Preparedness Affects Learning

  • Both instrumental and classical conditioning are affected by preparedness (the innate nature of the organism).

  • Flavor aversion learning is easier with taste cues than with visual cues, but not shock.

  • Rooting behaviors interfere with learning for pigs trained to put a wooden coin in a “bank”.

  • Some hamster behaviors are easier to learn.


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Humans Show Preparedness

  • Humans show preparedness too, appropriate to our species.

  • Nausea can be associated with tequila but not with friends or a shot glass.

  • Snake and spider phobias may be especially prevalent due to preparedness.

    • People associate shock with spiders or snakes more readily than with flowers or mushrooms.


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