Jonas is different from the rest of his community because he has light eyes and the Capacity to See Beyond.
In Jonas’s community, most people do not question the way things are. Things just are as they are, and people accept that they have always been that way. Jonas is a little different. He has light colored eyes, which are also directly related to the other way he is different: Jonas has the Capacity to See Beyond. For this reason, he is chosen as the Receiver of Memory.
Almost every citizen in the community had dark eyes. His parents did, and Lily did, and so did all of his group members and friends. But there were a few exceptions: Jonas himself, and a female Five who he had noticed had the different, lighter eyes. (Ch. 3)
During his Ceremony of Twelve, the Chief Elder explains why Jonas is different. She does not mention that he has light-colored eyes, which are very rare in his community and give him a deep and thoughtful look. She does mention that he has several special traits that make him perfect to be the next Receiver of Memory.
"He has shown all of the qualities that a Receiver must have."
With her hand still firmly on his shoulder, the Chief Elder listed the qualities. (Ch. 8)
Jonas has several traits that make him unique in his community. The Chief Elder lists them as intelligence, integrity, courage, and wisdom. The last trait is the Capacity to See Beyond. Jonas is not really wise yet, but he has the ability to become wise, because he is already thoughtful.
Jonas is different from other members of his community because he notices things around him. After he begins his training, his observations are colored by his changed perception. The memories have changed him, and made him even more different from the others in his community.