One of the most basic behaviors that I *think* applies to all mammals is motivation and reward. Rats are an excellent example of it because everyone is familiar with reward experiments with rats. For example, a rat will learn how to navigate mazes if there is a reward of some tasty treat at the end. They basically work for reward. Humans do the same thing. We navigate anything from the complexities of microcomputers to the mind-numbing assembly lines of tacos... all for reward.
I think this is a bit simplistic, at least until we clear up what exactly "reward" means.
Traditionally, for example, it was believed that dogs can be trained and learn tricks because of the rewards (ie. food treats) they get for performing a task.
Newer trends maintain that dogs
like to play, learn, work, associate with humans and eat; that they learn the skills and tricks because it is in their nature to do so, not because of the food treats.
In their natural environment, rats navigate mazes as well (albeit those mazes are made of soil, in walls etc.); it is in the rat's nature to navigate mazes.
Some studies suggest that people are motivated by rewards in the form of money only in manual labor, but not in intellectual tasks. In knowledge workers, bigger salaries do not necessarily correspond with improved productivity.
Communism specifically replaces the reward with "you are doing it for the good of the whole".
Indeed, some people sometimes take great pleasure in doing something for the good of the whole.
In fact, I think everyone enjoys doing something for the good of the whole every now and then.
But I do not think there is a person who would be eager to do something for the good of the whole all of the time.
Another problem is when people have differing ideas on what "the good of the whole" means, or when an understanding of it is imposed on them that they do not approve of, or a demand to do so 24/7/365.
I think Communism's flaw is in presuming that
everyone will
naturally have the same ideas
all the time.
This is a flaw that some other systems share.