It's hard to give a direct answer to this. Psychedelics do open the doors of perception, and allow the senses to process information that is blocked while we are in the everyday state of consciousness. However, even when we are under the influence of psychedelics, what we see comes in images we are ready to accept. So maybe intelligent aliens are just an image of something totally different. Go figure, like Nuggler'd say...
Possible....
I mean, with the use of LSD, the pupils dilate excessively to almost black, which allows for more light and information to pass through the eyes to the brain then normal. During my experiences a few years back I cam to the conclusion that what people describe about LSD, like making you think spiders are all over the place or some pink elephant is trying to kill you has never once occured to me during any of those experiences.
What has occured was that I noticed everything had a level of "Life" to it.... movement where they didn't move. Like you would look at a picture on the wall of a beach with palm trees and although the picture wasn't jumping all over your house, what did occur was that the clouds in the backgroun were gradually moving, the leaves on the trees were blowing, the whisps of water along the shoreline was still in a motion of crashing on the beach..... it all looked like a still frame loop of several seconds surrounding the time of when the image was captured.
If you looked at walls, the walls seemed to have a mild throb or movement to it, as though it was breathing. Everything seemed to be moving at the molecular level.... the Atoms perhaps.
As the narcotic wore off, the pupils gradually reverted back to their normal size and as it did this, those details in everything seemed to fade away back to normal in an equal form..... and then it was back to the everyday life experience.
What I feel a halucenation is is when you actually think there's something completely crazy coming at you like some sponge in the bathtub with a knife trying to leap at your throat..... I never had something like that occur..... but what I saw during these experiences was something more then just a simple halucenation..... there is more to everything that surrounds us then what meets the eye on a normal day...... there is what some call
"A Great Devide" and through most of our lives, we're on one side.... things like Salvia, Shrooms or LSD only bring you to the devide to see the other side, but you can never physically reach the other side until you die..... which I believe is why some people have died in some questionable situations under the influence of some of these things.....
They peered towards the other side for way too long and forgot about the great devide.... and perhaps sought out a way to touch the other side..... so they feel they want to fly off the top of a building or something before they go.... and thus, that's how they died.... which to many seemed like suicide.... and I guess perhaps in a frame of mind, it was.
But in another frame of mind, it could just be that they had enough growing up in this side of existence and wanted to move forward with their overall existence.
That is also why I do not tell/promote people to try these things, and if they're going to try them regardless, I only suggest that they make sure they do it in the company of friends and those who have previous experience trying those things in order to talk you out/down of a difficult and/or dangerous situation you might decide to put yourself through.
Those types of things are not for the weak of mind or those who do not have a lot of self confidence in their abilities to expose themselves to the unknown.