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Animal Research

Animal Research. Problem of Variability of human participants Use Animals to increase control Rearing - littermates Genetics – littermates, inbred strains Experience- what they were exposed to Environmental conditions – food, water, lighting, temperature, cage size, etc. Use of animals.

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Animal Research

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  1. Animal Research • Problem of Variability of human participants • Use Animals to increase control • Rearing - littermates • Genetics – littermates, inbred strains • Experience- what they were exposed to • Environmental conditions – food, water, lighting, temperature, cage size, etc.

  2. Use of animals • To reduce variability • To study basic processes • To study special variables that can’t be tested in humans – e.g. brain function • To learn more about animals

  3. Research Designs • Random Groups • Split litter (Matched groups) • Within subjects • Mixed designs • Small N design (ABA design) • Classical Conditioning • Instrumental Conditioning • Ethological methods

  4. Classical Conditioning • Pavlov • Digestion • Salivation • Dogs • Inappropriate salivation • Psychic secretions • UCS, UCR, CS, CR, contiguity

  5. Classical Conditioning of drug related stimuli • UCS = morphine • UCR = Heart rate decrease • CS = drug stimuli • CR = ??

  6. CR = heart rate up! • Compensatory response

  7. Drug Overdose • CS is different • UCS = same as before • CR = no compensatory response • Heart rate too low – person dies

  8. Contiguity Theory • Pavlov’s explanation • Two events that occur closely together will become associated • Temporal contiguity • Spatial contiguity

  9. Methods in Classical Conditioning • Tests of Contiguity theory • CS – UCS temporal relationships • Square wave diagram • Simultaneous conditioning • results • Delayed conditioning • Short – delay • Long - delay • Trace conditioning • Short – delay • Long - delay • Backward conditioning

  10. Inhibitory Classical Conditioning • Excitatory classical Conditioning • A CR is produced • Inhibitory classical conditioning • A CR is inhibited • Must first have excitatory to demonstrate inhibitory • Pop quiz example

  11. Higher – Order conditioning • Diagram • Sequence of CSs • Waterfall example

  12. Sensory Preconditioning • Pair two stimuli for several trials • Use one as a CS until you get CRs • Test other stimulus • Do you get a CR to second stimulus?

  13. Yes • Pairing stimuli before training in some way makes them equivalent • Evidence for S – S association in classical conditioning • CS – UCS association produces conditioning

  14. Other methods: Preexposure • CS pre-exposure • Present CS alone for several trials (16-20trials) • Pair CS with UCS in excitatory conditoning • Test for CR • UCS pre-exposure • Present UCS alone for several trials • Pair UCS with a CS • Test for CR

  15. Measuring the CR • Determining if CR occurs • Omit the UCS • See if CR occurs • Problem: Extinction occurs • Probe trials • See if CR occurs on probe trial only (e.g. 1/15) • Measuring Strength of CR • Frequency –e.g. 7/10 probe trials • Latency – e.g. number second to produce CR • Magnitude – e.g. number of drops of saliva

  16. Discrimination • A tool to measure other behaviors • Pavlov – discrimination of shape by dogs • CS+ paired with ucs = CR • CS- not paired with ucs = no CR • Experimental neurosis • CS+ = circle • CS- = ellipse (9:1) • Dogs became neurotic

  17. Generalization • A tool to study other behaviors • Train on one CS (e.g. cs = red) • Test on new CS’s (orange, bluish red, etc) • The more similar the new CS’s the more generalization that occurs • Generalizaton gradient • Training one stimulus trains a whole host of stimuli

  18. Extinction • As a tool to measure the strength of CR • Present CS without UCS • CR dies out or extinguishes • Pavlov – extinction involves the active withholding of the CR • Spontaneous recovery • Faster relearning

  19. Instrumental Conditioning • Instrumental/Operant =The consequences of a response change the future probability of the response • Classical vs Instrumental • Subject passive subject active • Stimuli imposed stimuli unknown • Behavior elicited Behavior emitted • S – S; S – R R – S • Autonomic mainly skeletal mainly

  20. Pre-training Procedures • Deprivation • 85-90% body weight • Weigh dailey • Calculate food amounts • Handling • Sampling the reinforcer • Adaptation to apparatus • Magazine training

  21. Pre-training (Cont.) • Measure operant level • Shaping • Autoshaping • Successive approximation • Now ready to start experiment

  22. Instrumental Designs • Free Operant (Skinner) • Operant chamber • Animal free to make response at any time • DV = rate of responding (responses/unit time) • Cumulative responses • Cumulative recorder • Interpret graphs of data • Small-n design

  23. Discrete Trial • Response can only occur at a time specified by the researcher (Thorndike and others) • Many possible DVs • Latency – straight alley, Morris water maze • Speed of response – straight alley • Choice – T-maze • Percent correct – Stone maze, WGTA • Errors – complex maze

  24. Reinforcement • A reinforcer is any thing (stimulus) that increases the probability of the response that it follows. • Must make sure that a stimulus actually is a reinforcer first before using it to change behavior • E.g “gold stars”

  25. Types of Reinforcement • Positive Reinforcement • A response, followed by the presentation of a reinforcing stimulus, increases the future probability of the response. • A hungry rat presses a lever to get food • Mom gives junior a cookie for picking up his toys

  26. Negative Reinforcement • Also called “escape training” • A response, followed by the withdrawal of the reinforcing stimulus, increases the future probability of the response • A rat jumps a low hurdle and a loud noise is turned off • A person, stopped at a red light, rolls up the car window to decrease the sound of a jack hammer working on the concrete curb

  27. Punishment • A punisher is any thing (stimulus) that decreases the probability of the response that it follows. • Must check to see that a stimulus is a punisher • E.g. tantrums

  28. Types of Punishment • Punishment by presentation • A response, followed by the presentation of a punishing stimulus, becomes less probable in the future • A rat, steps off a pedestle and gets shocked • Johnny hits his sister and gets spanked by dad • (What’s Johnny learning here?)

  29. Punishment by withdrawal • Also called “ omission training” • A response, followed by the withdrawal of a positive reinforcer, decreases the future probability of the response • A rat, presses a lever, and as a result, loses access to food for 60 seconds • Johnny hits his sister, and as a result, doesn’t get to watch his favorite violent cartoon show

  30. Categories of Reinforcement • Primary • Unlearned • Physiological • Food • Water • Sex • Pain

  31. Categories of Reinforcement • Secondary/Conditioned • Learned • Neutral initially • Paired with a primary reinforcer • Tokens/token economies • Chimps • Strip mines

  32. Categories of Reinforcement Social Attention Affection Praise Trans-situational Paired with several reinforcers Money

  33. Schedules of Reinforcement • Simple Schedules (only one requirement for reinforcement) • Ratio Schedules (responses) • Fixed Ratio • Variable Ratio • Interval Schedules (time) • Fixed Interval • Variable Interval

  34. Ratio Schedules • Fixed Ratio (e.g. FR10) • Number of responses per reinforcement is fixed and unchanging • No reinforcement for responses until the ratio is completed: last response produces reinforcer • In well trained subjects: • Ratio is run off all at once • Post-reinforcement pause • E.g. piece work

  35. Variable Ratio • Variable Ratio (VR10) • Number of responses required is constantly changing from one reinforcement to the next • Unpredictable • Best strategy: • Work fast • Work consistently • E.g. gambling

  36. Interval Schedules • Fixed Interval (FI60) • Amount of time that must pass between reinforcements is fixed. • Predictable • Best strategy: • Wait until appropriate amount of time has passed • Scallop shaped records • E.g. test dates

  37. Variable Interval • Variable Interval (VI60) • Amount of time that must pass between reinforcements is constantly changing • Unpredictable • Best strategy: • Work consistently • E.g. pop quizzes • A tool for studying other behaviors

  38. Complex Schedules • More than one requirement must be met • Often used as tools to study other aspects of research • DRL • Progressive ratio

  39. Discrimination • Differential responding to stimuli • Sd – sets occasion for reinforcement • S-delta – sets occasion for non-reinforcement • As in classical conditioning, discrimination can be used as a tool to study other behaviors • E.g. recognition memory in monkeys using DNMS

  40. Generalization • Same as in classical conditioning • Can be used to study other behaviors • Reinforce behavior in presence of one stimulus, look at how the behavior generalizes to other similar stimuli • E.g. taking notes in biology class – taking notes in psychology class.

  41. Extinction • Also like classical conditioning • Used to study other behaviors • E.g. preference for a reinforced location in the Morris water maze. • Study annulus crossings during extinction

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