We were shown a video of a man who turned away from a bad smell (smelling salts, aka ammonium carbonate) and then under hypnosis, it was suggested that it actuall was a great perfume and he smelled it without a problem.
Afterwards, we were asked if this validated hypnosis, and my argument was that smells that did not affect us physically (vs those that poisoned us, for example) did not necessarily trigger an involuntary flee response. My evidence was that if bad smell alone had that power, how many diapers would go unchanged?
Imho, a smell that is merely bad doesn’t necessarily trigger a physical response through experience and concentration, and people who have to work with bad smells over time get used to it.
The standard accepted answer, I think, is that humans evolved to avoid things that might hurt or kill us. (duh.) Things that our ancestors were likely to encounter in a natural setting that smell bad, such as rotting corpses, excrement, sulphurous compounds, etc., are also bad for you. They tend to be disease vectors (the 1st two) or simply dangerous to your respiratory or other systems (the last example) and so we avoid them.
I am inclined to distinguish substances that are directly irritating to the nasal mucosa, such as ammonia, and “bad” odors.
Turning away from bad (stinky) odors is not particularly involuntary, at least if most dogs I’ve seen are any indication ; they seem to find them interesting. On the other hand noxious substances do produce an involuntary protective reaction.
As to whether the ability to change response to involuntary reflexes proves or disproves hypnosis theory, I can offer no worthwhile opinion.
I guess that would depend on what is considered “bad.” We develop strong emotional responses to smells and I remember reading that sometimes an odor can be very easy to recall when we smell it again. What might not be unpleasant for one person may trigger a traumatic response that is involuntary.
I’m afraid my post is my cite. A few years ago I was having some dental work done. For some purpose the dentist began to use ether without telling me and he had a fighting woman on his hands. The last time I had smelled ether, I was a frightened four year old about to be put to sleep for an operation and that is what I instantly seemed to return to involuntarily when I smelled it again.
Some people also have an involuntary gag reflex when they smell something as bad as a dead body. There are things that you can do to make it easier and you do get used to it, but it always smells really bad.
What smells bad to us doesn’t necessarily smell bad to a dog or a vulture.