Monkeys, like humans, persist at tasks they've already invested in—even when they don't succeed

If you've ever stayed in a relationship too long or stuck with a project that was going nowhere, you're not alone. Humans are generally reluctant to give up on something they've already committed time and effort to. It's called the "sunk costs" phenomenon, where the more resources we sink into an endeavor, the likelier we are to continue—even if we sense it's futile.