Why don’t people help others more? – part 2

In part 1, I talked about some ways in which we might motivate people to be more altruistic. Providing a personal connection with the victim and appealing to a someone’s emotional responses seem to help. So too can instilling a sense of responsibility to help others, and an understanding that doing so is not futile.
All these observations are incredibly valuable. But I think there’s more to understanding why people don’t help others more, despite the fact they may believe in doing so in principle. A huge factor here is the behaviour of others. Most people appear to have a strong tendency not to want to help more than the other people around them.