Even the best relationships have their bumps. No partner is perfect. No matter how blissful things may have seemed when your relationship first started, there are always a few things that you wish your partner did differently.In many cases, of course, you just choose to accept your partner’s foibles as a part of who they are.But, what if your partner really did work to change? Would that make you happy?QUIZ: How Do You Act in Close Relationships?According to new research published in a 2012 paper in Personality and Social Psychology Bulletin, it depends on what you believe about people’s potential to change their behavior.Based on research by Carol Dweck and her colleagues, these researchers point out that there are two possible mindsets that people can have about behavior in general. You can believe that behavior is fixed (what psychologists call an entity mindset) or that behavior is changeable (what psychologists call an incremental mindset).Consider your own relationship: When you think about your partner’s behaviors that don’t thrill you, do you think these are aspects of behavior that can be changed? Suppose your partner routinely forgets birthdays and other dates of importance to you. Is that because they are fundamentally forgetful or a bit self-centered? Or is it possible that if they worked on this behavior they could change it?RESEARCH: Conscientious Lovers Are More CaringIf you believe that behavior can be changed, then you respond well to efforts by your partner to change. Those efforts increase your happiness with the relationship and your security in the relationship. When you believe that behaviors are fixed, though, then seeing your partner put in effort to change has little influence on your satisfaction and security.So, you might think you ought to adopt the attitude that behaviors can be changed. However, if you think that behaviors can change, and you see that your partner puts in little effort to change their behavior, then you find it frustrating. In that case, your happiness and security go down.Perhaps the healthiest thing you can do is to walk a middle road here. If your partner is basically a good person with the kinds of human limitations we all have, then do your best to accept those limits as part of what makes them unique. At the same time, if your partner makes a concerted effort to change, greet that effort with love and support.Don’t demand change, but appreciate it when it happens.COLUMN: “It’s not You, It’s Him”