The habenula is a brain structure that regulates dopamine and serotonin production. Its evolutionary purpose is to prevent repeated dangerous failures — telling a rat not to go down the same dead-end path, or telling a defeated lion not to challenge a stronger rival again. It suppresses reward signals when failure is perceived, reducing motivation to retry.
In modern humans, this mechanism becomes pathological. People who are depressed often have a habenula that perceives failure even before it happens, creating the classic depressive experience: “there’s no way out, there’s never going to be a way out, I’m never going to succeed, this is going to last forever.” The biological mechanism designed to keep us safe becomes the prison.
“People who are depressed often have like the habenula is not working in the same way — it’s perceiving failure even before it happens. So then you don’t even try.”
This is why reframing failure as iteration isn’t just a mindset trick — it’s working directly against a neurobiological mechanism that otherwise shuts down effort and hope.