Classical Conditioning Part 2 PDF

Factors that influence the effectiveness of conditioning Contiguity - Temporal (time)/spatial(space) proximity of stimuli - Stimuli that are closer together in time or space are more likely to be associated compared to stimuli that are further apart - Eg. when we see lightning, we ofte...

Factors that influence the effectiveness of conditioning Contiguity - Temporal (time)/spatial(space) proximity of stimuli - Stimuli that are closer together in time or space are more likely to be associated compared to stimuli that are further apart - Eg. when we see lightning, we often expect thunder because they usually occur together in a short span of time temporal - Eg. textbooks often place diagrams next to the corresponding text which is more effective than having them on separate pages - The more contiguous the stimuli are, it means that the closer the conditioned stimulus and unconditioned stimulus are presented during conditioning and it results in easier formation of association - This concept relates back to trace conditioning where the conditioned stimulus and unconditioned stimulus have a time gap between them (the closer they are presented, the easier to form an association) - The long gap reduces the contiguity between the conditioned stimulus and the unconditioned stimulus, making the association harder to establish - A short gap (similar to delayed conditioning) enhances the contiguity and facilitates the association Contingency - Refers to the dependency of one stimulus on another - Forms the strength of the association - If we have perfect contingency then the strength of the association becomes stronger, resulting in a larger or stronger conditioned responding - If we break the contingency up, we will get a reduction in conditioned responding relative to a perfect contingency condition - Good contingency means that the conditioned stimulus reliably predicts the unconditioned stimulus and the conditioned stimulus and unconditioned stimulus always co-occur and never occur separately - Perfect contingency means that the conditioned stimulus to unconditioned stimulus pairing will always occur Contingency (conditioned stimulus pre-exposure) - Exposing the CS to the participants before the trial - In the example above, In the graph above, we see that in the experimental group, the contingency is broken, as CS X (represented by the white bars) is repeatedly presented without the US before conditioning - This weakens the contingency, unlike in the control group, where the CS and the US (represented by the black bars) are always paired. - The phenomenon in the experimental group is called CS pre-exposure. It means that the CS is exposed on its own before conditioning. This results in weaker responding to the CS compared to the control group, which does not receive pre-exposure. This shows how reducing the contingency between the CS and the US lowers the responding, and The CS pre-exposure effect reflects the disruption of the contingency between the CS and the US. - Better contingency leads to stronger conditioning (and stronger responding), while weaker contingency due to CS pre-exposure leads to weaker responding. - The most accepted explanation for this is that the organism reduces its attention to the CS, because it learns to ignore it when it has no consequence. For example, if someone rings a bell repeatedly and nothing happens, you will eventually stop paying attention to the bell. Later, if the bell signals something important, it will take you longer to notice it again, because you have learned to disregard it. Contingency (unconditioned stimulus pre-exposure) - Involves presenting the unconditioned stimulus before conditioning without the conditioned stimulus - By doing this, we disrupt the contingency that exists in the control group where the conditioned stimulus and unconditioned stimulus are always paired - Weaker contingency leads to weaker conditioning  - In the example above, the experimental group shows weaker responding to the CS than the control group, which maintains the contingency between the CS and the US. - A common explanation for this is habituation which refers to the decrease in responding due to repeated stimulation. This happens during conditioning, when the US, such as a mild shock, is repeatedly applied to the rat, for example. The rat eventually becomes accustomed to the shock, even if it is severe. Because of the increased exposure to the shock, the rat shows weaker responding when the shock is paired with the CS. Remember, we are testing the CS, not the US. We never (in most cases) test the US. - Habituation only occurs to the US as it happens with non-associative stimuli (does not happen to CS pre-exposure) - The CS and US do not depend on each other so then we do not pay attention to it Contingency (partial reinforcement) - During the conditioning process - Happens when the conditioned stimulus is present but the unconditioned stimulus is absent on some trials - Important to make sure that there is the same number of unconditioned stimulus presentations in both groups - When a conditioned stimulus is presented but the unconditioned stimulus is absent, it weakens the contingency between the conditioned response and the unconditioned response which lowers the conditioned response - Can be due to partial extinction of the CS on the non-reinforced trials (trials where the CS is presented alone). Every time the CS is presented without the US, it is essentially an extinction trial which reduces the responding to the CS at test. Degraded contingency - Conditioned stimulus is absent but the unconditioned stimulus is present during conditioning  - Important to make sure that there is the same number of unconditioned stimulus presentations in both groups - When the unconditioned stimulus is presented without the conditioned stimulus, it weakens the contingency and lowers the conditioned response - This is likely due to loss of association between the conditioned stimulus and the unconditioned stimulus Contingency (conditioned stimulus post-exposure) - After conditioning - Happens when the conditioned stimulus is present but the unconditioned stimulus is absent - Equivalent to extinction - During extinction, we present the excitatory conditioned stimulus without the unconditioned stimulus and it leads to a decrease in responding Contingency (unconditioned stimulus post-exposure) - When the unconditioned stimulus is presented without the conditioned stimulus after conditioning - This lowers the responding to the conditioned stimulus - Due to the retroactive interference where later learning interferes with the earlier learning - Degree of noticeability of a stimulus - A stimulus that is more noticeable, prominent or attention grabbing is more salient - Intensity of a stimulus - The biological relevance of a stimulus eg. when we are thirsty and we go to a food court, we will just direct our attention on the drinks as that is what we want - Overshadowing: decrease in responding to the target stimulus when it is paired with a more salient stimulus - Interference with the conditioning of a stimulus because of the presence of another more intense stimulus - Eg. when we present a bright spotlight and a dim light together, we will notice the bright spotlight more than the dim light. In this case, the bright spotlight overshadows the dim light. - As a result, the organism will associate the salient stimulus more with the US, and when we test the less salient CS, we will get weaker responding. - Eg. when we mix jalapeno and bell peppers together. The spiciness of the jalapeno will overshadow the flavour of the bell pepper, and we will pay less attention to the bell pepper. Therefore, when we present the bell pepper alone, we will not associate it much with the spiciness, because the jalapeno overshadows the spiciness of the bell pepper - We also consider naturalistic stimuli which are more salient than artificial stimuli Surprisingness: Blocking - The degree of novelty or unpredictability of a trial - Interference with the conditioning of a novel stimulus because of the presence of a previously conditioned stimulus - Blocking: decrease in responding to the target stimulus when it is paired with an already conditioned stimulus - Eg. if a dog is repeatedly exposed to a tone (the first conditioned stimulus, CS1), together with food (the unconditioned stimulus, US), the dog salivates when the tone is presented (conditioned response, CR). - After several consecutive conditioning trials, this time with the tone (CS1) and a light (CS2) together with the food (US), the dog does not salivate (CR) to the light (CS2) when tested separately later. - Stimulus control by the light (CS2) has then been blocked by the earlier pairing of tone (CS1) with the food (US). - Eg. In experimental group phase 1, tone (A) is paired with food and it gave a response of salvation (+). In phase 2, tone (A) is paired with light (X) together with food and it gave a response of salivation (+). So when X (light) is tested, there will be a small conditioned response because it has been blocked by the earlier pairing of the tone (A) and food (+) so the dog will not respond to the light (X) when it is tested alone - Eg. In the control group phase 1, tone (A) is paired with food and it gave a response of salvation (+). However, in phase 2, light (X) was paired only with food which gave a response of salivation (+). Therefore, when X (light) is tested, there will be a conditioned response because there was no stimulus blocking this pairing and the dog is conditioned to X (light) already Novelty: latent inhibition (conditioned stimulus pre-exposure) and unconditioned stimulus pre-exposure - Latent inhibition is the same as conditioned stimulus pre-exposure - When the conditioned stimulus is exposed before conditioning, the responding to the conditioned stimulus is lower than if it was not exposed - Interference with conditioning produced by repeated exposures to the conditioned stimulus before the conditioning trials - Pre-expose the unconditioned stimulus before conditioning - Interference with conditioning produced by repeated exposures to the unconditioned stimulus before the conditioning trials - Both these pre-exposures reduces the responding to the target conditioned stimulus compared to no pre-exposure - This shows that when a stimulus is less novel, the responding to it is lower - Reduces the conditioning effectiveness of that stimulus  - Do not expose the conditioned stimulus and unconditioned stimulus before conditioning as they will no longer be novel when we pair them together therefore lowering the responding to these stimulus - Research has shown that latent inhibition is context specific - Eg. if we pre expose the conditioned stimulus in context one and then condition the stimulus in context two, there will be no reduction in responding to the stimulus - A latent inhibitor only passes the retardation test, not the negative summation test  - The retardation test means that a latent inhibitor is slower to acquire excitatory control than a stimulus that was not pre-exposed - It is likely due to an attention deficit, where the pre-exposed stimulus receives less attention than the non-pre-exposed stimulus. - When we encounter many stimuli in our lives that are irrelevant and meaningless, such as noises and lights. It is adaptive to ignore and filter out those stimuli and focus on the ones that are important. - This also has implications for phobias. There is evidence that if you have had early exposure to dogs in a friendly environment, you are less likely to develop a phobia of dogs if you get bitten by one as an adult, compared to someone who never had dogs. Your early exposure to dogs or other stimuli can protect you from developing a phobia if something aversive happens later. CS-US relevance or belonginess: Garcia and Koelling's Bring and Noisy (and Flavored) Water Experiment - Learning is enhanced when the conditioned stimulus is relevant to the unconditioned stimulus eg. flavored water (CS) and feeling sick (US) - The extent to which the conditioned stimulus is relevant or belongs with the unconditioned stimulus - Organisms tend to better associate certain stimuli with certain outcomes and this could be due to evolutionary dispositions - In this experiment, they divided rats into two groups. They conditioned them with water that had a flavour, and also with some noises and lights, which formed a compound CS. A compound CS means that two or more stimuli are conditioned together. In this case, the flavour and the audio-visual stimuli were the compound CSs. - Later, they shocked half of the rats, and made the other half sick by injecting them with lithium chloride. These made up the two groups of rats. Both groups were conditioned to drink flavoured water with the audio-visual stimuli, which was the compound CS. For half of the rats, the US was a shock, and for the other half, it was sickness. - They observed that the rats that were made sick showed a stronger response to the flavour than to the audio-visual stimuli. They strongly associated the flavour with feeling sick, but not the audio-visual stimuli. The opposite was true for the rats that were shocked. They did not associate the flavour with getting shocked, but they did associate the audio-visual stimuli with getting shocked. This demonstrates that the CS-US relevance, or the compatibility between the CS and the US, determined which part of the stimulus was conditioned or paired with the US. - The experiment by Garcia and Koelling has many implications for phobias and fear conditioning. Some stimuli are universally feared, such as spiders, snakes, and heights. These are the most common phobia targets, because they pose a biological and evolutionary threat to us. Therefore, we are more prone to develop a phobia of them than of stimuli that are not evolutionarily relevant, such as flowers or butterflies. We are unlikely to have a phobia of these stimuli because they were not significant in our evolutionary history. This shows that evolution influences which CSs we associate with which USs. Factors that influence the nature of the conditioned response The US Identity - What we are using as an unconditioned stimulus will influence how the organism responds - Conditioned response is related to the kind of unconditioned response that we are using eg. if we are using a shock as the unconditioned stimuli, the conditioned response is going to be really different than if we are using food as the unconditioned stimuli - Explained by the stimulus substitution model  - The presentation of the UCS activates one area of the brain. Stimulation of the neural area responsible for processing the UCS leads to the activation of a brain center responsible for generating the UCR. In Pavlov's view, an innate, direct connection exists between the UCS brain center and the brain center controlling the UCR; this neural connection allows the UCS to elicit the UCR. - When the conditioned stimulus is presented, it excites a distinct brain area. When the UCS follows the CS, the brain centers responsible for processing the CS and UCS are active at the same time. According to Pavlov (1927), the simultaneous activity in two neural centers leads to a new functional neural pathway between the active centers. The establishment of this neural connection causes the CS to activate the neural center processing the CS, which then arouses the UCS neural center. Activity in the UCS center leads to activation in the response center for the UCR, which then allows the CS to elicit the CR. - In other words, Pavlov is suggesting that the CS becomes a substitute for the UCS and elicits the same response as the UCS; that is, the CR is the UCR, only elicited by the CS instead of the UCS - The theoretical idea that as a result of classical conditioning, participants come to respond to the conditioned stimulus in much the same way that they respond to the unconditioned stimulus - The neurons that get activated by the presence of the unconditioned stimulus can now be activated by the mere presence of the target conditioned stimulus after conditioning - The conditioned stimulus has acquired the same behavioral eliciting properties as that of an unconditioned stimulus - The stimulus substitution model cannot account for the nature of the conditioned response across all experimental paradigms - Conditioned stimulus comes to substitute for the unconditioned stimulus and therefore the conditioned response will look like the unconditioned response - Pre-existing neural connections get established when the conditioned stimulus and the unconditioned stimulus comes together to form an association - If the US identity changes and if affects the CR then it is called the US identity The CS Identity - Conditioned stimulus acquires its own distinct role and meaning which is separate from merely being a substitute for the unconditioned stimulus - In modern learning theory, the CS is not just a replacement for the US, but rather a signal or predictor of the occurrence of the US. This suggests that the CS has its own identity in the learning process. - For example, if a bell (CS) is consistently paired with food (US), the bell becomes a signal that food is coming, even though it doesn't \"substitute\" for food itself - Over time, the CS takes on a distinct representation in the brain, meaning it is recognized as a cue that predicts the US rather than simply being merged with the US's representation. - This allows organisms to respond to the CS based on its identity as a signal for the US, rather than because the CS has somehow become the US. - Research shows that the conditioned response (CR) is often different from the unconditioned response (UR). For example, if a tone (CS) is paired with a shock (US), an animal might show freezing (CR) to the tone, while the UR to the shock might be jumping or flinching. This demonstrates that the CR is not just a weaker version of the UR, supporting the idea that the CS has its own identity - If the CS identity changes and if affects the CR then it is called the CS identity CS-US Interval - Closeness in time/space of the CS and the US - Activating different parts of our behavioural system based on the interval between the conditioned stimulus and the unconditioned stimulus - Eg. We have a tone that presented by food. If the tone is immediately followed by food, then the rat is going to go and immediately start pawing at the food container. - If the tone is followed by food, but there is a two-minute delay at the start, then the rat starts to sniff about different aspects of the cage, it will start to trigger early aspects of that modal action pattern, that foraging behaviour, as opposed to the terminal part. Higher-order conditioning Refers to conditioning without a direct conditioned stimulus and unconditioned stimulus pairing Second order-conditioning - In phase 1, we pair the CS (metronome) with the US (food) and it elicits an UR (salivation) - In phase 2, we pair the second-order stimulus (black square) with the CS (metronome) and it elicits a CR (salivation) - And after all these pairing, when the second-order stimulus (black square) was presented, it elicits a CR (salivation) - It is called second-order conditioning as it was a conditioned response to a stimulus that was never directly paired with the food instead it was paired with a stimulus that itself was paired with food - Refers to the excitatory responding or strong conditioned responding to a stimulus that was never directly paired with the US - Different types of associations that can be formed which cause a CS to produce a response (Associations linked to classical conditioning) - Stimulus-Response (S-R)  - Response that is elicited directly by the CS - Reflexive learning (response occurs without needing US to be present) - Eg. For example, if you take a look at the screen and you read the words on your screen, you can\'t help but read what\'s happening and understand. But you can\'t just look at these words and not have a response of understanding what that means. So it has become reflexive.... - Stimulus-stimulus (S-S) - Also known as stimulus-outcome association (S-O) - By linking up the CS, it makes you think of the US and therefore you elicit a CR - Response that is elicited by the activation of the US representation (response occurs in anticipation of an outcome or US) - We can do US devaluation to differentiate if the behaviour is driven by an S-R or S-S association - US Devaluation - A procedure that reduces the effectiveness or value of an unconditioned stimulus in eliciting unconditioned behavior after second-order conditioning has already occurred - Eg. once we established the first order conditioning, bell predicts food and it makes the dog salivate - During second order conditioning, we can train the dog with light as the CS and salivation as the CR - We can decrease the value of food so this can be done by giving a group of dogs a lot of food before the experiment and starve the other group of dogs before the experiment - Holland and Rescorla (1975) - In phase 1, the tone is paired with the food and this is the same for both groups. The tone is paired with the food and you\'ve got tone-food association here. - Phase 2 is where they do the devaluation. So for the control group, they are put in this little device and they are spun in circles over and over and over again until they get dizzy and sick. So the rats, although, are not able to throw up, but it makes them really want to throw up and it makes them feel really sick. And the second group, that same rotation is now paired with food. And this essentially devalues food because now food is being paired with punishment. - So you see a lot less responding to the tone relative to the control group because the food that it\'s responding to is no longer valuable. Food is no longer valuable because it has been devalued. - Now you can make the food valuable again by simply presenting the food by itself without the rotation. This weakens the contingency between food and rotation, or food and punishment. And that brings the responding back up again in your experimental group. - An example of S-S learning - What is the underlying mechanism of responding to a second-order stimulus? - Chaining of two S-S associations  - Two S-S associations chained together which leads to a conditioned response - When we present the second-order stimulus, it makes the organism think of the first-order conditioned stimulus which makes them think of the US which makes them respond - Eg. when they look at the black square (second-order stimulus), the dog thinks of the metronome (first-order stimulus) and it makes the dog think of food (US) and therefore he responds by salivating - Single S-S association - The organism only thinks about the second-order stimulus and immediately associates it with the US and therefore responds - It does not think of the first-order conditioned stimulus - Assumes that a conditioned response is elicited by the representation (status) or memory of the US - Eg. when the dog looks at the black square (second-order stimulus), it immediately associates it with food (US) and therefore salivates - Single S-R association (usually the case for second-order conditioning)  - Reflexive response to the stimulus - Assumes that the conditioned response is elicited directly by the CS - The organism does not even think about anything, they just respond - Eg. when the dog looks at the black square (second-order stimulus), he will just respond by salivating - Unable to explain all forms of learning because: - The value of the US can be devalued, and when this happens, responding to the CS that was paired with that US reduces - If the S-R conditioning explained all forms of learning, this means that even when the US gets devalued, responding to the CS will remain strong - When the status of the US changes, the responding toward the CS that was paired with the US will be affected - So how do we determine which of these mechanisms are responsible for second-order conditioned responding? - Extinguish the first-order conditioned stimulus - If we extinguish that stimulus and we still see responding then we know that the link between the first-order conditioned stimulus and the US is not relevant - And this means that it cannot be the chaining of two S-S association - Devalue the US - If we devalue the US and we see a change in responding, we know that it cannot be a single S-S association - Extinguish the CS and devalue the US - If there is no change in behavior then that means that the response is driven by a single S-R system - Second-order conditioned stimulus can slowly become a conditioned inhibitor - For the first few trials, there will be responding to the second-order conditioned stimulus - However after many trials, the second-order conditioned stimulus will become a conditioned inhibitor as it is presented without the US present and therefore it will stop responding Sensory preconditioning - Similar to second-order conditioning but phase 1 and phase 2 are switched - In phase 1, the black square (second-order stimulus) is paired with the metronome (conditioned stimulus) and it gives no conditioned response as they are both neutral stimulus - In phase 2, the metronome (conditioned stimulus) is paired with food (unconditioned stimulus) and it salivates (conditioned response) - So when the black square (second-order stimulus) was presented, the dog salivates Underlying mechanisms behind sensory preconditioning - Sensory preconditioning (SPC) works through S-S associations rather than an S-R association, which means that second-order conditioning and sensory preconditioning seemingly similar procedures operate through different learning mechanisms Control by conditional relations - Includes a third event: modulator - Modulator: - Modulates or varies the validity - Determines the validity of an association between two events - Says whether the association is valid or not valid - Modulation is also called occasion setting  - Ability of an event to modulate the association between the CS-US pairing - Do not possess direct excitatory or inhibitory associations with either the CS or the US - They validate or invalidate the CS-US association - Relatively immune to extinction and counterconditioning - Positive occasion setter: - When occasion setter is present and gets reinforced and when the occasion setter is not present, it does not get reinforced - Sets the occasion for reinforcement - Eg. light (occasion setter) tone gets reinforced when it occurs in the presence of light but when there is no light present, tone does not get reinforced - Negative occasion setter: - When occasion setter is present, it does not get reinforced. However in other occasions when the occasion setter is not present, it gets reinforced - Eg. light (occasion setter) tone does not get reinforced when it occurs in the presence of light but when there is no light present, tone gets reinforced - Occasion setters are another version of higher-order conditioning - They are not simply conditioned stimuli - Occasion setter does not have to have a direct inhibitory association to be a negative occasion setter and neither does it need to have a direct excitatory association with the US to be a positive occasion setter - Do not work through direct S-S association - Work through an indirect manner in which they modulate the validity of the actual conditioned stimulus - They can have a direct association with the US and that direct association can be of opposite valence of their modulatory potential (situations in which we have a negative occasion setter but at the same time there is an excitatory CS orthogonality) - The simple conditioning and occasion setting properties of a single stimulus can be independent - Similar to moderator variable where it affects the relationship of the CS and US pairing Stimulus control by contextual cues - Context can acquire both modulatory properties and direct conditioning - Discrete cues - Stimuli that has a clear beginning and end and can be easily characterized eg. tone, light - Contextual cues - Quite diffuse - No clear beginning or end - Can be critical in determining whether or not to produce some kind of response - Can become conditioned excitor - Can become conditioned inhibitor - Eg. visual, auditory or olfactory features of a room or place - Eg. in the lecture theater, it is crowded, there is only one voice, the room is padded etc - Conditioning contextual cues does not refer to one characteristic in particular, but rather the overall composition and arrangement of the features of a physical space. - Contexts can serve as a conditioned excitors and conditioned inhibitors that can pass both summation and retardation test Questions to ask Why if we devalue the US, it cannot be a single S-S association because I thought in S-S association, the second-order conditioned stimulus is link to the US so when the food is devalued, there will be a change in responding so is that not single S-S association? For sensory preconditioning, are the trials done many times for each stage?