Halloween is an enigmatic celebration, a time when the normal rules of society are turned upside down. When else can kids dress in kooky costumes, and grownups dole out candy to strangers by the handful?

But it does have some rules, and they can be complicated. As people come out to celebrate, they bring different ideas about everything from decorations to what costumes are appropriate and how much sugar — if any — is OK for kids. And not everyone agrees on what age kids should stop trick-or-treating.

It can leave parents — and anyone taking part — feeling a bit torn.

"There's the side where you want your kids to have this wonderful ritual-like festival," said Colleen Harmeling, an associate professor in the school of business at Florida State University. "But then you're balancing it with these other demands — and those other demands are where morality kind of comes into play."

That means Halloween can be rewarding and fun, and maybe a bit stressful. So we asked Harmeling, who studies how morality affects people's consumption choices, for some insights. And while we'll get to the sticky parts, let's start with the fun.

What do kids get out of Halloween?

"I think it is so much more than a sack of candy," Harmeling said. "I think it is this visibility to the community that they're embedded in. It's a night of fantasy, when they see all of these other kids pretending along with them."

Halloween is like an extended role-playing game that has been thrust into the real world. For millions of kids, it can perform one of the most basic functions of play: easing the pressure and stress they're under.

"It's also a moment where they can in some ways break the rules where it's safe," Harmeling said. "You know, they're wandering in the street. They're among all of these strangers, they're not wearing proper clothes, you know?
So it gives them this freedom to be wild, in a sense.

"That's why it has become such a such a core rite of passage in our culture, because it isn't just candy."

What do adults get out of it?

For grownups, a visit from trick-or-treaters brings real benefits, Harmeling says. It starts at a very basic level.

"They're signaling their appropriate membership in the community," she said. "Like if you are in a high trick-or-treating zone, it's kind of your moral duty to participate, you know, to keep your light on."

"And this is something that I think parents also struggle with," Harmeling said. For instance, parents of young kids might enjoy Halloween — but they could also worry that doorbells and knocking will wake their sleeping toddler. Until recently, Harmeling added, she was in that group herself, trying to balance being a good citizen with being a good parent.

As they take part in what is basically a massive candy redistribution scheme, they also get to dive into their own sense of altruism and feel the warm glow that comes from contributing to their community and helping provide a rite of passage.

Then there's the entertainment factor.

"You're witnessing the enjoyment and the emotional contagion of a collective group" of ecstatic children in costume, Harmeling said, "so there's this shared emotion through all of this."

So, why can Halloween be stressful?

Basically, the communal aspect that makes Halloween unique can also make parents and kids feel scrutinized, and even leave them with a sense that they might not share the same prevailing notions as their neighbors. Even for a seemingly lawless celebration, that's where morals come in.

"Morality is inherently embedded in a community, it is part of what ties the community together," Harmeling said.

Halloween brings chances to build a community, but it also creates conditions where "surveillance" is very high, she added, leading parents to make inferences about what their neighbors are thinking.

One huge debate, of course, is whether sugar is acceptable for children, and how much. And of course, some kids simply can't eat candy due to allergies. Parents might also have different ideas about whether toy swords or guns should be part of costumes. The list of potential internal debates is long.

"Does my neighbor think what I'm doing with my kid is appropriate or inappropriate?" Harmeling said by example. "Are they going to approve of these types of candies? You know, what if we run out of candy, is that a moral failing on our part, or is that just when we shut Halloween down — or what if we don't participate?"

Where do older kids fit in?

If you've ever done a double-take at seemingly adult-sized trick-or-treaters, you're not alone. But there's no hard and fast rule on how old kids should be to take part in Halloween: Even towns that ban older kids from trick or treat don't agree on a cut-off age.

It's a fascinating instance, Harmeling said, where "the same action can be interpreted on both ends of the moral continuum — as a good behavior or bad behavior."

There are often deep reasons behind those interpretations. For example, adults who have strong feelings about it might have been raised in a home with a strict line between childhood and adult experiences.

If you begrudge a teenager a handful of candy, Harmeling said, you can also blame your evolutionary hard-wiring — specifically, our drive to provide for the most vulnerable.

"There's a biological reason behind why you're likely to grab your hand into your bag of candy and throw pounds of it to a three-year-old who's coming to your door, and then offer a single piece to that 13-year-old who's coming to your door," she said. "It's because they are the more innocent, they're the more vulnerable."

Teenagers shouldn't feel vilified if they go out for trick or treat, Harmeling added. And if a child is wavering on whether to go, parents should try to find a way to support them — and make sure Halloween is safe and fun.

"At the end of the day, every parent is trying to raise not a good kid — at all. They're trying to raise a good adult. So if you can help them understand the freedom in recognizing different versions of good, then we will have a better future community."