I think part of this is the spring. Although it is cold again tonight, the premature spring has truly arrived. I know this, because my allergies have begun to kick in. I have been sneezing for a couple of days, now, and I have that feeling which is like a swelling in the front of my head. I think that some of the pollens or molds in the air are psychoactive. Maybe they aren't psychoactive for everyone, but they are for me. Every year, spring brings me a heightening of the senses, and it is at this time of year that I am most likely to have those strange experiences of scents and sounds and tastes which come from nowhere and have no apparent source. The scent of popcorn that wasn't there which I experienced the other night was one of these.
I have sometimes wondered if those mass sightings of UFOs we hear of are not the result of some kind of hallucinogenic pollen or mold spores floating on the breeze. I've never seen UFOs myself, but I have heard bird songs from locations where no bird sits, and I have suddenly imagined flavors I have never tasted from any food, but which are, very briefly, as intense and convincing as an orange or an apple. Also, I have occasionally felt a touch when I was not being touched. A person with less skepticism might interpret these as mystical experiences. A person more pessimistic might fear some disease-presaging malfunction of the brain. I suspect spring, when it happens most often. And I suspect that the reason I don't see UFOs is because the part of my brain which controls my visual sense is less susceptible to the effects of the airborne substances which cause these distortions of perception.
Of course, I have no proof of any of this. But I know for sure that when the allergies begin to effect me, I can expect these unexplained phenomena to appear as well. I have come to think of them as compensation for the sneezing and coughing and headaches that are, for me, the price of spring. It is still my favorite season.