Why do people get songs "stuck" in their heads?
Why do we get songs "stuck" in our heads?
A song or tune that gets stuck in your head is called an "earworm." Research indicates that it is a common phenomenon (in one study of 556 students, 98% reported having had earworms at some point in time), and that musicians, women, and people with compulsive tendencies are more prone to earworms than others. As of right now the cause is unknown.
Some links: New York Times article, Wikipedia entry
A related New York Times article about musical hallucinations sheds some light on earworms:
from Neuron Network Goes Awry, and Brain Becomes an IPod
"The study also showed that musicians and those with compulsive tendencies are the most afflicted."
-from the article linked by hypnagogue
Dr. Jeffrey Schwartz managed with PET scans to locate the circuit of the brain that keeps firing over and over for no reason in people who have obsessive-compulsive disorder. I think something like the same thing is happening when you get a song stuck in your head. A circuit is firing over and over with no appropriate external stimulus to do so.
I really disagree with the second article which suggests this is always happening anyway in all people but is usually overpowered by external imput. Musical hallucinations don't result from deafness. They tend to occur in hard of hearing people because old people are both prone to bad hearing and the mini-strokes that cause the musical seizures. If they resulted from the deafness, they would arise gradually with the deafness, but they don't. They start all at once, quite suddenly.
I also don't think there is any particular link between "earworms" and musical hallucinations. They seem to coincide in some people, but not others. That is: some people hallucinate the same songs over and over but others have a huge repertoire.
I think it's quite plausible that musical hallucinations could issue largely from a lack of aural stimulation. I once experienced a musical hallucination in a sensory deprivation chamber, and others who try out sensory deprivation sometimes/often report hallucinations as well, and not just of the musical kind. Something about being deprived of sensory input tends to cause sensory hallucinations of various sorts. It may be that some sort of seizure is involved as well, but that doesn't preclude sensory deprivation from entering into the causal story.
I don't think there's any particular link either-- but the article does mention a general neural mechanism that might be similar or common between them. The "random brain signal" idea could account for why songs will sometimes jump into one's mind for no apparent reason. Explaining why the song persists requires something more, however-- e.g. perhaps the 'random' brain signals are actually fairly regular while songs are in the head, or (probably more likely) perhaps there is some kind of feedback mechanism in the relevant neural circuit that promotes its own repetitive firing.
I see your reasoning here, and there's nothing wrong with it. However, from the stories about it by Sacks we learn that mini-stroke and resultant seizures were the cause in the two elderly women he treated. They had both been hard of hearing for quite some time before the music started. The sensory-deprivation tank experiences would suggest the music would follow almost right behind the deafness and keep pace with it: an hour or so of deprivation, and the hallucinations start.
The mind does, indeed, try to make up for sensory deprivation with hallucination in many cases, but I don't think that's what's happening with these elderly, hard of hearing people who suddenly start to hear music.
I don't think deprivation in the relevant sensory channel is the only relevant aspect. For instance, in a sensory deprivation chamber one is robbed of most normal sensory input. For the deaf, getting regular visual, tactile etc. input might interfere with the hallucinatory process. Mindset is another factor-- at least in my experience with sensory deprivation, I was purposely trying to take a kind of meditative mindset and keep my mind as clear as possible. Had I been chatting away with myself and worrying about daily concerns, I doubt I would have had my musical hallucination. And there are undoubtedly other factors that must be accounted for as potentially interfering with or enhancing the musical hallucinations. So I don't think a simple linear relationship between degree of deafness and experience of musical hallucination necessarily follows.
The people in these articles experience these things all the time, or, at least, at any time, not just during periods of deprivation. No amount of trying to distract themselves stops the music. The fact you could have stopped it in the tank by engaging in mental chatter demonstrates it is caused by something other than deprivation in the case of these patients.
As far as tank hallucinations go: deprivation does, indeed, sometimes cause the mind to "fill in" the gaps somehow. I don't believe this is because there are always hallucinations in progress that are being interferred with by reality. The hallucinations caused by deprivation arise from the deprivation, rather than being revealed by it.
Concerning tank stuff:
The article I cited explaining phosphenes mathematically in the phosphene thread might be pertinent here. It mentions that in absence of stimuli, the random firing (an interconnected network is prone to this naturally) of relevant neurons that is normally curtailed by inhibitory neurons, predominates as external activity (and therefore the inhibitors who are stimulated by input) falls silent. It (referring not to lateral, but the change in inhibitory firing during sense dep. in general) is probably what subserves the increased hallucinations during a stint in a sensory deprivation tank.
Concerning the song-in-head phenomenon:
The legendary Oliver Sacks wrote about this (in "man who mistook his wife for a hat") in people who recieved too much l-dopa during the initiation of parkinson's treatment before they could find the right dose; some heard music from highschool all day long, as well as exhibiting external behaviors similar to tourettes.
edit: I just wrote this thing too quickly the first time around. Still very jumbled, but I'm not in the mood for cleaning up too much.
You remember what chapter? I don't recall mention of L-Dopa being associated with hearing music.
A priori $.02:
This connection between "earworms", oc tendencies, and seizures is interesting - I'd never heard about it formally before. But, at least in my case, I find it accurate. I've got a fairly close equivalent to a musical "photographic" memory (memory, non talent lol) and can (and do) remember lyrics, notes, riffs, etc for the bulk of my iTunes collection (the songs I've listened to several times before), which approximately amounts to 5 to 7 days worth of songs - out of a possible 9.5. Also, I've got several low-grade cyclic habits and tendencies and am currently prescribed for an anti-seizure medication, which is really effective. Interestingly, though, my music memory hasn't been much affected that I know.
PS - PET scans are cool!
My mistake. I scrambled bits of the "reminiscence" and "incontinent nostalgia" chapters, likely as a result of the former (where internal music is the phenomenon in question, and is explained by temporal lobe disruption) referencing the other at the beginning. In the latter chapter L-dopa causes a woman to remember a great many lewd songs, jokes, and limericks (recollections which disappeared after dose adjustment) - but you're right, I don't think she hears them in at all the same way as the temporal-lobe disrupted cases from the previous chapter.
Thanks for pointing it out. Also found your citation of Sacks in the OBE post which reveals a bit of a mistake in my citation in the thread about "moving your consciousness." I gtg now, but I'll get to amending that as well. (I said her problem came from an allergic reaction, whereas it is probably a viral infection as you said; I also spelled proprioception wrong)
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