Possible worlds: imagination gets its due as a real-world thinking tool.

Kids make some unusual friends. Take Simpy, an 8-year-old girl with blue skin and black eyes who likes funny clothes. Then, there's Skateboard Guy. He wears cool shirts and performs amazing tricks on his fancy board, even though he's small enough to chill out in a child's pants pockets. Alicia is only a couple inches high, too, and she has a great sense of humor--for a talking dog with green fur and blue eyes.

These are just a few of the imaginary companions that 7-year-olds have described to psychologists led by Marjorie Taylor of the University of Oregon in Eugene. The team was surprised by how common invented friends are among kids that age.

Nearly one-third of the 100 7-year-olds that the researchers questioned were playing with pretend pals. The psychologists report that, overall, 65 of the children that they tracked from age 3 to 7 reported having hung out with an imaginary buddy at some time in their lives. Many children who had imaginary friends at age 3 later dropped them only to invent a new such friend by age 7.

About one in four of the kids who described a pretend friend had kept it a secret from parents. A diverse cross-section of kids played with make-believe buddies, the team found. Although preschool girls described imaginary companions more often than their male peers did, that sex disparity vanished by age 7.

The youngsters with pretend pals weren't social losers who concocted invisible friends because they couldn't make real ones, nor were they lost in their own dream worlds, testing suggests. All the children keenly appreciated the difference between fantasy and reality.

Imagination infuses most kids' lives in a much broader way, Taylor says. Nearly all the children in the study, regardless of age, regularly pretended to be real and imaginary characters. They sometimes impersonated animals, superheroes, and creatures that they invented themselves.

In the past, kids' imaginative pursuits left most researchers unimpressed. For several decades, psychologists have generally assumed that imagination peaks in the preschool years and then dwindles as children grasp the difference between pretense and reality.

Taylor belongs to a contingent of researchers who regard imagination as a thinking tool. Kids regularly use their imaginations to figure out how the world works and to address mysterious issues, she notes, such as what God looks like and what happened in their families or in the world before they were born. Children also apply fantasy to sidestep pain.

"Fantasy is alive and well in children's lives," Taylor says.

According to Taylor, adults as well as children are imaginative thinkers--even while posing as staunch realists. From plumbers to prime ministers, individuals encounter and converse with others purely in their own thoughts, ponder the future, and rework past events in pleasing ways.

"Imagination is about considering possibilities," Taylor says. "That's fundamental to how people think."

MONSTER IN A BOX A 3-year-old boy enthusiastically describes a scary creature after Harvard University psychologist Paul L. Harris shows the boy a box and asks him to imagine that a monster lives inside it. Nevertheless, the boy reassures Harris that a monster won't pop out if they open the box. The monster is only make-believe, the boy declares with an air of satisfaction.

Harris then leaves the room for a few minutes. Alone with his thoughts, the youngster eyes the box nervously as he moves away from it.

This type of response, which kids regularly display by around age 2, doesn't mean that they fail to distinguish fantasy from reality, in Harris' view. Adults react in comparable ways, he says. In one experiment that he performed, adults filled a bottle with tap water and wrote the word cyanide on a label that they attached to the bottle. The volunteers knew that they were only pretending that the water was poisonous, but most wouldn't drink it.

Taylor points out another example: Grown-ups get "really scared, not pretend scared," while watching horror movies.

In his book The Work of the Imagination (2000, Oxford), Harris proposed that people have evolved a brain system that goes to work appraising emotionally charged situations, whether or not they're real. In fact, responding emotionally to imagined scenarios aids decision making, he holds.

For example, Harris has found a deficit among people who don't show physical signs of emotional involvement, such as an increased heart rate, while reading a suspenseful fictional passage. Such individuals score lower on tests of reasoning and logic than do people who show strong physical and emotional reactions to such tales.

From around the time that children begin to talk, Harris argues, they contemplate not only current and past events in the real world but also imaginary versions of the present and the past, future possibilities, and spiritual or supernatural concerns.

He says that many other developmental psychologists neglect imagination's role in mental development. They assume that children generate reality-based theories primarily to explain what they observe around them, much as scientists do.

However, an architect of the notion of children as theory builders disagrees. Psychologist Alison Gopnik of the University of California, Berkeley regards imagination as fuel for play, with which kids explore the both practical and fantastical implications of what they've surmised. For example, a preschooler may first determine that "Mother gave me this plastic duck because she wants me to play with it." The child then moves into the realm of imagination: "This plastic duck is a magic swan that will fly me up to a cloud castle, where I'll be a princess."

Even 9- to 12-month-olds with bare-bones vocabularies use words imaginatively, Gopnik says. For instance, she has observed babies who say "apple" while pretending to eat a ball of "night-night" while tucking a teddy bear into bed.

Soon thereafter, youngsters parlay actual experiences with parents of other caretakers into what Gopnik calls "theories of love" which provide more grist for imaginative play.

What Gopnik calls theories of love are usually referred to as infants' attachment styles, or what babies have learned about what makes others care for them. For instance, securely attached kids tolerate brief departures by their mothers and greet them warmly when they return, while avoidant youngsters ignore their mothers when they're present and appear unfazed when they leave.

New York City psychoanalyst Anne Erreich suspects that by age 1, infants' attachment styles arise from fantasies, not ideas solely grounded in their experiences as Gopnik proposes. In a 2003 paper, Erreich argued that babies possess innate desires, such as a need for skin-to-skin contact, an impulse to connect emotionally with a caretaker, and a wish to feel safe by staying close to that person. These needs motivate their fantasy life.

Consider the path to fantasy in avoidant children. Erreich points to previous studies that have found that at age 1, these infants display racing hearts and other physical signs of distress when their mothers leave, even though the kids look unconcerned. Home observations indicated that these children accurately perceive that, should they act on their wish to be close to their mothers, they'll be painfully rebuffed.

The child's fantasy that often lurks behind this response, and that frequently emerges consciously later in life, is that some personal flaw in the child caused rejection by the mother, Erreich concludes from her clinical experience with children and adults.

BELIEVE IT OR NOT In 2002, about 1 week before Halloween, 44 Texas preschoolers encountered the Halloween Candy Witch. Researchers visited the kids in their classrooms and told them that the Candy Witch--a character that the investigators had made up--was a nice Witch who visits children's houses on Halloween night and replaces the candy each child has collected with a new toy.

Then, the plot thickened. The night before Halloween, 25 of the youngsters observed their parents pretending to call the Candy Witch. The devious adults told the Candy Witch to come to their house the next night and exchange a toy for Halloween candy after the children were asleep. Late Halloween night, these parents replaced the goodies their kids had brought home with Researcher-supplied toys.

The team, led by Jacqueline D. Woolley of the University of Texas at Austin, was exploring how preschoolers form beliefs about culturally approved fantasy characters such as Santa Claus and the Easter Bunny. An interesting pattern emerged when the Texas children were contacted 1 week after Halloween and again shortly before the next Halloween, Woolley says.

Among the kids whom the Candy Witch had visited, the older ones, between ages 4 and 5, usually said that they expected her to return. Most of those who hadn't had a toy switched for Halloween candy said that they didn't believe in the Candy Witch of that weren't sure whether she was real.

In general, 3- to 4-year-olds reported a weaker belief in the Candy Witch than their older peers did, and the group that had seemingly received house calls from her expressed the most doubt.

Older preschoolers' faith in the fantasy character, ironically, reflected their newfound intellectual sophistication, Woolley and her coworkers proposed in the November 2004 Developmental Science. The 4- to 5-year-olds often discerned a link between the Halloween-night appearance of a new toy and the disappearance of their candy. They then inferred that those events must have been the Candy Witch's doing. Younger kids had a hard time making such connections.

Children have surprisingly subtle conceptions of fantasy creatures, Woolley adds. In other recent work, she and a colleague found that a majority of 3- to 5-year-olds strongly believed in Santa Claus and the Easter Bunny, fantasy figures that adults regularly had told them were real. Few children were uncertain. However, more of the kids told the Researchers that they're not sure or don't know whether fantasy creatures such as dragons and fairies actually exist.

"Young children may have a 'kind of real' category for thinking about fantastic entities," Woolley says.

MIND TRIPS An 8-year-old girl lay screaming on the floor of a consulting room at Stanford University Medical Center. Kicking and fighting with a group of medical personnel, she had good reason to brawl. She was about to undergo a painful procedure that was medically necessary but thoroughly humiliating.

Because of an inborn urinary-tract defect that occurs in as many as 1 in 100 children, physicians had to check annually whether urine was backing up into the girl's kidneys. To do that, they were about to insert a catheter through her urethra into the bladder, inject a dye, and have the girl urinate while being X-rayed.

This year, however, the girl was too big and too determined to give in. Enter Stanford psychiatrist David Spiegel. He came neither to medicate the patient nor to analyze her fears. Spiegel helped the panting, disheveled girl marshal her imagination to induce a relaxed, hypnotic state of mind.

First, Spiegel took the girl aside and asked her to trick the physicians by first imagining that a balloon tied to her wrist was taking her anyplace she wanted to go and by then picturing having fun with her friends there. Although Spiegel typically has kids practice this self-hypnosis technique for a week before using it during the urinary procedure, the girl was a quick study. She returned to the consulting room and patiently endured the arduous checkup.

In the January Pediatrics, Spiegel and his colleagues report similar success with 21 children who have that same medical condition. After learning how to become mentally absorbed in imaginary escapades, these youngsters displayed less distress while undergoing the urinary procedure than did 23 others who received no hypnotic training.

Kids' use of self-hypnosis reduced the procedure's average length from 50 minutes to 35 minutes.

The stress of chronic illness spontaneously jolts children's imaginations, says cultural psychologist Cindy Dell Clark of Pennsylvania State University in Media. Clark interviewed 46 children, ages 5 to 8, who had either diabetes or asthma. Dell's research team also interviewed the parents.

All but one child dealt with medical difficulties by inventing and performing helpful rituals, playing with pretend friends, or behaving in other imaginative ways. One boy with diabetes endured his daily insulin injections by singing out "Hallelujah!"--to the tune of the "Hallelujah Chorus" in Handel's Messiah--as the needle pierced his skin. An asthmatic boy calmed himself while getting his medicine during nighttime asthma attacks by imagining that one of the Teenage Mutant Ninja Turtles pictured on his bedsheets had flown away to fetch the doctor.

IT'S ALIVE Sigmund Freud might have been on to something in 1908 when he wrote that "every child at play behaves like a creative writer, in that he creates a world of his own." In fact, there are striking similarities in behavior between children's imaginary companions and characters in the works of adult fiction writers, according to a study led by Taylor.

Her team interviewed 50 fiction writers, ranging from an award-winning novelist to scribblers who had never been published. Of those authors, 46 provided vivid examples of made-up characters who had taken over the job of composing their life stories and who sometimes resisted their creators' attempts to control the narrative. Some fictional folk wandered around in the writers' houses or otherwise inhabited their everyday world.

Taylor suspects that similar hauntings occur in other jobs in which people predict others' opinions and behaviors.

No matter their occupation, people easily slide into and out of dreamlike states without losing contact with reality, says University of Montreal psychologist Kieron P. O'Connor. 'A woman imagines clearly her father's face in the window, while aware she is physically grounded in a therapist's office," O'Connor and Montreal colleague Frederick Aardema explain in the March Consciousness and Cognition. They give another example: "I imagine myself on a beach in Florida, while driving to work in Montreal."

These imaginary realms, like a fiction writer's creations, sometimes become so absorbing that they render the external world irrelevant, O'Connor argues. For instance, people who seek psychotherapy to quell a constant fear of contamination by dirt typically dwell on the filth that they imagine lurks everywhere, rather than on dirt that can be seen or touched.

O'Connor fights fantasy with fantasy when he treats these people by getting them to imagine the dirt gradually receding into fewer and fewer hiding places.

That makes sense to Harris. "Human beings have a gift for fantasy,' he says.

Real ones do, at any rate. Simpy would rather try on new platform shoes than fantasize about them. Skateboard Guy, like, doesn't care, dude. And Alicia just wags her tail and laughs uproariously.