Few choices are as exciting to a child as what to become on Halloween. Why all the fuss? Any child will tell you: Your costume reflects not so much who you are as who you want to be -- and that is very heady stuff to most grade schoolers.

While it's possible to over analyze what should be a fun night for the kids, child development experts know that a youngster's selection of a Halloween costume reveals some interesting facts about his or her personality:

* Hero or Heroine. The child who dresses up as Superman or Wonder Woman is using a psychological defense called projective identification. The costume reflects the child's ideal self. He wishes for the prowess of the mythical figure as a defense against his own vulnerability. Taken in small doses this can be a healthy mechanism and act as a springboard to further growth. After all, it's the stuff that dreams are made of: That 6-year-old in burgundy and gold just might grow up to be another John Riggins.

It's important, however, for parents not to let the fantasy get out of hand. Too much "make believe" can be dangerous -- as in the case of the 4 1/2-year-old who spread his Superman cape and tried to fly off the garage roof. That's why it's a good idea to spend some time with children in the quiet of your home after they've returned from trick or treating. The costumes should come off, and the candy sampled, as you gently nudge your little ones back to the real world. (The announcement, "There's school tomorrow," might do it if all else fails.)

Death Figures. The child who is preoccupied with ghosts and gore is operating on another level. His costume choice of Skeletor, Dracula or Darth Vader may represent a counterphobic defense mechanism. He confronts his deepest fear (death, abandonment, retaliation, etc.) by, in essence, playing with it. If he can become that which he fears, it can no longer be a threat to him. It's Halloween's equivalent of whistling in the dark.

Monsters. The child who dresses up like a monster in order to scare other people has made a momentary alliance with the dark side of his unconscious to taste its power. If he can elicit shrieks and fright from others he momentarily externalizes his own fears onto someone else. Of course these fears will come back home to roost tomorrow, but with luck they'll be mastered in time, just as most of us manage to tame the irrational fears of our own childhood. Children tend to avoid monster masks until ages 8 to 10 when they can more comfortably and realistically deal with their own psychological demons.

Should parents say "no" to monster costumes? It depends. Know your child. Talk it over. But do not, by any means, force a monster costume on a reluctant child. And if your stay-at-home toddler is frightened by make-believe monsters at your door tonight, ask visitors to remove their masks before they leave. Children under the age of three don't distinguish fantasy from reality as readily as older youngsters.

Cross-Dressing. In the age of Boy George, it's not surprising that girls may want to dress up as He-Man or that boys may want to transform themselves into Miss Strawberry Shortcake. This is no cause for alarm. Halloween is the holiday of make believe, a harmless way to experiment, fantasize and learn.

Fads. Children who jump for the fads -- like Gremlins or E.T. -- are proving that they're with it. They're dressing up more for their peers than for themselves. And what about political characters, especially in this election year? You'll see some little Reagans, Mondales, Bushs and Ferraros at your door tonight, but you can bet it was Mom's and Dad's idea, not the child's.

Fantasy Figures. The fairy tale standards are still popular: pirates and princesses, cowboys and ballerinas. These costumes are fun and are relatively neutral from a psychological standpoint. Good choices for the little ones.

Whatever costume your child picks, be sure to make a point of asking why. Talk about it. You'll learn something, I guarantee.