What is an extinction test?

Question

In Stolerman & Olufsen (2001) I read the sentence:

After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests.

Here is the entire section from the article on the subject of extinction testing:

Extinction test procedure

Effects of test drugs were determined in brief extinction tests of 3 > min duration that took place twice weekly, with normal training sessions continuing on the interven- ing days. Initially, rats were tested once with vehicle and once with the training mixture; they all reached a cri- terion of at least 80% correct responding and they were all used in subsequent experiments. The effects of saline, the single drugs used for training and the training drug mixture were determined in 3-min extinction tests. The different drug treatments were given in random order. Prior to each test, two injections were always given (via the appropriate routes) to equate handling.

What is an extinction test?

Answer 1

It's a behavioral thing. The abstract of the paper says: "...mixtures of two drugs from vehicle in two-lever procedures with food reinforcers..."

In operant behavior, rats (in this case) are trained to associate a stimulus (a tone, an odor, a light, etc.) with an action that leads to a reward, the association is trained by delivering a reward only when the 'correct' action is performed, e.g.:

stim A -> press left lever -> get a reward

stim A -> press right lever -> get nothing (or a punishment, but that is a whole different question)

One can quantify the performance of the animal by looking at the probability of responding left (in this case) when stim A is presented.

Now, we think of the association between stim A and left pressing as being reinforced whenever a reward is present, we call it extinction whenever the reward is not present, basically because the reinforced behavior will eventually extinguish, and we say its extinguished when the probability of response to the left and right is 50%.

"...generali[z]ation to ethanol was examined in extinction tests..." basically means that they substituted stim A for ethanol (I imagine its all olfactory, just read the abstract sorry) and characterize the response to ethanol without ever reinforcing it, hence the extinction.