There are a few different techniques a person can use to change their thinking patterns, or their views about a particular subject, if he or she choses to work at it consistently.

Before an outline of the techniques, it helps to determine what exactly the reason for any "disinterest" is.  Is it simply apathy or lack of interest in the subject?  Is it a lack of understanding?  Or a lack of empathy?  Are you too busy to take an interest in this just now?  Are there other things that prevent you from taking an interest at this time (illness, worry about a loved one, other stressors)?  So, first, take a bit to determine your answer to these questions.  It will help you decide how to approach the situation.

Now, here are some things that can be done:

First, one way to become interested in a topic is to learn about it.  A bit of research, even just a rudimentary understanding of the topic, can make it more interesting to learn even more.  So, if the subject is typically something you would ignore, try a bit of self-discovery and see if that doesn't help. 

Second, determine exactly why you want or need to be interested; this can be a BIG motivator.  Is it something you simply HAVE to do for work, or to succeed (example, I don't know the first thing about golf, but if I needed to know it in order to conduct business, I think I'd at least understand the scoring, rules and terminology, even if I didn't take lessons.  That way, I could at least converse with others about their game).  But if it's something that your friend/family/partner are involved in, then your goals are different, and so is your motivation.

You may try to challenge yourself or even set a self reward for achievement.  Give yourself a limited time frame to find out more information, or build in a reward (I'll go out for pizza with xxxx once I figure this out).  Incentives can be very powerful.

Also, how you think about the topic and the situation has a HUGE influence on your attitide, and therefore, your actions and interest level.  If you tell yourself every day that you can't stand Y, before long you will indeed hate Y and everything related to it.  But if, every day, you tell yourself Y is a good thing/person, then you will find yourself more interested and nicer to that person.  Your self-talk can create a sea of change in terms of your attitude toward something.  Try telling yourself, at LEAST 3 times a day, that this topic/situation is interesting and worth your time and energy to learn more and understand it.

Sometimes, however ,our lack of interest is due to other issues.  Again, it might be a lack of empathy toward another person that simply makes it very difficult to "care" about their issues.  Or, more personally, you may simply have too many things on your mind, too many of your own stressors, to be interested in something else that is way on the periphery of your priority list (a phrase I use is, I have all my priorities written out on a legal pad and your's didn't even make the list!).  If this is the situation, then you have to take a totally different stand, and realize this is not going to happen right now.  Give yourself a break, and, if possible, tell whoever else is involved that you simply cannot work on this right now---whether it's going with them to learn/watch/hear something, whether it's simply listening to more talk about it that you really cannot concentrate on now, sometimes we have to give ourself permission to be "selfish" and not take on something new.

 Yes it is possible to convince ourselves of just about anything.  Study, self-talk, priority setting, and making time for something in particular, will all help us change our opinion about a certain item. Think back to sometime when you changed how you believed about something.  If you can change what you actually believe is right versus wrong, or what is important or not important, then you can surely convince yourself to be interested in something that seems trivial, if you want. 

Sometimes we do simply HAVE to work on something, there aren't any choices.  In that situation, that becomes the motivation and we simply have to buckle down and get through it.

Well, I hope some of this helps and the next time you are in a situation like this, try telling yourself you ARE interested 3 times a day for 2 to 3 weeks. You will be surprised at the difference you feel toward that topic!  Good Luck!