A small study in Belgium found that your brain’s response to certain cognitive tasks changes in different seasons. In the study, the participants were sequestered in a lab—without seasonal cues—for 4½ days four separate times throughout the year. In each session, the participants were deprived of sleep and then allowed to recover, at which point researchers measured the participants’ brain function as they performed two different tasks: one requiring sustained attention, and one requiring them to use their working memory (aka how we keep track of short-term information we’ve learned until we need to use it).
While their test scores were stable throughout the seasons, the researchers found that the “cost” of cognition (or the neural resources the participants had available) changed depending on the time of year. Turns out, we have less brain activity around cognitive tasks like attention in the winter versus in the summer, and more brain activity around memory in the autumn than in the spring.