I've heard some stores use subliminals to stop shoplifting. Is that true?

Yes. Subliminals are being used in various business settings. One New Orleans supermarket buried honesty and productivity messages under background music and reversed cashier shortages and stealing, while two others reduced employee turnover.

The McDonald Medical Center used relaxation messages subliminally in the clinic which reduced patient anxiety 60% and eliminated patient fainting during treatment. Two surprising side effects were the development of more harmonious working relationships and the reduction of smoking among the medical staff members.

I've heard about subliminal tapes that use speeded up voices. Do they work?

Some tapes use accelerated speech, claiming constant repetition at high rates of speed locks in messages. There is no research proving this, however. Normal speech is about 150 words a minute, and studies show that understanding declines rapidly above 300 words a minute. Accelerated speech tapes present subliminal (or sub-audible) messages at 2,300 words a minute or more which appears to be ineffective. None of the Change Your Mind tapes use accelerated speech.