I have wondered why we humans are gifted with imagination qualia in the first place. I have in this post indicated that the human thought process depends on us imagining a conversation with ourselves, so that imagined sound qualia seem indispensable for thought. But since every real qualia can also be imagined, I am not sure whether this is purposeful or just an artifact of the operation of the brain. Also, does this mean that lower animals (from worms to other primates) too are endowed with the power to imagine qualia? I wonder what their evolutionary purpose would be then, the same way one wonders what the evolutionary purpose of dreams is.
One scenario where imagining qualia might be helpful (at least in the case of humans) might have to do with procedural memory. As someone who is learning the guitar currently, it sometimes happens that I have some spare time when I wish I had a guitar with me so that I could practice (which unfortunately I don't always do, as when I am not at home).
On a recent short flight, having run out of books to read, I thought I would practice on an imaginary guitar. I vividly imagined myself playing a guitar, and that included missteps like fretting and picking the wrong strings and so on, and correcting myself during repetitions. And just like a "real" practice session, my fingers (especially my left pinkie) started getting tired after a while (the tiredness was again imagined). All this time, I didn't physically move my hands at all!
Please note that this wasn't me dreaming playing a guitar. Instead, from just a mental standpoint, I was involved in this virtual practice just as much as I would have been when I actually have a guitar to play. The conscious decisions made by me were no different.
Which brings about an interesting question which is, would this kind of imagined practice count towards actual improvement? Of course, there is no substitute for an actual guitar in one's hands, but I would be curious to know if an hour of imagined practice amounts to at least 10 minutes of real practice. And how does an hour of playing the guitar in one's dream count towards real practice?
I am not sure if any controlled experiments have been conducted with regards to imagined practice of some procedural task, and see if that results in any positive effect. It need not be limited to learning a musical instrument, but can extend to any other kind of motor skill like riding a bicycle or even juggling.
While the above have to do with motor skills, there are instances where imagination qualia are almost a requirement in some skill sets. For example, consider professional music composers who are able to notate and arrange music by "hearing" it their heads. Initially they might make mistakes, but with practice, they would narrow the differences between what they "hear" and what they notate correspond to.
Going back to motor skills, it seems like imagining practicing some skill is not a requirement to learn it. But it would be interesting to know if doing so does have any beneficial effect on the procedural memory for that particular skill.