This is an awesome paper that speculates about alien life.
If you havent read this paper, check it out. Its not a difficult read. It uses science across multiple subjects to discuss what alien life be like.
It develops something called the scentience quotient. It is similar to an IQ. Basically, it observes the smallest, dumbest possible brain, as well as the smarted possible brain. The SQ (scentience quotient) ends up being on a scale of -70 to 50, with humans being at 13.
It goes on to point out that even a small difference in a SQ renders communication impossible. That humans, at 13,cant communicate with primates, at 9. So, an alien species at 16 might not be able to communicate with us because we are too stupid. Scary stuff!
The paper itself also delves inside various other properties of aliens. Do aliens have emotions? If they are like an octopus, or an insect cluster, propbably not. Aloens might not feel love because it might not have evolved. Love is a mammalian trait, because we have few offspring. If we dont love, our young will die.
It also goes on to mention other traits like differences in our value system. Do we value territory? Do we horde resources? Why? These are just two examples. I thought this was also interesting, as we dont often think that humans could have evolved some other way.