Having emotions, and knowing that we are having emotions, are not quite the same thing. Without a developed consciousness (brain) that can recognize a sense of self ("I"), an organism does not know that it has emotions. It experiences emotions, and its emotions affect its behavior, but not at the level that you and I experience.
Where that knowledge about having emotions comes from, is the same place that the knowledge that we acquire about the world comes from. That is they both come from our developed conscious brain, that has the ability to recognize ourselves as individuals, and allows us to know that we as unique individuals are experiencing our own emotions.
Therefore, the answer to the question is that no, we were NOT capable of being human, compassionate, loving, generous, creative etc. before we learnt to accumulate knowledge, because before we were able to KNOW, we were not able to make value judgments based on our emotions, because we didn't KNOW that our emotions were "ours". Before we humans, developed a brain that was capable of saying "I", we were not any different from animals, that act on instinct, and behave based on their sense of survival. Ofcourse in many ways, that is still true of humans.
This evolutionary development of the human brain and consciousness did not happen overnight, but rather, over the course of millions of years. There was never a single point in time, when we suddenly acquired a "soul", or developed our conscious sense of self. It happened gradually and incrimentally over a long period of time.
That is why scientists reject the religious notion of "immortal soul", that is supposed to belong exclusively to humans.