Before anyone gets too excited at the thought of a hot toddy by the fireplace on a cold winter night, that's not the kind of cocktail I am writing about. Sorry to disappoint. This article is about odor cocktails.
When training detector dogs, some people train one odor at a time. For example, a narcotics dog would first be trained on marijuana (at least in states where marijuana is still illegal.) Once the dog shows firm odor recognition and response on marijuana, other narcotics odors (cocaine, heroin, methamphetamine, LSD, MDMA, PCP) would be added one at a time to the dog's "library" of target odors. The odors are added by either pairing each additional odor with the prior odor, pairing each odor individually with the reward, or rewarding the dog when it shows interest in the newer/novel odor thus adding it to the dog's "library" of target odors.
Another method is to put all of the desired odors to be trained together into a "cocktail." In the case of UKC Nosework, this means the dog is imprinted on all five odors (birch, anise, clove, myrrh, vetiver) at the same time. The rationale being that a dog processes and catalogs each of the odors individually even when they are presented together.
The best way to describe this capability is with the "stew" analogy. When a human walks into a kitchen with stew on the stove, we usually identify the odor as just "stew" or maybe "beef stew." When a dog walks (or runs as the case may be) into the same kitchen, he logs into his brain each and every individual ingredient in the stew: beef, carrots, pepper, salt, celery, bay leaves, and so on. By imprinting the dog using a "cocktail" the dog is presented with the full library of odors he will be asked to detect.
Because so many people participating in Nosework train obedience and other disciplines using operant conditioning and shaping, their dogs have learned to offer behaviors to gain rewards. These dogs are often times more likely to offer trained indications at novel odors if initially trained one odor at a time rather than imprinting all of the odors together in a cocktail.
Training with a "cocktail" provides the complete odor "library" to the dog right away, leaving no ambiguity re target odor. It is a very efficient way to train multiple odors and is less likely to produce a dog that responds with false indications to novel odors. So, happy sniffing and bottoms up!