DISCLAIMER: If you are easily offended/grossed out, do not continue reading.
In the 1920's Ivan Pavlov demonstrated a form of associative learning he called Classical Conditioning, or Pavlovian Conditioning. This experiment describes a type of learning in which there is no relation between the behavior of an animal and a biologically relevant event.
An animal is given a conditioned stimulus (CS), and at first shows no response (conditioned response, CR). However, when an unconditioned stimulus (US) is added an unconditioned response (UR) is seen. After a while, when the CS is given, the US and the UR become irrelevant and the CR is seen.
It is more easily understood in terms of Pavlov's famous experiment where he trained dogs to associate a sound (tone) with food. First the dog was placed into a contraption where they heard a tone (CS), this elicited no response. Next, the dog heard a tone caused by a metronome, and then was given bits of food covered with meat powder (US), causing the dog to salivate (UR). After awhile, whenever the dog heard the metronome, it immediately began to salivate. Eventually the two stimuli become associated and the dog began to produce a behavioral response to the CS. Pavlov called this the conditioned response (CR).
So why is this important? It is important because I have personally experienced this phenomenon on a daily basis for the last 8 months!
Let me explain...
I took a few years off of school so that I could really figure out what I wanted to study, and eventually what career I would pursue. When I started back up again last fall, I realized that after working in a restaurant for years, I was no longer a morning person. {I would wake up at 1:00 pm go to work by 4:00 pm, work until close to 12 or 1:00 am, and not go to bed until close to 4:00 am.} Of course those 8:30 am classes were going to be tough to get used to.
My BF was a great sport and would call me every morning at 6 to wake me up. I personally think the sound of an alarm clock is the worst-sound-in-the-world, so hearing his lovely Dropkick-Murphy's-ringtone made greeting the morning a little easier. At first he would call, and nothing would happen... I'd sleep maybe 5 more minutes, and then wake up and go to the bathroom. After a few weeks, this became routine.
NOW, 8 months later, I have become a product of classical conditioning.
Every time I hear BF's ringtone (CS) I have to go pee (UR)!!!! It doesn't matter what time of day it is, or where I am at, I need to find a bathroom. At first I thought I was nuts and was imagining it. However, I brought it up to BF in December, and he told me that he had noticed every time he called I mentioned I had to pee. He now calls me at inappropriate times, and ungodly hours of the night.
Stupid Pavlov.