Hearing voices in sound (1 temporal + 1 pressure) reminds me of a random article I read a few days ago about finding patterns in images (2 spatial). I mention the dimensionality to just reflect that these are perhaps two instances of the same phenomenon:

http://community.wolfram.com/groups/-/m/t/995095

Also, here's a more casual/fun post I happened to read earlier today, coincidentally:

http://www.dailymail.co.uk/femail/article-3280816/What-photo...

> “I thought I was going crazy. When my air conditioner is on, I wake up and hear light conversations. I would go to the window to see if anyone was outside, or I would turn the air conditioner off [and] it would stop. Sometimes it sounds like a radio.”

I have been sleeping with a fan on for six years, to provide background noise so that any outdoor audial perturbations would not disturb me as much. When I have housemates, or I am visiting family, I will often be disturbed so much sometimes, that I will get up and silent my fan because I am very sure that a conversation or break-in is happening downstairs. Every time, I realize it was my imagination, followed by wondering if I am developing schizophrenia or if I am just a hypochondriac, and then I go back to sleep.

> “I would hear faint voices—whispering, conversing, singing, or chanting! It sounded like a crowded room, full of people at a party in a distant room somewhere in the building. After a while I came to enjoy the sound, as they seemed to be enjoying themselves at the ‘party,’ and it helped lull me to sleep at night.”

> If you hear a symphony in Manhattan traffic, thank your auditory pareidolia for relieving your stress

Sounds like the better part of a great LSD trip. Good to know I am not alone in experiencing pareidolia, I thought I was going crazy, too. I can't help but think the background fan is not perfectly consistent background noise. Jitter in the wires due to external forces would lead to variable rotation speed in the motor, which would lead to ups/downs in amplitude and pitch. Our ears are sensitive enough to capture these distortions, and our brains are powerful enough to amplify or attenuate our perception of these distortions. Even if our ears can't capture these perturbations, I would think that the mere innocent thought or knowledge (or, more ominously, paranoia or suspicion) of these distortions is enough to create such a perception by the brain.

Initial Reaction: If you form a vector of time-convolution of the output of the fan with respect to all of your internalized sounds (fragments, phonemes, words, etc.), over all of their possible phases (accents, volume, pitch, etc.), you could see which sounds the fan is most likely to resemble based on how big the corresponding matrix element is compared to the others. Even if the overlap is .01% with a certain sound, if the next leading overlap is 1,000 times smaller, I bet our brains would pick up on that relative difference. I know it does with visual field (e.g. optical illusions), and there is reason to believe that the brain has a grand unified learning algorithm for all data[0][1] (data is normalized as electromagnetic input anyways)

After reading this, that view is challenged:

http://www.haskins.yale.edu/featured/sws/swssentences/senten...

Researchers at Haskins lab have gotten rid of the Fourier components in regular speech, in which case the inner products mentioned above would be zero, and the synthetic sound should be orthogonal to your internalized sounds. Nevertheless, I listened to some of this SWS, and could understand it with 90% accuracy. So, this is very strange. But does it make sense? If you apply a high frequency shift (e.g. gerbils effect) to some function, you can still understand the speech, even though it's effectively orthogonal to the original function. Reading more into the OP paper:

> “spill-over from parts of my auditory system that recognize the air conditioner, or the shower or the sound of the kettle, into areas of my nervous system that are responsible for processing speech and language.” He went on, “And that spillover doesn’t require similarity. It just requires some kind of shared activity.”

I am starting to like this theory, and reminds me of an earlier conversation on HN about corpus callosotomy not getting rid of spillover from other parts of the brain [2]. But that
"spillover" resulted in useful information transfer, whereas the quote here would suggest it is much more random. Also, it would suggest that the frequency might not be as important as dA_i(t)/dt, for all i, where A_i(t) is the amplitude for the ith frequency, like in Haskins lab.

> But much of our perception of the world also results from the interaction between what we might expect to happen in a given situation, given our beliefs, and the processing of incoming sensory information

This explains why I imagined the sounds as my family or friends talking or someone breaking-in.

> minds impose on random noise, influenced by our idiosyncratic beliefs and predispositions, can also be harmful

Yes, it is important to take action to ensure you are not going crazy. E.g. get up, turn off the fan, and listen: did the conversation/robbery stop? If it did, try it again tomorrow. After several times, one should realize that it is unlikely that the robberies and conversation are happening, and that it is more likely due to brain perception mechanics.

[0] http://newsroom.ucla.edu/releases/ucla-study-shows-brain-s-a...

[1] https://www.google.com/webhp?sourceid=chrome-instant&ion=1&e...

[2] https://news.ycombinator.com/item?id=13503186