Enlarge / Shake, shake, shake: this adorable young child would love to guess what he’s getting for Christmas this year. (credit: Johns Hopkins University)

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2023, each day from December 25 through January 5. Today: New research shows it’s incredibly easy for people watching others shake boxes to tell what they’re up to.

Christmas Day is a time for opening presents and finally ending the suspense of what one is receiving this year, but chances are some of us may have already guessed what’s under the wrapping—perhaps by strategically shaking the boxes for clues about its contents. According to a November paper published in the Proceedings of the National Academy of Sciences, if someone happened to see you shaking a wrapped gift, they would be able to tell from those motions what you were trying to learn by doing so.

“There are few things more delightful than seeing a child’s eyes light up as they pick up a present and wonder what might be inside,” said co-author Chaz Firestone of Johns Hopkins University, who studies how vision and thought interact. “What our work shows is that your mind is able to track the information they are seeking. Just as they might be able to tell what’s inside the box by shaking it around, you can tell what they are trying to figure out when they shake it.” Christmas presents are “the perfect real-life example of our experiment.”