Domjan Chapter 3 - Classical Conditioning PDF

Domjan Chapter 3 Classical Conditioning: Foundations  Chapter 3: Outline The Early Years of Classical Conditioning – Pavlov – The Classical Conditioning Paradigm Functional examples Experimental Situations – Fear conditioning – Eyebl...

Domjan Chapter 3 Classical Conditioning: Foundations  Chapter 3: Outline The Early Years of Classical Conditioning – Pavlov – The Classical Conditioning Paradigm Functional examples Experimental Situations – Fear conditioning – Eyeblink conditioning – Sign tracking & goal tracking – Taste preferences & aversions Excitatory Pavlovian Conditioning Methods Inhibitory Pavlovian Conditioning Prevalence of Classical Conditioning Chapter 3: Foundations of Classical Conditioning  The world is a complex place… Habituation & sensitization deal with learning about one stimulus Certain events occur together Learning to predict events in the environment help us to effectively interact with our environment  Classical Conditioning Learning about relationships between two events Allows animal to predict or anticipate e.g., Where to find food, shelter Making a response Activating behaviour (excitatory association) NOT making a response Inhibiting excitatory associations Not looking for food when there is a predator present Behavioral System Paradigm- based on Hogan 1988 All potential sensory All potential motor outputs of an inputs of an organism organism- including motor input (which could also be considered a sensory input) Sensory Motor Stimuli 1 output 1 Central Sensory Motor mechanism( Stimuli 2 output 2 s) Sensory Motor Stimuli 3 output 3 Behavioral System Paradigm- based on Hogan 1988 Sensory Motor Stimuli 1 output 1 Central Sensory Motor mechanism( Stimuli 2 output 2 s) Sensory Motor Stimuli 3 output 3 Historical antecedents of modern learning: Part 2 (review of) Descartes & Reflexes Assumed reflexes were responsible for only simple reactions to stimuli Considered actions to be fixed He thought input = output Two Russian physiologists (1) Ivan Sechenov (1829-1905) Stimuli as releasers Input ≠ Output (e.g. small stimulus, big response) Explained voluntary thoughts and behaviour as elicited by inconspicuous or faint stimuli Did not address how experience can alter behaviour Two Russian physiologists (2) Ivan Pavlov (1849-1936) Nervism: all key physiological functions are controlled by the nervous System S-R unit (stimulus-response) associations Study behaviour to understand nervous system New reflexes can be learned through association Field of Functional Neurology Studied digestion and reflexes in dogs Pavlov’s Team: Vul’fson & Snarskii Object learning: learning associations between different stimulus elements of an object Not able to independently manipulate stimuli o e.g. taste, texture, sight Cannot study mechanisms This lead Pavlov to use stimuli from different objects  Classical Conditioning Paradigm: Terms and general methodology (1) BEFORE CONDITIONING Unconditioned stimulus (US): environmental trigger (e.g. meat) Unconditioned response (UR): response to the US (e.g. salivation) No need for prior training  Classical Conditioning Paradigm: Terms and general methodology (1) BEFORE CONDITIONING Conditioned stimulus (CS): stimulus that precedes or signals the unconditional stimulus (e.g. tone) Stimulus that becomes the CS must be initially neutral (i.e. BEFORE training, the stimulus does not produce responding)  Classical Conditioning Paradigm: Terms and general methodology (2) DURING CONDITIONING CS (tone) and US (food) presented together, result in the UR  Classical Conditioning Paradigm: Terms and general methodology (3) AFTER CONDITIONING Conditioned response (CR): response that comes to be elicited from the CS (e.g. salivation after conditioning)  Types of Conditioning Research Classical Conditioning research can be dichotomized into two schools of thought: 1. Study the cause or mechanisms of conditioning (most laboratory studies) 2. Directly study functional outcomes or implications of classical conditioning Functional Example #1: Reproductive Success Hollis et al. (1997) investigated male aggressive behaviour in relation to mating success blue gourami (fish) Classically conditioned males to anticipate the arrival of a female These males had more reproductive success than did control males First evidence of reproductive benefits from classical conditioning  Functional Example #1: Reproductive Success Hollis et al. (1997) methods Subject: Male blue gourami Training: One trial per day Learning Group (PAV): 10-s presentation light (CS) →(followed by) 5-min exposure to female (US) Control Group (UNP): 10-s presentation light / (independent of) 5-min exposure to female Test: After 18 days of training Both PAV and UNP: 10-s presentation light (CS) → 5-min exposure to female (US) Male and female allowed to interact for 6 days and behaviour recorded Hollis et al. (1997) J. Comp. Psychol. Functional Example #1: Reproductive Success Hollis et al. (1997) results UNP males acted more aggressively towards females (bites), compared to PAV males PAV males performed more nest- building behaviour, compared to UNP males Hollis et al. (1997) J. Comp. Psychol. Functional Example #1: Reproductive Success Hollis et al. (1997) results, cont. Classically conditioned fish had higher reproductive success! PAV males PAV males PAV males had more spawned had more fry clasps more quickly Hollis et al. (1997) J. Comp. Psychol.  Functional Examples (1) Hollis et al. (1997) used a “classic” Classical Conditioning design (2) Dukas & Bernays (2000) used an associative learning paradigm to test for functional outcomes Extension of classical conditioning How to extend ideas covered in Psych 381 Functional Example #2: Improved Growth Rate Dukas & Bernays (2000) Subjects: Grasshoppers Each cage contained two food dishes: (1) Balanced diet (2) Deficient diet Each dish paired (associated) with color, location & odor Dukas & Bernays (2000) PNAS, from Dugatkin (2009) Functional Example #2: Improved Growth Rate Dukas & Bernays (2000) methods Training: Dishes changed mid-day LRN: All cues (location, color, odor) always consistent RAN: Location, color & odor all random b = balanced diet d = deficient diet cit & co = odours Dukas & Bernays (2000) PNAS, from Dugatkin (2009) Functional Example #2: Improved Growth Rate Dukas & Bernays (2000) results Learning grasshoppers Learning grasshoppers visited the better quality spent more time eating food more often the better quality food Dukas & Bernays (2000) PNAS, from Dugatkin (2009) Functional Example #2: Improved Growth Rate Dukas & Bernays (2000) results, cont. The grasshoppers in the group that was allowed to form associations benefited by growing more quickly than grasshoppers that were not able to learn associations between the different stimuli Growth rate positively correlated with eggs size and number Dukas & Bernays (2000) PNAS, from Dugatkin (2009)  Summary: Types of Conditioning Research Classical Conditioning research can be dichotomized into two schools of thought: 1. Study the cause or mechanisms of conditioning (most laboratory studies – more to come in Chapter 4 of Domjan) 2. Directly study functional outcomes or implications of classical conditioning Classical Conditioning: Experimental Paradigms Four classic examples “Classic” Experimental paradigms Fear conditioning Eyeblink conditioning Sign tracking & goal tracking Taste aversion learning  “Classic” Conditioning Paradigms Fear conditioning  Classical Conditioning: Fear Conditioning Fears are learned, like other behaviors Why is this different? o Fear is a ‘complex’ response  Phobias in Humans Initial trauma (US+UR) led to “irrational” fear to otherwise neutral stimulus (CS+CR)  Fear Conditioning in Humans Started with Watson and Rayner (1920) Classical conditioning of emotional responses “Little Albert” study Video: https://www.youtube.com/watch?v=5duLMjaTL0U  Fear Conditioning in non-humans CS (e.g. tone) is paired with an aversive US (e.g. shock) How to measure fear (different in different species) o Measure indirectly o Rats - Freezing: evolved adaptive defensive response  Assessing fear with suppression ratio in lever pressing behaviour Suppression ratio = CS behaviour/ (CS behaviour + pre-CS behaviour) o Values range from 0 (full suppression) to 0.5 (no suppression) o Smaller values mean more fear because behaviour is disrupted more Video: https://www.youtube.com/watch?v=ZlZekx1P1g4 Note: animal is already trained to perform some behaviour (e.g. lever pressing, licking water bottle)  Conditioned suppression in rats: Lick suppression example (1) Thirsty rats, (2) Fear conditioning (3) Test: Drinking during measure how tone (CS) much it drinks LRN group: tone CS behaviour: (CS) terminates in 5 licks shock Suppression ratio = 5/(5+50) = 0.09 Pre-CS CS behaviour: CTL group: tone behaviour: 48 licks and shock unpaired 50 licks Suppression ratio = 48/(48+50) = 0.49  “Classic” Conditioning Paradigms Fear conditioning Eyeblink conditioning  Classical Conditioning: Eyeblink Conditioning Condition the eyeblink reflex Pair CS (e.g. tone) with US (e.g. puff of air to eye OR electrical current just under eye) Rabbits: good model species because they rarely blink in the Gormezano, 1966 absence of a stimulus Eyeblink Conditioning  “Classic” Conditioning Paradigms Fear conditioning Eyeblink conditioning Sign tracking  Classical Conditioning: Sign Tracking (also called autoshaping) Brown and Jenkins (1968) o Pigeon in operant chamber o Light illuminated before food delivery o Pigeons pecked at light – (FOOD WOULD ARRIVE WITHOUT PECKING!) o Video: https://www.youtube.com/watch?v=cacwAvgg8EA In nature, animals need to approach food before they are able to consume it  Classical Conditioning: Sign Tracking (also called autoshaping) Approaching a CS that signals food o Even when spatially distant from food delivery Long Box video: https://www.youtube.com/watch?v =KnJPPaiJG6Y Domjan (2006) o CS must be localized (to be approached and tracked) e.g. tone CS does not work!  Sign tracking Goal tracking Individual Differences CS = presentation of lever US = food Trial: Insert lever (8s), then withdraw lever & give food Flagel et al., 2009; Domjan, 2015  “Classic” Conditioning Paradigms Fear conditioning Eyeblink conditioning Sign tracking Taste-aversion learning  Classical Conditioning: Taste conditioning Taste-aversions (and preferences) are learned Unique feature #1: Aversions can be learned in a single trial! Alcock (2005)  Effects of CS-US interval on CTA Unique feature #2: Aversion occurs even if the negative outcome (US) is delayed by several hours Rats given saccharin flavoured water, then made sick (x-ray) at different time points, or not (sham) Tested for preference of saccharin flavoured versus regular water a day later Smith & Roll, from Domjan (2010)  Classical Conditioning: Taste conditioning Human taste-aversions are Pavlovian, too (e.g. chemotherapy-induced nausea) Taste preferences can also be conditioned o Evaluative conditioning: neutral stimulus gain favour through association with something that is already liked (or loose favour via association with something you already dislike)  Taste Aversion & Conservation Yellow-spotted monitors (goannas)-2016 Trained with juvenile cane toads  Points to Ponder 1. Many paradigms used to investigate Classical Conditioning 2. Classical Conditioning is used as a starting point for experiments that use associative learning in a broad sense 3. Classical Conditioning is involved in important aspects of behaviour, not just in the laboratory Types of Classical Conditioning Excitatory and Inhibitory conditioning  Classical Conditioning: Excitatory Conditioning Procedures CS paired with a US (i.e. CS occurs, then US occurs) Following repeated pairings, presentation of the CS alone leads to behaviour previously associated only with the US o From previous examples: Hollis et al. (2007), light = readiness to mate Watson & Rayner (1920), rat = crying and escape behaviour General eyeblink procedure, tone = eyeblink Prototype Conditioning Trial:  Prototype Conditioning Trial: Conditioning trial – Each CS-US paring Trial  Prototype Conditioning Trial: Intertrial interval (ITI) – Time from the end of one trial to the start of the next trial Time Intertrial interval  Prototype Conditioning Trial: Interstimulus interval (ISI) – Time from the start of the CS until the start of the US CS-US Interval Classical Conditioning: Five Common Procedures Domjan (2010)  To consider: – Backward conditioning Why/when would this work? – Predator may not be noticed until after it has attacked prey animal – But that does not mean that the prey will not benefit to learn something about the predator  Timing is everything: ISI and strength of conditioning Short delay conditioning is usually the most effective! Domjan (2010)  Effectiveness Temporal Coding Hypothesis: Pavlovian conditioning procedures lead not only to learning that the US happens, but exactly when it occurs in relation to the CS US occurred 150 ms after onset of CS US occurred 500 ms after onset of CS 20 trials each Domjan, 2015 Behavioral System Paradigm- based on Hogan 1988 Motor US output 1 Central Motor CS mechanism( output 2 s) Motor Time? output 3  What makes for strong associations? Contiguity: Events are close together in time and space Contingency: One event is perceived as causing another Ecological/biological relevance: Events have ‘natural’ connection, have been linked in evolutionary history How do we know if learning has occurred? Test trial(s): present the CS (tone) without the US (food) Compare behaviour between two groups o One group experiences learning condition o Other group experiences control condition o How does the animal behave (CR)? Magnitude of the CR Probability of CR occurring (over multiple test trials) Latency until CR occurs  Control in Classical Conditioning What do we have to control for? o Pseudo-conditioning How can we control? o Present CS but unpaired with US Random: CS and US are presented at times that are random with respect to one another Explicitly unpaired: CS and US are presented with sufficient time between them so that they do not become associated with each other  Classical Conditioning: Inhibitory conditioning Learning to predict the absence of the US o Predictable aversive events are better than unpredictable aversive events o It also allows you to predict when bad things will not happen Conditioned inhibitor: signal for the absence of the US  Classical Conditioning: Excitatory & Inhibitory Conditioning Excitatory conditioning is the learning of a relationship between the presence of the CS and the subsequent presentation of the US Inhibitory conditioning is learning to predict the absence of a US Does not necessarily have anything to do with punishment or aversive stimuli  For inhibitory Conditioning: The US must already occur sometimes For the removal or absence of the US following the presence of the inhibitory CS (the CS-) to be meaningful (and hence, for this association to be learned) the US must occur (or be expected to occur) in the context where the reaction to its absence (following a CS-) is tested  Conditioned Inhibition Procedure: Two types Pavlovian Negative CS-US Contingency  Standard Conditioned Inhibition Procedure (Pavlovian Procedure) 1. Excitatory context created by CS+ (Trial A)Presentation of CS+ with CS- results in no US (Trial B) 2. Trials are intermixed in training 3. CS- acquires inhibitory properties Domjan (2010)  Inhibitory Procedure: Negative CS-US Contingency No CS+ US occurs, but never just after the CS- CS- signals reduction in probability that US will occur How do you quantify inhibitory conditioning? 1. Bidirectional response systems 2. Compound-stimulus or summation test 3. Retardation-of-acquisition test  How do we know if learning has occurred for inhibitory conditioning? Bi-directional Response Systems o Measure increase (conditioned excitation) or decrease (conditioned inhibition) from a known baseline Moving towards or away from something, drinking or eating more or less o Does not work for all behavioural systems Freezing behaviours, eyeblink – The opposite of fear (freezing) is not more behavior but baseline How do you quantify inhibitory conditioning? 1. Bidirectional response systems 2. Compound-stimulus or summation test 3. Retardation-of-acquisition test  How do we know if learning has occurred for inhibitory conditioning? Compound-Stimulus (Summation Test) o Conditioned inhibition counteracts conditioned excitation Therefore: Presence of CS- should affect responding  Compound-Stimulus (Summation Test) Training: Thirsty rats drinking water, measured how long until they drank continuously for 5 seconds B & X were never A+ = shock presented together B+ = shock (in another chamber) during training! AX- = no shock X became a general safety cue! Testing: with stimulus pairs that were trained, and novel stimulus pairs, and a novel stimulus (Y) Cole et al. 1997, from Domjan (2010) How do you quantify inhibitory conditioning? 1. Bidirectional response systems 2. Compound-stimulus or summation test 3. Retardation-of-acquisition test Retardation of Acquisition Test: Turning a previous CS- into a CS+ Previous conditioning history: o X previously conditioned as CS- (no shock) o Y had no previous training Cole et al. 1997, from Domjan (2010) Training: Paired both with shock Test: To see the conditioned suppression of drinking Classical Conditioning: It’s everywhere!