One of the most annoying things you can hear when you’re dealing with a breakup is “Just let it go.” You know you need to move on and get over the heartbreak, but you also need to process those feelings.

Some people are better than others at living a life post-breakup, and are more successful at not bringing the rejection and pain they felt from the breakup into their next relationship. But people have a more difficult time releasing the rejection, because it’s revealing something about who they really are as a person, new Stanford research has discovered.

It turns out that if you believe personality is unchangeable, it’s more likely that romantic rejections will cause you to doubt yourself. You will take the breakup personally and start to question who you are; you’ll worry that you were rejected because of some unrealized flaw.

A study called “Changes in Self-Definition Impede Recovery from Rejection” published in the Personality and Social Psychology Bulletin examined the link between rejection and a person’s sense of self.

“The research shows that very basic beliefs about personality can contribute to whether people recover from, or remain mired in, the pain of rejection,” said Carol Dweck, a professor of psychology who co-authored the paper along with psychology doctoral student Lauren Howe, who was the lead author.

Prior research suggests that people generally know how to handle the emotional pain of rejection, but sometimes, rejections can linger even for years and cause problems for future relationships.

“Few things in life are more traumatic than being rejected by someone who knows you well and then decides that she or he no longer cares for you or wants to be with you,” Dweck said.

Howe and Dweck conducted five studies that involved 891 participants who filled out online surveys about both hypothetical rejections and real-life rejections. The subjects reported how their view of themselves changed due to the rejection. For an example, they rated how much they agreed with this statement: “I worry that there’s something wrong with me because I got rejected.”

In another of the studies, participants were asked if they believed people could change, signaling either a growth mindset (thriving on challenge and seeing failure as an opportunity for growth) or a fixed mindset (assuming your character, intelligence and creative ability are static givens and can’t change in any meaningful way).

Dweck and Howe discovered that participants with a fixed or static view let the romantic rejection linger. Those participants saw rejection as more of a revelation of who they really were, which then caused them to be more closed and defensive in future relationships. So much so, that they were still being negatively influenced by rejections that had happened over five years before.

In contrast, participants with a growth mindset, though still hurt by the breakup, were ready to let it go and could see a bright future for themselves.

“Those who see rejections as revealing a core truth about themselves as a person, something about who they really are, may be more likely to struggle with recovery and carry rejection with them into the future,” said Howe.

It can be very difficult to get over the rejection of a breakup, especially if you interpret it as a condemnation of who you are as a person.

This post originally appeared at YourTango.