The fifth attribute the Chief Elder mentions is "the Capacity to See Beyond".

Unlike the first four attributes that the Receiver of Memory must have - intelligence, integrity, courage, and wisdom - this attribute is impossible to describe, because it is beyond the comprehension of the ordinary population of the Community.  It is a gift that is found only rarely in an individual, and although Jonas has is aware of its presence, he is as yet unable to identify it.  All he knows is that sometimes, when he is looking at something, what he sees somehow changes.  This has happened a few times to Jonas, once when he tossed an apple to his friend Asher, once when he was looking at his other friend Fiona's hair, and now again just after the Chief Elder has mentioned it, as he is looking out across the crowd.  The same thing happens to the "sea of faces" before his eyes as had happened with the apple, a with Fiona's hair - for a brief moment it changes, then he blinks, and it is gone.

Jonas learns later that his Capacity to See Beyond is actually an ability to see color.  Everything in the Community has been reduced to such a level of sameness that color is no longer perceived.  Jonas, however, somehow has retained, or been given, the ability to see more deeply and clearly than everyone else.  This attribute has been identified by the Elders, and Jonas thus has been chosen to be the next Receiver of Memory (Chapter 8).