One of the most enduring staged magical illusions, "Pepper's Ghost," makes figures seem to suddenly appear in a room.

The illusion was first performed by John Pepper during a performance of Charles Dickens' "The Haunted Man" on Christmas Eve 1862.

In the original trick, a piece of glass onstage conceals a second, identical room set farther back. When the back room is illuminated, the reflection that had concealed it disappears and figures in it suddenly appear as though in the front room.

Mirrors have been used to entertain people with illusion for centuries.

But now, research shows there's a new mirror trick that could help make eating more enjoyable for lone diners.

In a new study published in Physiology & Behavior, researchers had 16 elderly adults eat popcorn in front of a mirror and then in front of a wall.

Participants eating in front of the mirror ate more, thought the popcorn tasted better and enjoyed the experience more than when eating facing the wall.

Researchers then repeated the mirror experiment with 16 young adults and found that they, too, had more positive experiences eating in front of a mirror.

So, yet again, a mirror has produced a delightful surprise.

If you know an older person who often eats alone (which can lead to eating less), try putting a mirror at his or her table.

It may stimulate the social feeling that causes people to eat more and enjoy the experience. The benefits are real, even if it is an illusion.