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Facebook Group: The group is called: Psych281 Spring08 Available only to University of Alberta network Sorry to be rude but… Please don’t add me as a friend.

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Presentation on theme: "Facebook Group: The group is called: Psych281 Spring08 Available only to University of Alberta network Sorry to be rude but… Please don’t add me as a friend."— Presentation transcript:

1 Facebook Group: The group is called: Psych281 Spring08 Available only to University of Alberta network Sorry to be rude but… Please don’t add me as a friend (avoiding any kind of favoritism, etc…)

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3 Ivan Petrovich Pavlov ( ) Pavlovian (Classical) conditioning Physiologist Digestion Dogs Conditional redirection of reflexes  Conditional reflexes

4 Conditional?? Yes, conditional Mistranslated to conditioned For learning at least, this is where the term “conditioning” came from

5 Terminology Unconditional stimulus (US) Stimulus that elicits the innate reflex (e.g., food) Unconditional response (UR) Reflex action that occurs in response to US (e.g., salivation) Conditional stimulus (CS) Any stimulus that doesn’t originally elicit the UR (e.g., buzzer) Conditional response (CR) The action elicited by the CS (e.g., salivation) THIS IS LEARNED

6 The Basics Use behaviours that are already in place – Reflexes Associate some new (neutral) stimulus with the stimulus that evokes the reflex How? Present them together! Buzzer-food (salivate) Buzzer-? - CS-US  UR - CS-US  (CR) UR - CS  CR

7 The Basics TIME Conditional Stimulus on off Unconditional Stimulus on off Unconditional Response (after enough pairings) Conditional Response

8 Measuring Conditioning Sometimes difficult to measure CR e.g., if CS & US close together, CR & UR can overlap Buzzer-food-saliva, buzzer-saliva-food? How long is the separation between the buzzer and the food? Intensity Does CR intensity increase with experience? Test trial (probe trial) Give CS alone

9 Probe (Test) Trials TIME Conditional Stimulus on off Unconditional Stimulus on off No Unconditional Response without the US! Conditional Response?

10 Some notes & examples… Awareness is NOT necessary Eyeblink Conditioned Suppression (Conditioned Emotional Response) Suppression ratios Another way of MEASURING conditioning Taste Aversion Tequila?

11 S-S or S-R? US CS Response What kind of connection is being made?

12 Rescorla (1973) So, how do you get rid of a response that is hard wired to a stimulus? How can you get rid of a reflex? Habituation

13 Results Less suppression in Habituation group (In other words, more responding) Therefore, the connection MUST be S – S Group Phase 1 Phase 2 Test Habituation L  N (startle) Noise (habituate) Light Control L  N (startle) NothingLight

14 Higher Order Conditioning S-S-S? CSs and USs can be associated (First-order) CSs can be associated with other CSs Second-order conditioning salivation (CR) first-order CS tone (CS1)food (US) second-order CS Light (CS2)

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16 Types of Conditioning Delay Short Long Trace Simultaneous Backwards Inhibitory

17 Delay Conditioning CS and US overlap Short Usually the most effective Long timing

18 Trace Condition From “memory trace” Must remember CS Other stimuli interfere CS US GAP

19 Simultaneous conditioning Weaker than short delay CS can’t signal onset of US Not predictive CS US

20 Backwards conditioning Much more difficult Ignores order CS US

21 Conditioned Inhibition CS- Up until now, we’ve been talking about CS+ CS signals the ABSENSE or NON-OCCURRENCE of US Needs to be some expectation of the US for this to work CS+ US CS-

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23 Factors that affect conditioning Contiguity Contingency Stimulus Features Prior Experience Number of Pairings Intertrial Interval

24 Contiguity Closeness together in time and/or space Usually, more learning if greater contiguity between CS & US Type of conditioning may influence this e.g., eyeblink vs. taste aversion BUT, contiguity is not sufficient!

25 Group CS-US pairings US aloneCR strength A.400Very strong B.40.10strong C.40.20Medium D.40 weak

26 Contingency If-then situation Consistency of pairing CS and US Greater contingency, greater learning informative

27 Stimulus Features Intensity of stimuli (CS & US) Compound Stimuli Two+ simple CSs presented at the same time Paired with US Overshadowing – if one CS is more salient, the other CS may be ignored Nature of Stimuli (relevance or belongingness) Loud & noisy water?

28 Prior experience Prior experience with CS and/or US affects conditioning contingency Latent inhibition Prior experience with an neutral stimulus makes it harder for it to become a CS later Novelty Blocking Introducing a new CS (CS2) in compound with an already trained CS (CS1) CS2 won’t be learned about

29 Sensory preconditioning Pair two CSs Pair one with a US Unpaired CS still elicits CR Phase 1 (CS1+CS2): -Light + Tone Phase 2 (CS1+US): -Light + Food Test (CS2?) -Tone? (measure response)

30 Number of Pairings Acquisition curve Non-linear Asymptote Conditioning Trials CR Strength asymptote

31 Intertrial Interval ITI Time between each CS-US pairing (i.e., between trials) Generally, around 30 seconds effective

32 Extinction, Spontaneous Recovery and Reacquisition

33 Extinction Continued pairing of CS with US maintains CR CS without US --> Extinction Weakening and stopping of CR Not forgetting A type of conditioning Withhold responding CS paired with absence of US

34 Spontaneous Recovery After extinction, let time pass Present CS again (no US) Temporary, small return of CR Shows extinction is not forgetting!!

35 Reacquisition Extinguish CR Recondition with CS-US pairing Fewer trials required

36 All Together Now! Trials/Time Strength of CR AcquisitionExtinction Spontaneous Recovery Reacquisition CS&USCS alone CS&US

37 How does this all work?

38 Stimulus Substitution Theory Pavlov CR and UR produced by same neural region Response center CS takes on properties of US Substitution US center CS center Response center

39 Sign Tracking Food

40 Sign Tracking

41 But… CR should be the same as UR e.g. signtracking, autoshaping But it’s NOT!! Intensity, magnitudes Omissions & additions Different CSs elicit different CRs Compensatory responses

42 Preparatory Response Theory Learn responses that prepare organism for US occurrence Sometimes CR same as UR, sometimes different Drug Tolerance


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