Classical conditioning Forging connections between formerly unrelated events
background • It all started with Ivan Pavlov and his study of the digestive system • Research based on work with animals • Wildly successful – 1905 Nobel Prize • Studied the automatic connection between food (meat) in the mouth and the flow of digestive juices • UCS (meat in mouth) > UCR (saliva)
The big idea • Start with an unconditioned reflex – an automatic connection between a stimulus and a response (meat>saliva) • You can develop new automatic responses by transferring responses from an UCS to an originally neutral stimulus by repetitively pairing them together
Let’s say that a different way • An air puff in the eye (UCS) will always make us blink (UCR) • Flashing a red card won’t • But if we repetitively flash the red card, shortly followed by the air puff, eventually, • Just flashing the red card will make us blink !
New terms • The initially unremarkable red card is a neutral stimulus (NS) • The air puff is an UCS • The blink after just the puff is a UCR • The red card, once it causes a blink all by itself, is a conditioned stimulus (CS) • The blink that follows just the red card is a conditioned response (CR)
examples • That particular corner at you high school • The torturer’s black shoes • The song from that certain summer that reminds you of ….. • Pavlov’s assistants carrying the meat tray • The tone before the shock • The whistling of a V1 “shrieked” • Sexual fetishes
definitions • Classical conditioning (CC) – process by which an organism learns a new association between two paired stimuli; one of which was initially neutral the other producing an unconditional reflex • Unconditioned stimuli (UCS) – an event that constantly and automatically elicits an unconditioned response (UCR)
More definitions • Unconditioned response (UCR) – an action that an UCS elicits • Conditioned response (CR) – action that Conditioned Stimulus elicits; it does not have to be identical to the UCR
perspectives • CC works across species, from the lowly maggot to the most sophisticated human being • In habituation the UCS proved to be meaningless and lost its power over behavior • In CC the initially meaningless CS becomes crucial and works a heavy influence on behavior
More perspectives • CC prepares us for significant events by identifying events that commonly predict them • Gives us advance warning of upcoming threats and opportunities • The more unfamiliar the CS or the more powerful the UCS the faster the CR takes
Other aspects • The process that establishes or strengthens a CR is called acquisition • A CR can even be a thought
Unraveling the connection • Extinction – the decrease or extinguishment of the conditioned response • In CC, extinction takes place when we repeatedly present the CS without the UCS following it
The return of the cs>CR connection • Extinction doesn’t erase the CS>CR connection, it inhibits it • Spontaneous recovery – the temporary return of the extinguished response after a delay
All together now • First we build the CS>CR connection through acquisition, • Then we unravel it through extinction, • If we then stop presenting the CS for a while, once we resume its use, • The CR will return, but not for long, unless it is again paired with the UCS
Extending the connection • The CR can occur even without presentation of the exact CS which formed it, if the new CS is similar enough • Stimulus generalization – the extension or broadening of a CR from the original CS to another, similar stimulus • The more similar the entire setting is, the more likely the new connection will form
Narrowing connections • If differing stimuli, although quite similar to the CS, are never, or rarely, followed by the UCS, then the CR will not emerge • Stimulus generalization – differing responses to differing stimuli that have been followed by differing events
What factor is key to cc? • What causes the connection to form? • Pavlov thought that the most important element in acquisition was how closely the UCS followed the CS. • We call it temporal contiguity or “nearness is good” • After all, the longer the break between the CS and the UCS, the weaker the connection.
Is it just timing? • The concept of blocking. • If a CS/CR link has been established, pairing a new CS with the old CS will not work. • This is true even if the timing is perfect for the new CS. • So, nearness in time is not enough.
The power of prediction • It’s reliability that counts, the CS’ ability to accurately and consistently predict the UCS. • The UCS must be more likely to occur after the CS.
The big picture • CC involves visceral reactions involving the sympathetic nervous system – you feel it in your gut. • It prepares us for important challenges and threats. • But it does not tell us what to do. • For how we learn voluntary, planned behaviors we turn to operant conditioning.