Altruism is a general term for behavior that benefits others but not the actor herself. The definition is usually taken a step further to require behavior that comes at a cost to oneself. Altruism is the opposite of selfishness. It is distinguished from duty and loyalty and reciprocity.
In Freud's tripartite model of the self the three components are the id, the superego, and the ego. The id represents the unorganized part of the psyche in which are found the basic drives of the human animal (pleasure-seeking and pain-avoiding). This seat of the "instincts" is unconscious — we are affected by it but not aware of it explicitly.
In Freud's tripartite model of the self the three components are the id, the superego, and the ego. The superego represents the organized part of the psyche in which is found the perfectionistic control that opposes the id. The super-ego strives to act in a socially appropriate manner, whereas the id just wants instant self-gratification. In the context of this course, it represents the internalization of social controls.
Since humans are more or less equal is size and smarts, they don't tend to have natural hierarchies and so anyone of them is apt to attempt to take from any other at any time. Just when you think you are settled with something, someone will try to take it away.
An atavism is a trait from the evolutionary past that reappears in an organism. In early biological theories (e.g., Lombroso in late 19th century) of deviance it refers to "animal-like" traits (e.g., violence, greed, lack of cultivation) that civilized humans are thought to have lost but that show up in the "criminals among us." It's a logic that lets us think of humans as constantly evolving toward a better moral state but still having an explanation for why crime persists.
Differential association theory says that whom you associate with affects your values and behavior. If you more exposed to anti-social definitions, attitudes, and logics, then you will tend toward being delinquent. "Association" refers to social interaction — hanging out, interacting. The differential refers to the comparison between the fraction of your social world that orients you toward "the good" and the fraction that orients you toward "the bad."