"All happy families are alike; each unhappy family is unhappy in its own way." This is how Leo Tolstoy's novel "Anna Karenina" begins. A research finding has emerged that brings to mind the first sentence of the novel.
Professor Kuniaki Yanagisawa and his research team from Kobe University in Japan noted in the Proceedings of the National Academy of Sciences (PNAS) on the 21st that "positive people have similar brain activity structures, while negative individuals are diverse."
The researchers analyzed the medial prefrontal cortex of 87 participants using functional magnetic resonance imaging (fMRI). The medial prefrontal cortex is involved in imagination and emotion. When a certain area of the brain is activated, blood flow increases in that region. fMRI displays these areas in brain images as if lights are turned on.
Participants imagined a positive future for about 10 seconds after hearing, "You will embark on a trip around the world." They also thought about negative futures, such as job loss, or neutral futures. They contemplated death as well. While thinking about these scenarios, participants underwent fMRI scans and filled out a questionnaire measuring their overall attitude toward life.
As a result, positive individuals exhibited similar patterns of brain activity. In contrast, negative individuals showed unique and diverse patterns of brain activity. The researchers stated, "Negative individuals imagine various futures in their own ways."
Positive individuals were able to clearly distinguish between good and bad events. They vividly recalled and emphasized good events while keeping a psychological distance from bad ones. Negative individuals did not manage to make these distinctions effectively. The researchers commented, "Negative individuals each have differences in brain activity."
References
PNAS (2025), DOI : https://www.pnas.org/doi/10.1073/pnas.2511101122