Danish researchers who slid 20 volunteers into an MRI scanner and showed them holiday pictures reported finding what they called a "Christmas spirit network" in the brain. Five areas responded more strongly to festive images in people who celebrate Christmas than in people who do not.
Then came the twist. In the same paper, published in The BMJ's 2015 Christmas issue, the authors conceded that the Christmas pictures might simply have contained more red than the comparison images, and that their results should ideally be reproduced before anyone draws firm conclusions.
