Thanks for another very interesting post @honeybee. I find it interesting that people feel that they have to verbally deny self-interest like it is some sort of immoral behaviour. It is just natural to put oneself before others. That is how we have evolved and is critical to our survival. Self-interest does not necessarily mean total disregard for others or an absence of empathy. It just means we are prioritizing ourselves above others.

Self-interested people can still be altruistic. 'Good deeds' earn what is called psychic income. This is the 'feel good' feeling of helping others. 'Good deeds' also helps reduce negative feelings of guilt. So when someone does something nice for you, they are still acting in self-interest.

We can also look at enlightened self-interest. This involves helping others in order to help ourselves. People treat others with kindness so that will be treated with kindness in return. This also closely links to the golden rule of dong to others what you wish they will do in return for you. This behaviour is different from altruism but in both cases people are acting in self-interest.

Rational behaviour could also not exist in the absence of self-interest. In fact, most economic theories could not operate in the absence of self-interest. Rational behaviour is always a key assumption behind most of my work. I am always interested in trying to find irrational people.

@honeybee, have you ever encountered an irrational person?