From the research that we and other scientists have conducted, there is absolutely no question in my mind that it is possible to increase a person's empathy and compassion. One can learn to express these qualities to a greater extent.
Exactly how to do it and exactly how much we can change, those are still questions that don't have firm answers and likely it's going to be different for different people. But the fact that we can increase empathy and increase compassion by training a person, that I think is very very solidly based in scientific evidence today.
There are a number of things that I think can be done to increase it. There are strategies that we have investigated scientifically that involve for example recognizing the innate basic goodness in another, recognizing that we all are born with the same wish to be happy and to be free of suffering. And then if you can hold a person, visualize them in your mind and generate thoughts and feelings associated with their well-being, wishing them to be free of suffering, wishing them to have the causes and conditions for genuine happiness and well-being. Going through that process is like exercising a muscle and so that when you are next actually with that person in real life, people report that they respond differently and the research bears that out.