Subliminal ring tones

There are probably a lot of noises that a cell phone can emit without really drawing anyone's attention: quiet bumps, rustles, knocks, muted conversation, etc. In fact, the phone could automatically pick these noises up from its environment a la the Deja Vu House idea.

Even though we don't pay attention to these sorts of background sounds, we still hear them, and sometimes react to them indirectly. A particular sequence and timing (bump ... rustle ... thump), if it reliably occurs before some other event, will eventually start reminding us of that event even if we don't consciously remember the correlation. An outdoors[wo]man might know that the weather is about to change, without having consciously registered the changes in wind pattern, temperature, cloud movement, etc., which presaged the change.

So: each cell phone owner would be conditioned to associate a certain sequence of everyday environmental noises with getting an incoming phone call. This could be done by using them before normal ring tones for a while (on a cell or landline phone), then eventually turning down and eliminating the normal tones like training wheels. Or other techniques involving dangerous psychoactive drugs could be developed.

(aside: I don't think ringer fidelity would be a problem, for two reasons. One, these subliminal ring tones will be quieter than the normal kind, so they should be within the volume range attainable by the regular speaker (actually, I think the speaker and the ringer are the same thing on my phone, but my point is, they're quieter, so the phone should be able to produce sounds more complex than a square wave). Two, according to other annotations on the HB (my main source of news), cell phone mfrs are planning to produce cell phones with higher-fidelity ringers anyway, so that the ring sound can be arbitrary recorded music instead of beeps.)

A crowd of people all carrying Subliminal-Ringing Cell Phones might make slightly more noise than usual, but only slightly, because the phone's background sound mimicry would adapt to the sound level of its environment. Nobody would be notice and be distracted by other peoples' phones, because they are not conditioned to the same sequence of common sounds. However, every now and then, after a sequence of unintrusive, unexceptional sounds, you would suddenly think to look at your cell phone, and its incoming-call light would be blinking.