Ignoring is a short-term solution with long-term consequences. I recommend:
- Understanding why the interruptions happen
- Removing as many reasons as possible for the interruptions
- Setting boundaries to minimize the interruptions that remain
Understanding the Interruptions
The first step to minimizing interruptions is understanding why your coworker is doing them. People may interrupt for many different reasons:
- They are bored and want a distraction
- They are more extroverted and require socializing
- They don't consider the interruptions to be an imposition
- They want to feel like they are working in a team
- They don't feel comfortable tackling their work alone, etc.
If the interruptions are frequent, you may be able to figure out if one or more of the above (or totally separate reasons) seem to be likely causes for the interruptions. Once you have thought about why it's happening, it's time to try to remove those.
Removing the Causes
So let's say that your coworker just gets bored regularly and needs someone to talk to. It may be that if you take coffee breaks with him at convenient points, he will dramatically reduce the amount of times that he interrupts you.
If he's not feeling comfortable tackling the work on his own (and asking you basic questions you wish he would figure out on his own), you can set up time to go over how to find these things on his own for 20 minutes a day or so.
If he's bored and just wants something to do, you can try to get him to help you with some of your work, or give him some side projects that should be done but you don't have time for and think he can accomplish fairly easily.
By understanding why he's interrupting you, and then finding a way to redirect the interruptions to non-interrupting behavior, you can probably greatly reduce the amount of interruptions.
There will still be interruptions so long as your coworker doesn't understand that the interruptions are disturbing you. So in addition to trying to redirect his energy away from interruptions, you need to find a way to indicate that the interruptions rub you the wrong way.
One way I've seen some offices handle it is to create a "I'm focusing" signal. Something to indicate "do not disturb" like the proverbial necktie on a door handle in a college dorm. Perhaps it could be wearing headphones. Or it could be a wood block with a red and green side that you flip over to indicate your state of focus. Or it could be writing "focus times" on a whiteboard where your coworker can see it and asking him to do the same so you know when to interrupt or not to interrupt.
Be sure to discuss this in a way that doesn't make the person defensive. So rather than just explaining what the signal is and that you shouldn't be interrupted, introduce it as a mutual signal to prevent interruption (meaning he can use it to prevent you from interrupting too).