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:
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…)
Ivan Petrovich Pavlov (1849-1936) Pavlovian (Classical) conditioning Physiologist Digestion Dogs Conditional redirection of reflexes Conditional reflexes
Conditional?? Yes, conditional Mistranslated to conditioned For learning at least, this is where the term “conditioning” came from
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
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
The Basics TIME Conditional Stimulus on off Unconditional Stimulus on off Unconditional Response (after enough pairings) Conditional Response
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
Probe (Test) Trials TIME Conditional Stimulus on off Unconditional Stimulus on off No Unconditional Response without the US! Conditional Response?
Some notes & examples… Awareness is NOT necessary Eyeblink Conditioned Suppression (Conditioned Emotional Response) Suppression ratios Another way of MEASURING conditioning Taste Aversion Tequila?
S-S or S-R? US CS Response What kind of connection is being made?
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
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
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)
Factors that affect conditioning Contiguity Contingency Stimulus Features Prior Experience Number of Pairings Intertrial Interval
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!
Group CS-US pairings US aloneCR strength A.400Very strong B.40.10strong C.40.20Medium D.40 weak
Contingency If-then situation Consistency of pairing CS and US Greater contingency, greater learning informative
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?
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
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)
Number of Pairings Acquisition curve Non-linear Asymptote Conditioning Trials CR Strength asymptote
Intertrial Interval ITI Time between each CS-US pairing (i.e., between trials) Generally, around 30 seconds effective
Extinction, Spontaneous Recovery and Reacquisition
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
Spontaneous Recovery After extinction, let time pass Present CS again (no US) Temporary, small return of CR Shows extinction is not forgetting!!