4 - Classical conditioning Flashcards
Name the basic conditioning phenomena.
acquisition; extinction; stimulus generalization and
discrimination; context fear generalization and discrimination;
phobias
What is acquisition?
- The process of developing (acquiring) and strengthening a conditioned response through repeated pairings of NS with US
- It proceeds rapidly during early conditioning trials, then gradually levels off
What are the factors influencing the speed of acquisition?
1) Intensity of the US
→ More intense US produce stronger and more rapid conditioning than less intense US
→ Example: when the US consists of a large amount of food or a highly preferred food, conditioning is stronger (more salivation)
2) Intensity of the NS
→ Similarly, a stronger NS will produce stronger conditioning
→ Example: when the NS consists of a louder metronome (paired with food), conditioning is stronger (amount of salivation)
What is the asymptote of conditioning?
The maximum level of conditioning possible
True or false: Aversive conditioning tends to be acquired rapidly.
True: Often only requires a single trial
→ i.e. Context Fear Conditioning: if given a shock (US) while in a certain box (NS), the animal will quickly learn to fear that box (CS)
What is extinction?
- Extinction is the weakening or elimination of a CR when the CS is repeatedly presented in the absence of the US
→ p.ex: if we keep presenting the metronome without the food - Extinction is not simply a process of unlearning the conditioning
→ Extinction involves learning something new about the CS - New conditioning inhibits the occurrence of the CR in the presence of the CS
- The term extinction also applies to the procedure whereby repeated presentation of the conditioned stimulus in the absence of the unconditioned stimulus can also happen
Give an example of extinction
- In the metronome (NS) example, let’s say it has been paired with food (US), such that it now elicits an UR of salivation
→ once this pairing has happened, the metronome is no longer a NS, it is now a CS, and now the salivation is a CR
→ if we now continue to present the metronome by itself, the CR of salivation will eventually die out
→ once the metronome is completely extinguished, it becomes a NS again
What happens to the CR after extinction?
- The CR decreases in strength
- It has not been completely eliminated
→ you can get to a point where the dog doesn’t salivate when he sees the metronome, BUT, the memory of the pairing is still present (trace memory) - The CR can be reacquired quite rapidly when the CS (or ‘NS’) is again paired with the US
→ the ‘NS’ is no longer a pure neutral stimulus
→ Example: pair the metronome with food following an extinction procedure will take less time than it did initially - The extinction does not completely eliminate the effect of conditioning
→ because of the trace memory, it can come back even following the extinction
What is spontaneous recovery and when does it occur?
- The reappearance of a CR following a rest period after extinction
- An extinguished response can reappear even in the absence of further pairings between the CS and US
- This recovery doesn’t last forever; Each time the response recovers it is somewhat weaker and is extinguished more quickly than before
- Especially pertinent when trying to extinguish a fear conditioned response
→ several sessions will be needed to entirely extinguish it
→ p.ex: being anxious at the beginning of a date, then getting comfortable but at the next date still feeling anxious at the beginning; it’ll take some time to feel entirely comfortable from the get-go
What is disinhibition?
- Support for the notion that extinction involves a buildup of inhibition is also provided by a phenomenon known as disinhibition
- Disinhibition is the sudden recovery of a response during an extinction procedure when a novel stimulus is introduced
→ p.ex: when you get more comfortable with class presentations, the anxiety might come back when someone comes in late in class because of the shift in environment
–> p.ex: following repeated presentations of the metronome once it was conditioned, the salivation weakens, but once we introduce a novel humming noise, the salivation returns in strength
What is stimulus generalization?
- The tendency for a CR to occur in the presence of a stimulus that is similar to the CS
- The more similar the stimulus is to the original CS, the stronger the response
- It is an important evolutionary adaptation
→ Example: If we learn to fear a poisonous spider, it is far more adaptive to learn to fear other spiders as well, particularly those spiders that look similar to the one that bit us - Generalization can increase over time
→ p.ex: after being bitten by a dog, a child will fear other types of dogs as well, and the child is particularly likely to more fear dogs similar to the original one
What is stimulus discrimination?
- The opposite of generalization
- The tendency for a response to be elicited more by one stimulus than another
- This can be deliberately trained through discrimination training
→ being able to find differences in the spectrum of the same stimulus
Will rats generalize or discriminate in recent fear memories and in older fear memories?
- For recent fear memories (1 day), rats will discriminate between contexts
→ They will freeze in Context-A (previously paired with shock), but not in Context-B (never paired with shock) - For older fear memories (1 month), rats will generalize (not discriminate) between contexts
→ because rats’ long-term memory storage isn’t as expansive as that of humans
→ They will freeze in Context-A (previously paired with shock), and in Context-B (never paired with shock)
How does conditioning explain the development of phobias?
- Not only the classical conditioning of a fear response, but also the overgeneralization of a fear response to inappropriate stimuli
- Overgeneralization of a fear response to a CS can lead to the developments of a phobic response
What are the 3 phases of classical conditioning?
Phase 1: Before conditioning has occurred
- US (meat) -> UR (salivation)
- NS (tone) -> Orientating response
Phase 2: The process of conditioning
- NS (tone) followed by US (meat) -> UR (salivation)
Phase 3: After conditioning has occurred
- CS (tone) -> CR (salivation)
