The north side of San Francisco is lined with large stately homes, brick and stone exemplars of architectural revivalism. Built in the late 19th century and the first part of the last, these were the houses of the city’s industrialists and bankers. Today they are the homes of the modern titans, the tech CEOs and financiers, who, like their predecessors, enjoy a peaceful remove from the rest of the city. But there is one night a year, the teeming masses swarm at their front doors—for candy.
For all but one of the last eight years, Zillow has named San Francisco as the best city for trick-or-treating and the tony northern neighborhoods of Presidio Heights and Seacliff as the top ranked to visit on Halloween. There’s a reason for this. Zillow’s economists base their rankings on things like walkability scores and number of children under the age of 10. But even the littlest Jedi knights and Hermiones know that the most important indicator in their investment of the night is yield.
There is one can’t miss house that has become legendary for their largesse: they hand out full-size candy, specifically Toblerone bars. When the prominent family moved in some twenty years ago, Halloween was a sleepy and underwhelming evening and the parents decided to up the ante to foster a sense of community and festivity amongst their neighbors. They now stock boxes of the triangular Swiss chocolate, as well as a changing variety of Sour Patch Kids, full-size Snickers and sometimes even small plush toys for the sugar-averse.
Growing up, many of us knew of that “one house” that gave out full size treats. But with more stores than ever pushing full-size treats this year, and many residents who go fun-size feeling pressure to give not just one bar but several to each trick or treater, this year Halloween is raising some interesting economic quandaries.
Fun-size vs. full-size
Stores signal expectations to the consumer by what they display, notes Wharton professor of marketing and psychology Deborah Small. A recent visit to a Skokie, IL-area Costco found boxes upon boxes of full-size Starburst and Skittle varieties and 30-count boxes of Hershey bars, Reese’s peanut butter cups and Kit Kats. Amazon, under its “The Halloween Store” banner, is stocking these variety packs of full-size candy in bulk quantities.
A trip to the store to stock up on Halloween candy sends one signal, so does eyeing what our neighbors are handing out or seeing what your child brings home in their treat bag. What you then hand out to trick-or-treaters can then become less about handing out the mini Twix that you secretly love and more about keeping up with the Joneses. Much of what we do is dictated by social norms and by comparison, no one wants to look cheap, says Deloitte behavioral economist Susan Hogan.
Small agrees that people might feel a small compulsion to show off, or at the very least, not be perceived as less than. However, what you give out is much more than a display of wealth status. Your Halloween treats can signal not just what you have, but aspects of your character, such as your generosity. “A lot of this has to do with social signaling and how they want to look to others and how people want to look is complex—high status and wealthy and caring and moral,” Small said.
You are what you give
Social media amplifies any moment and puts our focus much more on our public self and how we are viewed by the public. “It’s a halo effect too,” Hogan said. “If I give out big candy, am I generous? Am I rich? Am I successful?” She said that Halloween is an opportunity to tell our neighbors who we are.
But it’s also an opportunity to get in line with our peers or differentiate ourselves from them. “There is a tension between wanting to conform,” Small said. “And also be different.”
In the small town of Ross, CA, a wealthy enclave in Marin County, north of San Francisco, the street of Shady Lane is closed off to cars on Halloween and local families from the area and surrounding towns descend for trick-or-treating. Most of the houses embrace the spirit, decorating their houses and garages—some set up music systems and photo booths and bars, so it’s not just the kids who leave their driveway with a treat, but their parents too. It’s the vibe of a spooky block party or tailgate with most houses, but not all, getting involved. One family who moved in several years ago when their kids were small had heard, but not experienced, that Shady Lane was a bit “extra” on Halloween. It wasn’t until each new neighbor’s welcome to the neighborhood was punctuated by, “Get ready for Halloween!” that it really sunk in: they had bought not just a new house, but also a new commitment to a holiday. The first year the family went full-size and bought 1,000 candy bars. But they got a large number of repeat kids and switched the next year to fun-size. This has worked well because in keeping with the over-the-top spirit of Shady Lane, each goblin gets two pieces, but if the bowl starts to run low, they have the flexibility to give out one.
And while 85% of households still prefer to give out the smaller Halloween candy sizes, according to the National Confectioners Association’s most recent seasonal survey, that means 15% give out full-size treats or other items. “Halloween is our Super Bowl,” Christopher Gindlesperger, SVP of Communication at the trade organization, said. “It’s the biggest candy moment of the year.”
It’s also a moment that does foster a sense of community among neighbors and neighborhoods, like the house in San Francisco that gives out Toblerones because the house is now surrounded by blocks of similarly festively-decorated and generous treat givers. “Halloween is a ritual that is fairly uniting,” Hogan said. “Maybe it’s something people cling to, this one nice thing. Let’s go all out for this ritual [that shows] what we do on the front side of our door versus the back door.”
As for what you should give out this Halloween, Hogan says your choice should be dictated less by what your neighbors are doing and more by what expectations you’ve already set. The behavioral economist says customer dissatisfaction spikes more with companies who have generous reward programs that they can’t maintain than with companies with no reward programs at all. Disconfirmation theory shows our satisfaction is very subjective, she says, it’s not absolute, but driven by what we expect. An act of first-time generosity and then subsequent downgrade to market norms can be a disappointment.
Handing out full-size candy? “There’s a cautionary tale in there,” Hogan said. “You better be willing to stick with it.”
More must-read stories from Fortune:
—Trump’s tax bill has cost homeowners a trillion dollars
—Inside JP Morgan, moving on from WeWork is proving to be a messy proposition
—What is Oyo? Behind Softbank’s latest high-growth, high-valuation bet
—Why the next recession may feel very different than 2008
—Trump’s tariffs were supposed to ding China, but the U.S. economy is getting hit 2.5x harder
Don’t miss the daily Term Sheet, Fortune’s newsletter on deals and dealmakers.