Classical Conditioning Foundations: o Classical ...
Classical Conditioning Foundations: o Classical Pavlovian conditioning is the simplest mechanism by which an organism learns about relations between stimuli o Animals come to make new responses to stimuli based on learning about orderly sequences of events in the environment o Pavlov and Twitmyer independently discovered classical conditioning, Twitmyer however failed to develop the implications of his findings, Pavlov undertook an extensive program of research on conditioning o The first systematic studies of classical conditioning in Pavlov’s lab by Vul’fson an Snarskii Classical Conditioning Basic Terms: o Unconditioned stimulus (US): elicits relevant responses (UR) without prior training (without training, a thirsty animal will drink) o Unconditional response (UR): response to the US (eating when presented food), predictable thing animals do when given the opportunity o Conditioned stimulus (CS): one that you are trying to teach the animal/person to react to (teaching dogs to salivate when they hear a bell), depends on prior training to elicit relevant responses (CR) o Conditioned response (CR): the response to the CS (salivating when they hear a bell even with no food present) o UR is salivating to food, CR is salivating to the bell (salivation is the same, stimulus is different) Myths About Classical Conditioning: o Simple and primitive form of learning involving only glandular and visceral responses live salivation o CSUS associations occur automatically through the pairing of a CS and US o Has no relevance in explaining the complexity and richness of animal and human experience Modern View of Classical Conditioning: o Involved numerous complex processes that control a wide variety of responses including locomotor movements and emotional behaviour o Ex. little girl and her father every time they went over a bridge, he would say we are going to die, UR would be that she would freak out, she developed a phobia of bridges as she associated the UR fear of her father panicking with the bridge and now her CR is fear to the bridge which was previously associated with her father panicking (the UR) o It does not occur automatically with the pairing of a CS and US, it depends on the prior experience with these stimuli, the presence of other stimuli during conditioning and the relevance of the CS and US to each other Fear Conditioning: o Little Albert:
• Initially did not fear the rat but hated loud noises • The rat would be introduced with a loud noise which made Albert cry • Albert learned to fear rats and generalize thus fear other furry things • Associate the loud bang (US) with the rat o Fear conditioning happens very quickly (animals learn quickly that something is going to hurt them) o Fear conditioning is used to try to understand the way conditioned responses and conditioned stimuli work together Conditioned Suppression: o Trying to suppress an activity o Trying to teach an animal to not do something they usually do o Ex. you see how much water a thirsty rat and we measure the amount of water the rat drinks and look at how much time it takes for them to drink that same amount of water after we have tried to suppress the behaviour (may associate a shock with a light and then flash the light when they are thirsty with water available and see how much longer it takes them to drink the water) o Animals are taught to stop moving and freeze when they are scared (unconditioned response to fear is to freeze) o Teach an animal that they will get food from a level and that they will get a shock, when they get a shock they freeze o There is a white noise during shock conditioning trial, can see fairly quickly the animal learns to freeze to the white noise (CS) Experimental Procedures: (watch videos on mls) o Eye blink conditioning in humans (reflex arc when a puff of air is directed to your eye) • US (puff of air or weak electric current) • CS (light, tone or mild vibration) • Demonstrates that the CS and US must be paired in time • Need the light and air to be simultaneous • Have two groups of 5month old infants, one group where they are getting the puff of air and tone but are never paired, for the other group the two are paired (when they are paired, in the second session there is a jump) o Sign tracking: • Begin to track signals, not on purpose • Pigeons study: US of food and UR pecking at the food, light goes on, food appears and the bird eats it, animal learns that when the light is on food comes, start pecking at the light before the food (CR), pigeons start learning to peck at the light to get the food (which is not true, false association) o Spatial proximity of CS and US: • Superstition of sports players not changing their socks when they are on a good run • Associate the socks with doing well
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In the natural environment, cues apparent at a distance can signal food availability • Started moving the light further away from the food and the animal and they continued to run over to peck at the light even if that means they lose some eating time (will still peck at the far away light even when food is already out) • Animals tend to approach and contact these cues that bring them in contact with the food • Sign tracking occurs even when approaching the CS decreases access to the US • When rats had a lever and a food bin, some pulled the lever trying to get food (sign tracking) while some waiting at the food bin for food to come out (goal tracking) o Taste aversion learning: • Aka poison avoidance learning • If you eat something and later you get really sick, you think maybe its because of what you ate (the brain associates that food with being sick and you will never eat that food again) • When a control group is presented with a choice between water and saccharin, about 85%95% of total consumption is saccharin (sweet water) • Make the rats sick (US) and flavoured solution like saccharin (CS) • If we pair saccharin with being sick, in onetrial, their consumption of saccharin goes down to 10% • The fastest learning we now because it is a matter of life or death (your biological self wants to live and stays away from what makes you sick) Questions: o A hungry rat is exposed to a red light, followed by brief access to food. After several such trials, the rat approaches the light bulb when it is illuminated. In this example, the light is __. Conditional stimulus o Which of the following is not true of sign tracking? Sign tracking appears to be limited to rodent species • True: the subject need not do anything to receive the US, sign tracking can occur even if the CS and US delivery area are separated by distance, individual differences in sign tracking correlate with factors associated with drug abuse o Surveys of ** (check text) human eating behaviour suggest which of the following? Even if you are certain that a food did not cause your illness, you may develop an aversion to the taste of that food Excitatory Pavlovian Conditioning: o An association is learned between the CS and the US o Excitatory: the CS comes to predict the occurrence of the US and as a result the CS elicits responses (CRs) that are related to the US o Dog salivated to a ton; USfood
o Pigeon pecks key light; USfood, CRpecking at the light o Rats freeze to a tone; USshock o Rats avoid a flavour; USillness Terminology: o CS, CR, US, UR o CSUS interval (interstimulus interval: between start of CS and the start of the US; start of the bell and start of the food being presented) o Intertribal interval (ITI: interval between end of one conditioning trial and the start of the next trial; may offer tone and shock and then wait 5 minutes and then again tone and shock) o Conditioning trial o Training session: 10 trials in the morning, 10 trials in the afternoon Effectiveness of Common Pavlovian Conditioning Procedures: o Short delayed: short break between the US and the CS (most effective in many situations) o Trace conditioning: have the CS end before the US begins (less effective than delayed and it can result in inhibition of the CR) o Long delayed conditioning: long delay between the CS and US; light is on for a long time before the food is presented (usually not effective and it can result in inhibition of delay) o Simultaneous conditioning: both are presented at the same time and end at the same time (ineffective or a failure of performance rather than learning) o Backward conditioning: present he US first and then the CS; present the food and then the light (complex results and poorly understood) o Look at chart on page 73 Measurement of Conditioned Responses: o Various measures of CRs • Magnitude of the CR (number of pecks, magnitude of light or sound) • Probability of CR following the CS (look at the chances of an animal doing something, 70% of the time when the light flashes, the person blinks) • Latency of the CR following CS onset (having several seconds or no seconds between the CR and the CS, stronger learning with shorter latency) o CS must be evaluated without contamination by the US (we think we have taught someone to do something, think you blink because of the tone but may be because you blink a lot, have to assess the CS alone) o CSalone test trials: • Delayed and race trace procedures (inherent); we have the CS on its own for a period of time so we can observe the animal at that time and see if before learning happens it does anything) • Simultaneous and backward conditioning (critical); do not have the CS alone to see what it does by itself, have to have some times with CS presented on its own
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We have to have some sort of control measure
Control Procedures: o Pseudoconditioning (when an US is presented, the animal reacts; if you shock a rat multiple times and then play a loud noise, it jumps, it looks like an association but you have never paired them together) and sensitization effects (the band is so loud that you are sensitized, every time the guitarist jumps around you scream louder) o Ideal control procedure: • Same number and distribution of CS and US events but with CSs and USs arranged so they would not become associated (not close in time or space, even if we think we have found an association, it may be pseudo conditioning) • Random control: can produce associative learning (randomly present shocks, does not depend on the CS, flash of light with a shock, with no shock, shock in the middle of the flash of light), we start to associate even when there are no connections − Explicitly unpaired control (CSs and USs occur in separate sessions), this is regarded as the most successful control procedure Inhibitory Pavlovian Conditioning: o Have stimuli that increase behaviour (ringing of the bell once you have conditioned the association, causes the dog to salivate, can increase it) o Presence of CS signals absence of US: • A stimulus presented tells the animal that something is not going to happen • A kid goes to school and the bully isn’t there tells the kid that he will not be hurt that day • A signal that predicts the absence of an aversive event (like a shock) or an appetitive event (like food) can acquire conditioned inhibitory properties (i.e., can become a conditioned inhibitory stimulus or CS) • Give them a signal that the aversive event will not happen (a substitute teacher comes to class signalling to you that you will not have the test that day) o An inhibitory stimulus elicits a CR is opposite in direction that produced by an excitatory CS (it can suppress the CR elicited by an excitatory CS) o For absence to be significant, the US has to periodically occur in the stiatuion (you still have to have a situation where you flash a light and a shock occurs, if the pain and anxiety goes away, you do not need the light anymore because there is no more shock) o Inhibitory conditioning requires an excitatory context for the particular US being used o Excitatory conditioning doesn’t depend on a special context in the same way o You can teach a rat that the light leads to a shock so every time it sees a light it freezes, you take it out of the box and put it in a room and it sees a light and it will freeze (context doesn’t always matter)
Procedures for Establishing Conditioned Inhibition: o Trial type A: excitatory (CS+ and US); associate flash of light and the shock) o Trial type B: inhibitory (CS+/CS and no US); flash of light and tone and nothing happens o CS presented in excitatory context of CS+ o Have a light and shock, then add C of a tone and then no shock, over the course of time, the animal learns hat the tone and light means no shock Measurement of Conditioned Inhibition: o If an inhibitory CS suppresses the occurrence of the CR how do we measure it? o Bidirectional response systems (heart rate goes up and down) • Possible to directly observe inhibition with some bidirectional response system • If baseline responding is above zero, deflections in both directions from baseline can be detected (ex. sign tracking – approach vs. avoidance) Measurement of Conditioned Inhibition in NonBiDirectional Systems: o Compoundstimulus (summation test) • Present the CS in compound with the CS+ • CS should reduce the size of the CR elicited by the CS+ • Ex. either drinking or not drinking (cannot undrink), measure how much the organism drinks (mL) in a certain amount of time • Stimuli A and B were conditioned as excitatory stimuli by being presented alone with shock (A+ and B+), stimulus X was conditioned as an inhibitor by being presented with stimulus A without shock (AX), stimulus Y was a control stimulus that had not participated in either excitatory or inhibitory conditioning • A was a flashing light, B, X and Y were auditory cues (clicker, white noise etc.) A and AX were tested in the original context o Retardation of acquisition test: • Try and convert the CS to a CS+ • Make a friend that makes you calm and reduce your anxiety (CS) when you are anxious into a friend that increases your anxiety • This should take longer than trying to convert a neutral stimulus into a CS+ Questions: o The interstimulus interval is: the start between the CS and the start of the US o
• Initially did not fear the rat but hated loud noises • The rat would be introduced with a loud noise which made Albert cry • Albert learned to fear rats and generalize thus fear other furry things • Associate the loud bang (US) with the rat o Fear conditioning happens very quickly (animals learn quickly that something is going to hurt them) o Fear conditioning is used to try to understand the way conditioned responses and conditioned stimuli work together Conditioned Suppression: o Trying to suppress an activity o Trying to teach an animal to not do something they usually do o Ex. you see how much water a thirsty rat and we measure the amount of water the rat drinks and look at how much time it takes for them to drink that same amount of water after we have tried to suppress the behaviour (may associate a shock with a light and then flash the light when they are thirsty with water available and see how much longer it takes them to drink the water) o Animals are taught to stop moving and freeze when they are scared (unconditioned response to fear is to freeze) o Teach an animal that they will get food from a level and that they will get a shock, when they get a shock they freeze o There is a white noise during shock conditioning trial, can see fairly quickly the animal learns to freeze to the white noise (CS) Experimental Procedures: (watch videos on mls) o Eye blink conditioning in humans (reflex arc when a puff of air is directed to your eye) • US (puff of air or weak electric current) • CS (light, tone or mild vibration) • Demonstrates that the CS and US must be paired in time • Need the light and air to be simultaneous • Have two groups of 5month old infants, one group where they are getting the puff of air and tone but are never paired, for the other group the two are paired (when they are paired, in the second session there is a jump) o Sign tracking: • Begin to track signals, not on purpose • Pigeons study: US of food and UR pecking at the food, light goes on, food appears and the bird eats it, animal learns that when the light is on food comes, start pecking at the light before the food (CR), pigeons start learning to peck at the light to get the food (which is not true, false association) o Spatial proximity of CS and US: • Superstition of sports players not changing their socks when they are on a good run • Associate the socks with doing well
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In the natural environment, cues apparent at a distance can signal food availability • Started moving the light further away from the food and the animal and they continued to run over to peck at the light even if that means they lose some eating time (will still peck at the far away light even when food is already out) • Animals tend to approach and contact these cues that bring them in contact with the food • Sign tracking occurs even when approaching the CS decreases access to the US • When rats had a lever and a food bin, some pulled the lever trying to get food (sign tracking) while some waiting at the food bin for food to come out (goal tracking) o Taste aversion learning: • Aka poison avoidance learning • If you eat something and later you get really sick, you think maybe its because of what you ate (the brain associates that food with being sick and you will never eat that food again) • When a control group is presented with a choice between water and saccharin, about 85%95% of total consumption is saccharin (sweet water) • Make the rats sick (US) and flavoured solution like saccharin (CS) • If we pair saccharin with being sick, in onetrial, their consumption of saccharin goes down to 10% • The fastest learning we now because it is a matter of life or death (your biological self wants to live and stays away from what makes you sick) Questions: o A hungry rat is exposed to a red light, followed by brief access to food. After several such trials, the rat approaches the light bulb when it is illuminated. In this example, the light is __. Conditional stimulus o Which of the following is not true of sign tracking? Sign tracking appears to be limited to rodent species • True: the subject need not do anything to receive the US, sign tracking can occur even if the CS and US delivery area are separated by distance, individual differences in sign tracking correlate with factors associated with drug abuse o Surveys of ** (check text) human eating behaviour suggest which of the following? Even if you are certain that a food did not cause your illness, you may develop an aversion to the taste of that food Excitatory Pavlovian Conditioning: o An association is learned between the CS and the US o Excitatory: the CS comes to predict the occurrence of the US and as a result the CS elicits responses (CRs) that are related to the US o Dog salivated to a ton; USfood
o Pigeon pecks key light; USfood, CRpecking at the light o Rats freeze to a tone; USshock o Rats avoid a flavour; USillness Terminology: o CS, CR, US, UR o CSUS interval (interstimulus interval: between start of CS and the start of the US; start of the bell and start of the food being presented) o Intertribal interval (ITI: interval between end of one conditioning trial and the start of the next trial; may offer tone and shock and then wait 5 minutes and then again tone and shock) o Conditioning trial o Training session: 10 trials in the morning, 10 trials in the afternoon Effectiveness of Common Pavlovian Conditioning Procedures: o Short delayed: short break between the US and the CS (most effective in many situations) o Trace conditioning: have the CS end before the US begins (less effective than delayed and it can result in inhibition of the CR) o Long delayed conditioning: long delay between the CS and US; light is on for a long time before the food is presented (usually not effective and it can result in inhibition of delay) o Simultaneous conditioning: both are presented at the same time and end at the same time (ineffective or a failure of performance rather than learning) o Backward conditioning: present he US first and then the CS; present the food and then the light (complex results and poorly understood) o Look at chart on page 73 Measurement of Conditioned Responses: o Various measures of CRs • Magnitude of the CR (number of pecks, magnitude of light or sound) • Probability of CR following the CS (look at the chances of an animal doing something, 70% of the time when the light flashes, the person blinks) • Latency of the CR following CS onset (having several seconds or no seconds between the CR and the CS, stronger learning with shorter latency) o CS must be evaluated without contamination by the US (we think we have taught someone to do something, think you blink because of the tone but may be because you blink a lot, have to assess the CS alone) o CSalone test trials: • Delayed and race trace procedures (inherent); we have the CS on its own for a period of time so we can observe the animal at that time and see if before learning happens it does anything) • Simultaneous and backward conditioning (critical); do not have the CS alone to see what it does by itself, have to have some times with CS presented on its own
•
We have to have some sort of control measure
Control Procedures: o Pseudoconditioning (when an US is presented, the animal reacts; if you shock a rat multiple times and then play a loud noise, it jumps, it looks like an association but you have never paired them together) and sensitization effects (the band is so loud that you are sensitized, every time the guitarist jumps around you scream louder) o Ideal control procedure: • Same number and distribution of CS and US events but with CSs and USs arranged so they would not become associated (not close in time or space, even if we think we have found an association, it may be pseudo conditioning) • Random control: can produce associative learning (randomly present shocks, does not depend on the CS, flash of light with a shock, with no shock, shock in the middle of the flash of light), we start to associate even when there are no connections − Explicitly unpaired control (CSs and USs occur in separate sessions), this is regarded as the most successful control procedure Inhibitory Pavlovian Conditioning: o Have stimuli that increase behaviour (ringing of the bell once you have conditioned the association, causes the dog to salivate, can increase it) o Presence of CS signals absence of US: • A stimulus presented tells the animal that something is not going to happen • A kid goes to school and the bully isn’t there tells the kid that he will not be hurt that day • A signal that predicts the absence of an aversive event (like a shock) or an appetitive event (like food) can acquire conditioned inhibitory properties (i.e., can become a conditioned inhibitory stimulus or CS) • Give them a signal that the aversive event will not happen (a substitute teacher comes to class signalling to you that you will not have the test that day) o An inhibitory stimulus elicits a CR is opposite in direction that produced by an excitatory CS (it can suppress the CR elicited by an excitatory CS) o For absence to be significant, the US has to periodically occur in the stiatuion (you still have to have a situation where you flash a light and a shock occurs, if the pain and anxiety goes away, you do not need the light anymore because there is no more shock) o Inhibitory conditioning requires an excitatory context for the particular US being used o Excitatory conditioning doesn’t depend on a special context in the same way o You can teach a rat that the light leads to a shock so every time it sees a light it freezes, you take it out of the box and put it in a room and it sees a light and it will freeze (context doesn’t always matter)
Procedures for Establishing Conditioned Inhibition: o Trial type A: excitatory (CS+ and US); associate flash of light and the shock) o Trial type B: inhibitory (CS+/CS and no US); flash of light and tone and nothing happens o CS presented in excitatory context of CS+ o Have a light and shock, then add C of a tone and then no shock, over the course of time, the animal learns hat the tone and light means no shock Measurement of Conditioned Inhibition: o If an inhibitory CS suppresses the occurrence of the CR how do we measure it? o Bidirectional response systems (heart rate goes up and down) • Possible to directly observe inhibition with some bidirectional response system • If baseline responding is above zero, deflections in both directions from baseline can be detected (ex. sign tracking – approach vs. avoidance) Measurement of Conditioned Inhibition in NonBiDirectional Systems: o Compoundstimulus (summation test) • Present the CS in compound with the CS+ • CS should reduce the size of the CR elicited by the CS+ • Ex. either drinking or not drinking (cannot undrink), measure how much the organism drinks (mL) in a certain amount of time • Stimuli A and B were conditioned as excitatory stimuli by being presented alone with shock (A+ and B+), stimulus X was conditioned as an inhibitor by being presented with stimulus A without shock (AX), stimulus Y was a control stimulus that had not participated in either excitatory or inhibitory conditioning • A was a flashing light, B, X and Y were auditory cues (clicker, white noise etc.) A and AX were tested in the original context o Retardation of acquisition test: • Try and convert the CS to a CS+ • Make a friend that makes you calm and reduce your anxiety (CS) when you are anxious into a friend that increases your anxiety • This should take longer than trying to convert a neutral stimulus into a CS+ Questions: o The interstimulus interval is: the start between the CS and the start of the US o
