Classical Conditioning PDF

Basic concepts of classical conditioning We are interested in learning that has enduring effects on behaviour and learning that is established by mental associations Classical conditioning - Behavior often occurs in a predictable and ordered sequence such that you can anticipate certain out...

Basic concepts of classical conditioning We are interested in learning that has enduring effects on behaviour and learning that is established by mental associations Classical conditioning - Behavior often occurs in a predictable and ordered sequence such that you can anticipate certain outcomes and prepare for them ahead of time - Goal of classical conditioning (predict and prepare): If we can identify the stimulus which elicits the behaviour, you can anticipate what behaviours are going to occur when you see the stimulus and we can anticipate certain outcomes and prepare for them ahead of time - Refers to learning an association between two stimuli or events eg. learning the relationship between lightning and thunder (when you see lightning, you can predict that there is going to be a clap of thunder very soon and we can prepare ourself by bracing and knowing that there's going to be a very loud sound coming up) - Classical conditioning is about learning to prepare and to predict - We can predict a person's behavior by: - Understanding the underlying processes of behavioural elicitation - Observing the circumstances and the anteceding factors - Understanding that behaviour does not occur spontaneously without reason - We can change a person's behaviour by: - Identifying the anteceding factor that results in the behaviour Conditioning - Learning or training Classical conditioning - Specific method of training - Specific type of procedure used to train - To predict and prepare Association - Link between two or more mental representations eg. doctor-nurse, salt-pepper - Things that tend to go together start to become associated together and as a result of this association, once we see 'a', we can predict that 'b' is going to happen - Pairing of items together results in association (basis for classical conditioning) Pavlov's classical conditioning - Interested in looking at how digestive juices can help people - Origin of classical conditioning: In his experiment, he hooked his dogs up and had little canisters to collect their saliva. To make them salivate, he would feed them. However, his research assistant realized that his dogs start to salivate before getting fed ("psychic secretions") they know that they are getting food before they even got food Classical conditioning paradigm - Before conditioning - Unconditioned stimulus - A stimulus that without any training elicits a specific response - Tends to be things that are biologically significant that we have already evolved to respond to eg. food, loud noises, mates, sex - Unconditioned stimulus will elicit an unconditioned response - Eg. we give the dog food (unconditioned stimulus) and he salivates (unconditioned response) - Eg. a loud noise (unconditioned stimulus) will elicit a scare (unconditioned response) - Unconditioned response - Naturally elicited by an unconditioned stimulus (does not need to be taught how to react to the response) - Eg. food salivation - Eg. sex arousal - Eg, shock/loud noises startle response - Neutral stimulus - A stimulus that does not elicit any response (nothing that is specific or reliable) - Eg. a bell, yellow square - Neutral stimulus does not elicit a response - During conditioning - Pair the neutral stimulus with the unconditioned stimulus which will elicit the unconditioned response - Eg. we pair the food (unconditioned stimulus) with the bell (neutral stimulus) together and it will make the dog salivate (unconditioned response) - After conditioning - After pairing the neutral stimulus and the unconditioned stimulus together, we will test the neutral stimulus by itself - If the stimulus by itself can elicit a response, the stimulus has been conditioned and becomes a conditioned stimulus which elicits the conditioned response - Eg. ringing the bell (conditioned stimulus) makes a dog salivate (conditioned response) - Conditioned stimulus - Initially neutral and later paired with the unconditioned stimulus - Anything that is neutral and can take on associated properties - Conditioned response - Response that has been learnt to adapt to the conditioned stimulus - Conditioned responses to that conditioned stimuli as a result of pairing that conditioned stimulus with that unconditioned stimulus Acquisition (Excitatory Conditioning) Acquisition - When you learn that the conditioned stimulus is followed by an outcome so you acquire this association - Excitatory conditioned stimulus: a conditioned stimulus that predicts the occurrence of the unconditioned stimulus - Increasing a behaviour - Acquiring associations which is called excitatory associations - Explains how classical conditioning works - Formation of associations between a previously neutral stimulus and an unconditioned stimulus that triggers a response - Occurs when the conditioned stimulus is presented together with the unconditioned stimulus, generating an association between the two. With time and repetition of this association, the conditioned stimulus alone can elicit the conditioned response, even in the absence of the original unconditioned stimulus. - Excitatory associations - The conditioned stimulus predicts the occurrence of the outcome - If you train the conditioned stimulus to be followed by an unconditioned stimulus, that conditioned stimulus becomes an excitatory conditioned stimulus - That conditioned stimulus becomes a predictor of the occurrence of the outcome - Behaving in anticipation of the unconditioned stimulus when the stimulus is presented Excitatory conditioning procedure - Talks about how to acquire a conditioned excitatory association - Importance of timing and stimulus duration as it determines how effective this procedure is in conditioning excitation to a stimulus - Inter-stimulus interval - How long the stimulus is - Stimulus duration - Time between the stimulus (conditioned stimulus and the unconditioned stimulus) - Inter-trial interval - The time between one trial to the other trial (time between each learning opportunity) - One trial refers to the presentation of both the conditioned and unconditioned stimulus (add to glossary) - Order of stimulus presentations - Which stimulus should come first? CS or US? - Excitatory conditioning paradigms (training programmes) - Order of stimulus presentations - Delay - When the conditioned stimulus and the unconditioned stimulus either overlaps - OR when the offset of the conditioned stimulus coincides with the onset of the unconditioned stimulus (no gap in between) - The conditioned stimulus is presented first followed by the presentation of the unconditioned stimulus - Results in a very rapid and strong conditioning - Fastest and most effective way of conditioning excitation to a conditioned stimulus (association between conditioned stimulus and unconditioned stimulus is clear cause and effect) - Trace conditioning  - Temporal gap between the end of the conditioned stimulus and the initiation of the unconditioned stimulus (inter-stimulus interval) - A time gap is inserted between the presentation of the conditioned stimulus and the unconditioned stimulus - Length of the trace (distance between the conditioned stimulus and the unconditioned stimulus) is negatively related to the effectiveness of conditioning - The longer the trace is, the weaker the conditioning is - Long-delay - Conditioned stimulus duration is very long eg. 120 seconds to 240 seconds then followed by an unconditioned stimulus - Presentation of the conditioned stimulus is lengthened - Results in early inhibition to the conditioned stimulus which follows a later excitation - An example when a conditioned stimulus can be both the conditioned excitor and the conditioned inhibitor - Organisms learn that US will occur after a long interval following the CS - Timing is important to anticipate US accurately - Eg. if I train the organism in 120 seconds interval and then I test it in a 200 seconds interval, the responding will drop as the organism learns to respond at 120 seconds interval - Simultaneous  - Simultaneous presentation of conditioned stimuli and unconditioned stimuli - No direct demonstration of conditioning or learning (hard to differentiate what we are responding to) - Eg. pairing the bell with food salivating - We do not have certainty to claim that salivation occurred in response to the conditioned stimulus versus the unconditioned stimulus - Backward conditioning - Have an unconditioned stimulus that is then followed by the conditioned stimulus - If you present the conditioned stimulus alone, you will tend to not see any conditioned response Measuring conditioned response These are not always convergent. Sometimes we may see a response in magnitude but not in probability vice versa How do we determine which measure to use? We can look at the behavior in multiple ways and depending on what kind of behaviour we are looking at, it will affect how we will measure it - Magnitude - Eg. how much water the rat drinks, how much the person jumped when you startled them - Probability - Eg. how likely is one to blink - Latency - Eg, how much time it takes to respond or stop responding Extinction (inhibitory conditioning) - Results in a decrease in behaviour - Requires an inhibitor and an excitor - Stop reinforcing a previously excitatory conditioned stimulus - Eg. smell of apple pie is always paired with actually eating it excitatory association between odor and food when you start smelling this odor (conditioned stimulus), you start responding (your stomach starts to growl which is your conditioned response) - Eg. you have a new candle that smells like the apple pie, so you smell the apple pie but there is actually no apple pie (extinction) - Conditioned stimulus is no longer followed by the unconditioned stimulus - Inhibitory association - Conditioned stimulus predicts the absence of the outcome - Conditioned stimulus predicting that the unconditioned stimulus will not occur - Harder and slower to learn Inhibitory conditioning procedures - Sometimes knowing when a negative or an aversive event is going to occur can help reduce stress - Can know when good things or bad things happen - Inhibition is a slave process - Can only predict the absence of an outcome if there is already an expectation of an outcome - Inhibition always follows excitation (we cannot have inhibition without prior excitatory conditioning) we cannot extinguish a conditioned stimulus that was never associated with anything in the first place - Eg. Pavlov's experiment - Conditioned stimulus: bell - Unconditioned stimulus: food - Conditioned response: salivate - Excitatory conditioning: when the dog is presented with the bell, the dog will salivate - Introduce a 3^rd^ stimulus: flashlight - We can do alternate trials of first pairing the bell with the food and then the dog will salivate, the next trial pair the torchlight with the bell and the dog will not salivate - After repeated trials, the dog will learn to associate the presence of light with no food. - When the light is presented or when the food is presented, there will be no salivation - The light from the flashlight has become a conditioned inhibitor - This is a way to extinguish the conditioned response (salivation) from the conditioned stimulus (bell) through the presentation of the conditioned inhibitor (flashlight) - Once we take away the conditioned inhibitor (flashlight) then the conditioned excitor (bell) maintains its excitatory value - There will be 2 conditioned stimulus in inhibitory conditioning we get condition responding (salivate) again - Conditioned Excitor - Conditioned stimulus in the context of excitatory conditioning eg. bell - Conditioned Inhibitor - Conditioned stimulus in the context of inhibitory conditioning eg. flashlight - When the conditioned inhibitor is presented, there will be no conditioned response - When we remove the conditioned inhibitor, we get the conditioned response when the conditioned excitor is presented - Conditioned inhibitor protects the conditioned excitor from losing its excitatory association - Conditioned inhibitor protects the conditioned excitor from extinction - Inhibitory Conditioning paradigms - Pavlovian CI  - Conditioned excitor: A - Conditioned inhibitor: X - +: Unconditioned stimulus is presented which then produces an outcome - -: Unconditioned stimulus is not presented and therefore does not produce an outcome - A+: Conditioned excitor - AX-: Conditioned Inhibitor - Unconditioned stimulus is always below the line and conditioned stimulus is always above the line - Most standard form of training conditioned inhibition and it tends to result in the fastest and strongest inhibition - Differential CI A screenshot of a computer Description automatically generated - Excitor: A - Inhibitor: X - +: Unconditioned stimulus is presented which then produces an outcome - -: Unconditioned stimulus is not presented and therefore does not produce an outcome - A+: Conditioned excitor - X-: Conditioned inhibitor - Whenever X is present, there will be no unconditioned stimulus - Predict the absence of the outcome whenever X is presented as they will know that there is no unconditioned stimulus presented - A little bit harder to learn - X is a stronger inhibitor than the one in the Pavlovian CI - Explicitly Unpaired CI  - Do not have the conditioned excitor - We just have the unconditioned stimulus occurring throughout the session on its own - However, whenever the conditioned inhibitor is present, there is no unconditioned stimulus for a period of time - A lot of trials are needed in a very short period of time to learn this - The context becomes conditioned excitor eg. the environment (walls, objects etc) - Inhibition of delay A screenshot of a computer Description automatically generated - Long conditioned stimulus is presented which follows unconditioned stimulus - It is both simultaneously inhibitory and excitatory - Conditioned excitor is initially a conditioned inhibitor - Eg. in the diagram above, conditioned inhibition in which the early parts of the conditioned stimulus which is under the conditioned inhibition are inhibitory, only at the later part of the conditioned stimulus that we get to see excitatory responding - Eg. we will present the conditioned inhibitor for a long period of time and there will be no response from them because it will take awhile for the unconditioned stimulus to come up - Backwards CI  - Unconditioned stimulus (eg. can follow our biological traits, food) is shown first then the conditioned stimulus (eg. bell) - Forms an implicit association - When the conditioned stimulus occurs, there is not going to be an unconditioned stimulus for a short period of time Measuring CI - More complicated that measuring excitation as it is hard to tell if the stimulus is a conditioned inhibition or a neutral stimulus since both do not produce an outcome - We need to increase responding and then see how the addition of the conditioned inhibitor reduces responding - Conditioned inhibitor must pass both the summation and retardation test to be considered a full-fledged conditioned inhibitor - Two conventional tests to measure conditioned inhibition - Negative summation test/Summation test A screenshot of a computer Description automatically generated - Phase 1 (multiple trials must be done) - Train the inhibitor - A+: Training excitor - A+: conditioned excitor because it gives us an outcome eg. when A (tone) is paired with shock (unconditioned stimulus) produces a fear response eg. freeze - AB-: present the same excitor (tone) but instead we pair it with a different stimulus B (light) does not produce an outcome - Pairing conditioned excitor with a neutral stimulus B lead to stimulus B becoming a conditioned inhibitor - AC-: Presenting a different stimulus eg. smell with the same excitor A (tone) does not produce an outcome - Phase 2 (multiple trials must be done) - Train a new stimulus to be a conditioned excitor - X+: transfer excitor/control excitor to test if inhibitor works as an inhibitor - X+: music paired with shock fear response eg. freeze - X+: becomes a conditioned excitor too (same as A+ in phase 1) - Both A+ (tone paired with shock gives you fear response) and X+ (music paired with shock gives you fear response) are conditioned excitors with different stimulus - Summation Test - Test whether our conditioned inhibitor B eg. light is really an inhibitor - Every time B (light) is presented next to A (tone), there will be no shock however we are not sure if it is because of the pairing of A and B that does not give us shock? What if we were to present B (light) with another excitor (X -- music) to test whether it really became a conditioned inhibitor - We need to present it with another conditioned excitor to be able to tell if the conditioned inhibitor is a conditioned inhibitor since it was always paired with the same conditioned excitor - CR: Large conditioned response - Cr: Medium conditioned response - cr: Small conditioned response (true conditioned inhibitor) - First group: the transfer excitor (music) gets paired with the previously trained conditioned inhibitor (light) and there is a small conditioned response which means that the conditioned inhibitor is a true conditioned inhibitor - Second group: the transfer excitor (music) gets paired with shock and gets a large conditioned response as this is a typical excitatory training since we presented the conditioned excitor alone - Third group: in phase 1, we trained the stimulus A (tone) with a different stimulus C (smell) but in the test, we presented it with stimulus B (light) and therefore there will be a huge conditioned response because these participants have not seen stimulus B before so it is natural for them to react to something that they have never seen before - In this test, we can give the different stimulus values so that we can calculate the value of the conditioned response - In grp 1 - A: +10 - B: -7 - X: +10 (conditioned excitor same as A) - When we pair X and B together, we will get a value of 3 (10 + (-3)) - Grp 2 - A: +10 - B: -7 - X: +10 (conditioned excitor same as A) - When we just present the stimulus X by itself, we will get a +10 value - Grp 3 - A: +10 - C: -7 - X: +10 - B: 0 (neutral stimulus) - When we pair stimulus X and B together, we will get a value of +10 as the participants have not seen stimulus B before and therefore the value of B will be 0 (+10 + 0) - Retardation test  - Excite the stimulus to increase or decrease the value to get hopefully a smaller conditioned response because it is harder for a conditioned inhibitor to unlearn its inhibition properties - Grp 1 - A: +10 - B: -7 - X: +10 (conditioned excitor same as A) - cr: +3 - In the retardation test, we will excite stimulus B once so that the value will increase from -7 to +1 - cr will then become +1 which gives us a smaller conditioned response compared to before - Grp 3 - A: +10 - C: -7 - X: +10 - B: 0 (neutral stimulus) - In the retardation test, we will excite stimulus B one time and it will rise to a value of +8 which therefore gives us a larger conditioned response Why do we need two tests? - It is possible to explain the results of the summation test alone as being due to the organism paying too much attention to the conditioned inhibitor at the expense of attention to the conditioned exhibitor - It is possible to explain the results of the retardation test alone as being due to the organism paying too little attention to the conditioned inhibitor Control procedures - Important to have groups which we can compare the experimental manipulation - Helps us to determine whether how much responding to the conditioned stimulus is actually due to the conditioned stimulus and unconditioned stimulus pairing (was the training actually resulting in the acquisition of an association or is it possible that the increase in responding we observed is due to pseudo-conditioning?) - Pseudo-conditioning - Increase in responding simply due to exposure to the unconditioned stimulus - When we have multiple groups, it\'s really important that they differ in one way - Eg. we have the exact same training in all phases, except for one phase in which we see Group A receives A+ training and Group B does not. Otherwise they\'re 100 percent the same. And so, any difference in responding we see is likely due to the training that this group received, and this group did not - Control procedures - Random control procedures A screenshot of a computer Description automatically generated - Compare pairing the conditioned stimulus and the unconditioned stimulus in one group to another group in which the conditioned stimulus and the unconditioned stimulus are just presented randomly throughout the session - Not ideal - There would be times where the conditioned stimulus and the unconditioned stimulus would be accidentally and randomly paired together and therefore it is possible to get strong responding to this group simply because of random accidental pairings - Explicitly unpaired control  - Better control procedure - Experimenter explicitly separates the conditioned stimulus and the unconditioned stimulus so they are never paired together - Any difference we see in responding to the conditioned stimulus in a group that was received paired versus a group that is unpaired, we can assume that it is due to the pairing of the conditioned stimulus and the unconditioned stimulus together - Counterbalancing - Control for the non-associative properties that certain stimuli may have eg. some stimuli may have more attention grabbing stimuli compared to others - Eg. in this example, we are tasked to raise our hand when we see a green circle and do nothing when we see a red circle - However, this example closely relates to the traffic light association where red light means stop and green light means go therefore in this experiment it is possible that the properties of the red circle being associated already with a traffic light or stop light and the green circle being associated with go already is influencing our behaviour and it is not due to any training specifically so we can counterbalance these effects and switch them around - Instead, we can split our participants into two groups and for one group the participants will raise their hands when they see a red light and do nothing when they see a green light vice versa and if there is no difference between the results of both groups, then we know that the responding is due to training and not any kind of unique properties of the stimulus itself Experimental conditioning paradigms - Fear/aversive conditioning - Learning to associate a stimulus with a negative outcome - Uses an unpleasant conditioned stimulus to elicit a fear response - Procedure that pairs a conditioned stimulus with an aversive unconditioned stimulus eg. shock or loud noise to elicit a fear response - Fear conditioning activates the defensive action pattern which involves the startle response - Learning is shown by a decrease in behaviour eg. freezing or avoiding - Requires multiple trials - Eg. Little Albert Experiment done by Watson and Rayner - They exposed a baby named Albert to a white rat, and then made a loud noise with cymbals behind him. This made Albert startle and cry. After repeated pairings, Albert learned to associate the white rat with the noise, and he cried whenever he saw the rat. This is fear conditioning. Moreover, Albert's fear extended to other objects that resembled the white rat. This is generalisation. - US: loud noise with cymbals - UR: Startle and cry - NS: white rat (a stimulus that does not initially elicit a response) - NS (white rat) + US (loud noise with cymbals) startle and cry - CS: white rat - CR: startle and cry - Fear conditioning is important because it shows that classical conditioning can affect emotional responses, not just physiological responses. - Eg. we can condition fear, embarrassment, or happiness - This means that our emotions can be controlled by stimuli, just like salivation - Fear conditioning can be measured - Fear-potential startle - Increase in the startle response when the conditioned stimulus is present - Eg. a rat that has learned that a light predicts a shock will show a stronger startle response to a loud noise when the light is on than when the light is off. This is because the rat is in a fearful and aroused state, which causes sensitization - Suppression - Decrease in behaviour when the conditioned stimulus is present - Eg. a rat that has learned that a light predicts a shock will freeze more when the light is on than when the light is off. This is because the rat is showing a fear response - Eg of how fear conditioning can be measured - US: shock - UR: freeze - NS: tone - NS (tone) + US (shock) freeze - CS: tone - CR: freeze - A rat is bar pressing for food and hears a tone, which is the CS. The tone is followed by a shock, which is the US. The rat startles, which is the UR. After several pairings, the rat learns to associate the tone with the shock. When the tone is played again, the rat freezes and stops bar pressing, which is the CR (the freezing response). This is lever suppression. Lick suppression is similar, but instead of bar pressing for food, the rat licks water from an outlet. When the tone is played, the rat stops licking, which is also a CR. This shows that the rat's behaviour is suppressed by the fear of the shock US. - Lick suppression - A way of measuring fear conditioning - The higher the bars, the more fear the animal shows. This is because it takes longer to lick a fixed amount of liquid when the animal is fearful - Lever suppression - Another way to measure fear conditioning - The lower the bars, the more fear the animal shows. This is because the bars represent the suppression ratio - Appetitive conditioning - A type of classical conditioning that uses a pleasant US to elicit a positive response - Opposite of aversive conditioning - Eg. in appetitive conditioning, we can use food or sex (pleasant US) - Learning is shown by an increase in behaviour eg. running, approaching - Requires multiple trials - For example, a rat that has learned that a tone predicts food will show more activity when the tone is played because it anticipates the food. - US: food - UR: run towards it - NS: tone - NS (tone) + US (food) run towards it - CS: tone - CR: run towards it - Eyeblink conditioning - Uses stimuli that precede either a shock to the eyelid or a puff of air to the eye - The response is the speed and strength of the eyeblink - Rabbits are commonly used for this experiment - The quicker and harder they blink their eyes, the more they have learned the association between the CS and the US - Requires multiple trials - Infants are also used in this experiment - US: puff of air to the eye - UR: infant blinks - NS: tone - NS (tone) + US (puff of air to the eye) infant blinks - CS: tone - CR: infant blinks - Sign tracking/autoshaping - Involves approaching a stimulus (CS) that predicts a positive outcome - Used for appetitive conditioning - Eg. long box procedure with pigeons - US: food - UR: eating - NS: light - NS (light) + US (food) eating - CS: light - CR: eating - When the light is on, the pigeon expects food. This is classical conditioning. However, the pigeon also pecks at the light, which is sign tracking. This means that the pigeon follows the CS that indicates the availability of the US. The pigeon pecks at the light even though it does not affect the delivery of food. This shows that the pigeon has learned the association between the light and the food. - The stimulus for sign tracking should be discrete and local, such as a visual object. It is easier to track than an auditory stimulus such as sound - The organism will follow the stimulus that indicates the availability of the reward. Sign tracking shows that the organism has learned the association between the stimulus and the reward, even though it is not necessary. For example, pigeons will peck at a light that predicts food, even though they will get the food anyway. - Goal tracking - Involves approaching the unconditioned stimulus rather than the conditioned stimulus - Eg. in a long box procedure with pigeons - A pigeon is exposed to a light, which is the CS, and food, which is the US. The light and food are placed at opposite ends of the box. The pigeon can either peck at the light, which is sign tracking, or go to the food, which is goal tracking - Conditioned taste aversion/preference - Involves learning to avoid or prefer a taste that is paired with a negative or positive consequence - Conditioned stimulus for food is the combination of its smell and sight - Conditioned taste preference - Eg. some people may like the smell and appearance of apple pie if they associate it with their grandma. This is a conditioned taste preference - Eg. study on rats in the lab - Pair water with sugar and food coloring - Rats will drink more of the colored water even without the sugar because they have learned to prefer the colored water. This is because the coloured water has been paired with the sweet taste - US: Water - UR: Sweet taste - NS: sugar and food coloring - NS (sugar and food coloring) + US (water) sweet taste - CS: colored water - CR: sweet taste - Conditioned taste aversion - Stimulus is paired with a negative consequence eg. vomiting - For example, some people may have had the experience of drinking too much alcohol or eating bad food, and then throwing up. They may never want to drink or eat that again; even the smell may make them nauseous. - Conditioned taste aversion is very robust and unique: - It can be formed in one trial eg. one night of drinking too much rum and throwing up can make someone dislike rum forever. - It can occur after a long delay eg. someone who eats at a restaurant and feels sick hours later can associate the sickness with the food they ate - It is very durable and resistant to extinction eg. someone who had a bad experience with lasagna may have trouble eating it again, even if they try many times. - It can be acquired from food that is not the actual cause of the illness eg. For example, someone who is already feeling nauseous and eats a slice of chocolate cake may vomit and associate the most recent thing they ate, the cake, with the vomiting. This can make them avoid chocolate cake in the future even though it may not have been the cause of the illness. - It is highly adaptive. Eg. if one consumes poisonous food, they may not survive to learn from their mistake. Therefore, it is beneficial to form a strong and lasting association between the food and the illness, even if the food is not the actual cause. This explains why conditioned taste aversions can occur after a single exposure and persist even after a long delay between eating and feeling sick. - Has many interesting and important applications - Chemotherapy-induced anorexia, which affects people who are undergoing cancer treatment - Chemotherapy is a harsh treatment that often causes nausea and vomiting. As a result, people may associate the foods they eat with the feeling of sickness, and develop a conditioned taste aversion to them. This can lead to anorexia, as they lose their appetite for any food. To prevent this, some researchers have devised novel flavours that are unlike any other food. They add these flavours to the foods people eat before chemotherapy, so they only associate the novel flavours with the sickness, not the normal foods. This way, they can avoid developing a conditioned taste aversion to the foods they normally eat. This is one example of how conditioned taste aversions can be applied in a beneficial way. - Evaluative conditioning - Changing the emotional value of a stimulus by pairing it with another stimulus of a different value - Change attitudes Question to ask: Why would differential CI be harder to learn when I am just presenting a completely new stimulus to it so there should be no response either ways Is X- in differential CI conditioned inhibitor?