Psychologists define altruism as a motivational state with the goal of increasing another's welfare. Psychological altruism is contrasted with psychological egoism, which refers to the motivation to increase one's own welfare. When one does a job that is beneficial for other without any expectations about getting a pay back. We all can think back and try to remind if we have helped somebody when we were kids. Letting others to play with your toy, eat a piece of your candy, etc. All this acts could be classified as altruistic if we were not trying to get something in return for.

Remember, however, that altruism involves true selflessness. While all altruisms acts are prosocial, not all prosocial behaviors are altruistic. For example, we might help others for a variety of reasons such as guilt, obligation, duty or even for rewards. In my opinion, this opposes a number of different explanations for why altruism exists that psychologists have suggested. Here are they:
Neurological Reasons: Altruism activates reward centers in the brain. Neurobiologists have found that when engaged in an altruistic act, the pleasure centers of the brain become active. So, we get pleasure as a reward for our altruistic actions. Therefore they are not altruistic any more but prosocial.

Cognitive Reasons: While the definition of altruism involves doing for others without reward, there may still be cognitive incentives that are not obvious. For example, we might help others to relieve out own distress or because being kind to others upholds our view of ourselves as kind, empathetic people. It means we're not doing something for other person, but our own self.

Biological Reasons: We may be more altruistic towards those we are related to because it increases the odds that our blood relations will survives and transmit their genes to future generations. One should say that while helping someone we don't see him/her as an individual.

The major difference between prosocial behavior and altruism is the goals of these activities. Prosocial behavior may be directed to get something back. So we can say the goal of prosocial activity is to get something in exchange for. Since altruistic behavior's aim is to help other people without any expectation of getting a payback.

Our parents show us that prosocial actions are accepted and bestirred. This of course is very nice of them. Lessons like that help children to get used to the basic regulations of the society. I was often told to share my candy to other kids, so they would give me some later. Even if I did not realize why was I supposed to do so I used to share my stuff with others. So do most of others (whoever does not gets punishment from society). We all know that kids always ask the question "why?" Parents never answer that you just have to do it without anything in exchange for (even if they say this answer will not satisfy child's curiosity). Parents say we have to do so because we'll get something nice in return for. It proves that we learn prosocial behavior in our early ages, but not altruism. I would suggest an idea that it is impossible to teach altruistic behavior. Since this kind of actions are not premeditated, they are impulsive.

In conclusion, actions whether they are prosocial or altruistic helps society to change for better. Maybe altruism by itself does not really exist, but in combination with prosocial behavior it still is a positive thing.

About Author / Additional Info:
I study Psychology at Ivane Javakhishvili Tbilisi State University.