Most of us have heard about Pavlov's dog but, a quick run down. Pavlov created a situation in which he was able to study and condition a certain response from his dog. He was able to condition a dog to salivate by simply hearing foot steps . He did this through several steps. First he used an unconditioned stimuli (food) this caused an unconditioned response (salivation). 2nd a neutral stimulus (foot steps) was introduced with the Unconditioned stimuli (food) and we got the unconditioned response (salivation). Step three was to repeat step 2 over and over. Finally you get a conditioned stimuli (footsteps) that leads to the conditioned response (salivation).
Pavlov then applied this to human behavior to show that we have conditioned responses to certain stimuli. An example of this is when my father got home from Vietnam he was walking down the street and a car backfired sending him to the ground. People around him did not dive to the ground because they did not have the same conditioned response to a conditioned stimuli. Another part to this example is extinction. If a car backfired around him now he would not dive to the ground, he would flinch but not dive to the ground. If a conditioned stimuli is not reinforced then eventually it goes away.
When we are writing we need to understand the different unconditional responses and unconditional stimuli that are affecting our character as well as the neutral stimuli that may be turning into conditioned stimuli. An example of this would be that a character has just experienced a traumatic event in which he now cowers from events that are similar to the traumatic event. Eventually the character will get used to similar events (extinction) but in some cases they may never get used to it (PTSD).
What are some ideas you have about using this in a story?