New research suggests that the way we celebrate Halloween is changing.

Halloween seems like it should be a fairly predictable holiday, doesn’t it? While some adults may attend parties, the day is largely for the young. Every year, children go trick-or-treating and bring back hefty hauls of candy, while their older siblings wander the neighborhood causing minor mischief.

But if retailers think they already know how to handle Halloween, they should think again. New research suggests that the way millennials are celebrating the holiday is changing.

“Consumers between the ages of 18 and 34 are the most likely to spend money on Halloween costumes.”

According to a survey by the National Retail Federation, spending on Halloween-related purchases is expected to reach $8.4 billion this year – an 11-year high.

“Retailers are preparing for the day by offering a wide variety of options in costumes, decorations and candy, while being aggressive with their promotions to capture the most out of this shopping event,” NRF President and CEO Matthew Shay said in a statement.

Specifically, consumers between the ages of 18 and 34 are the most likely to spend money on Halloween costumes, according to the study. They are also spending more than other adults and attending parties at higher rates.

The NRF suggested that the spread of social media is at least partially responsible for this trend. With everyone sharing pictures of their creative costume ideas with friends, peer pressure – even if unintentional – can be intense. Partygoers want to be able to show off, and retailers can take advantage of this by marketing unique costumes and decorations for the holiday. Some may even want to consider hosting special events of their own.

Want information on more retail trends? Visit the Visual Retail Plus blog.