Hey, all, I've been thinking a lot about cognitive science and what psychedelics have taught me about my own perception of reality, and I've wandered down some pretty interesting paths, specifically this one. I feel like it could go in several different subforums (Science, Through The Looking Glass, Philosophy et), so I'll just leave it here and hope people find it interesting.
I've been thinking about this idea of 'salience,' defined here as:
"The quality of being relevant to the individual processing the information."
This isn't a very helpful definition so here are two examples:
1) If you've ever been in a room with something you're afraid of, you'll remember how the object of your anxiety becomes extremely "important:" forcing you to focus on it and taking up more mental space then other things. This is a negative salience: fear.
2) Another example is if you've ever had class with someone you were physically attracted to, even if you're trying not stare, you find them "interesting" or "tempting" to watch, and even if you're actively trying not to stare, you're investing mental effort into your relationship to them.
If you force yourself to think just about the character of both experiences (ignore the fear and arousal specifically), you'll notice that they're very similar: both stimuli become very hard NOT to think about, look at, or otherwise consider, and thoughts and desires relating to them can be intrusive and hard to control because they are so "relevant." Some might even say they are both "more real," or at least, "more relevant."
Both the scary object and the attractive person would have high levels of salience: they are highly relevant to you on cognitive level and consequently take up a lot of mental space.
For most people (the neurotypical among us), everything in the world has consistent and varying levels of salience, and these different levels of relevancy are how we integrate our perception of reality: by deciding what is important and deserving of our limited mental resources and what is familiar, unimportant, or boring, we make a world that is understandable and navigable.
When people talk about things seeming "more real," (think back to your last psychedelic trip), it may be that things that are salient take up more mental space or are processed with more intensity, causing them to be more highly detailed or "real." Some people refer to this as the HD Vision associated with tripping or being excessively high on cannabis. People having religious experience, psychotic breaks, or tripping on psychedelic drugs all speak of their environments somehow becoming "more real."
Looking for a neurological basis for salience is interesting: dopamine has been implicated in the super-salience of schizophrenics (I'll get to that in a moment), which makes sense. Dopamine, in addition to being the basis for reward and learning may be involved in the processing of information related to salience (making reward-generating stimulus take up mental space): it's certainly not hard to see how the object of sexual desire (which is modulated, in part by dopamine) is made extra-salient through the action of this neurotransmitter.
Serotonin acts as a neuromodulator, and can be tampered with to reduce or produce many mental disorders, both through it's own direct actions on the brain, and it's ability to modulate the release of dopamine.
I posit that more then a few mental disorders are caused by aberrations in our brains perception of salience. There is already evidence that schizophrenics live in a hyper-salient world, where everything is extremely important, and this makes it difficult for them to integrate a coherent picture of reality because everything is so highly salient. Finding deep meaning in seemingly random things might account for the delusions associated with schizotypal disorders, as well as the feelings of "overwhelmed," and "adrift," that schizophrenics complain of.
Depression may be another disorder of salience, however in the opposite direction: things seem irrelevant or unimportant because the entire world is just less salient. People with depression often report feelings that things "don't matter" or "aren't important." In a world where nothing was salient, it would be hard to get worked up about anything.
Anxiety too could be a disorder of salience, only where one particular stimulus becomes salient to the point that it overwhelms the rest of the brains ability to process the relative salience of other parts of the perceived world. OCD as well can be described as a disorder of salience, where trivial things take on tremendous salience (eg: taking an odd number of steps becomes hugely important).
It's very hard to describe the qualia associated with salience beyond vagueness like "how real" or "how important" something feels, and it may be this ineffable quality to salience that makes communicating the subjective experience of altered or aberrant states of consciousness so difficult.
I have mixed feelings about all of this. On one level, I find it extremely interesting, but on another level, I feel like some of the magic has been taken out of psychedlics, by reducing their effects to a specific cognitive effect (altered perception of salience).
Thoughts?
~ND
"There are many paths up the same mountain."