You're sitting at your desk, standing in the kitchen, watching TV, etc. All of a sudden, your cell phone vibrates, informing you that you have a new text message, phone call, or email. You reach into your pocket and check, only to find no such message — and, perhaps, that your phone is not even in your pocket in the first place. The vibration felt real, but maybe it wasn't. Regardless, it was not caused by your cell phone.

If this has happened to you, rest assured you are not alone.

In 2010, a team of researchers from Baystate Medical Center in Springfield, Massachusetts asked 232 of their colleagues to answer a questionnaire about phantom vibrations from their cell phone (or, more correctly, from the area where their cell phones usually are). Of the 176 who responded, 115 — 69% — stated that yes, they experienced the disconcerting fake alerts like the type described above. The researcher's plain-as-day conclusion: "Phantom vibration syndrome is common among those who use electronic devices."

What causes it? There are a lot of theories. Discovery News suggested that "[i]t could be because cell phones produce electrical signals that transmit the feeling of vibration directly to a person's nerves or simply because of the mental anticipation of alerts." Mental Floss explains how the first of the two theories would work, likening it to "a physical stimulation similar to what happens when your phone is near a speaker and you hear that weird buzzing sound as it does a 'hand shake' with a cell tower and gives off some electromagnetic interference." And the anticipation aspect is not dissimilar from any other sort of psychological conditioning — we are so used to our phones vibrating that our brains make it feel like it is happening when we "want," not when it actually does.

There's some newer evidence suggesting that it's all in our heads. In July of 2012, researchers published a study on the phantom vibration phenomenon after speaking with undergraduate students about the fake shakes. The vast majority experienced the vibrations, but, as Slate explains, the study found that extroverts and neurotics had it happen more often than the others:

Extroverts, the theory goes, check their phones a lot because keeping in touch with friends is a big part of their lives. Neurotics, meanwhile, worry a lot about the status of their relationships—so while they may not get as many text messages, they care a lot about what they say.

In any event, most researchers think that the fake vibrations are harmless (albeit annoying) — although there has been very little research into that, too.

Bonus fact: The 1969 Apollo 11 moon landing is a favorite of conspiracy theorists who assert that the landing was faked, and rather filmed on a sound stage. In September 2002, one such conspiracy theorist physically accosted the second man on the moon, Buzz Aldrin (whose mother's maiden name was Moon!), demanding he swear upon a Bible (that the conspiracy theorist brought with him) that the landing was faked. Instead, Aldrin punched the guy. Authorities declined to press charges against Aldrin. (Here's a video of the punch.)

From the Archives: Teen Away: A high-pitched noise that most teenagers can hear, but most older people can't. (And how teens are using that sound to hide their text messaging habits.)

Related: Did your cell phone's vibrating motor peter out? You can buy just that piece.

Photo: Man Repeller