Why being an Aspie may be part of the explanation:

1. I have recently come to realize that I have Asperger’s or as many prefer to say, I am an Aspie.  As I have read more about ASD traits and how they differ from NT standards, I see some possible correlation between being Aspie and having this extra awareness.
2. ASD folks are inwardly focused and live inside our heads.  We tend to have a lower body awareness and often much less social interaction.  To me this means that we are more intimately familiar with the landscape of our thought processes and so better able to pick out the extra signals.  Basically we just have our attention more focused in here rather than out there.
3. Aspies are not as aware of the social subtext around us.  The self limiting thought patterns referred to as group think provide NTs a way to maintain continuity with the social group to support cohesiveness.  While this process of accepting others beliefs as your own would clearly help solidify a person’s identity as a member of the group, it may also cause NTs to reject their own psi awareness if it would not be acceptable to the group.  ASDs don’t have a strong group think function or compulsion to agree with others.  This is one of our traits that causes the most social rejection.  In my experience, persisting in holding a view not supported by the group is a one way ticket to isolation.  Yet, I can say that I have a strong internal motivation to hold to my views in spite of opposition. Perhaps this gives me a certain fortitude in accepting an awareness that many would see as delusional.
4. ASDs are often noted for being overwhelmed by sensory input that NTs find comfortable.  If being ASD means that either the senses are more acute or as I suspect, the brain has fewer filters on the processing end, then perhaps we simply have more detailed data with which our subconscious can work to provide this extra awareness.
5. Many ASDs have some kind of special ability or gift, called savant abilities.  Perhaps the extra awareness is one of the possible savant abilities.
6. To raise an even more disturbing possibility, what if the extra awareness is the source of the autism spectrum.  If some integrate and assimilate the extra awareness better than others, they become high functioning or savant.  Those with overly strong empathy or telepathy could find the presence and interaction of others to be way too much input to process and shut down out of self preservation.  There is no one to teach them how to shut out the massive wave of thoughts and emotions from others.
7. Insight or creative thinking, finding associations and reaching conclusions without seeming to have worked through the problem.  Perhaps ASDs simply have a more complete integration of conscious and subconscious awareness.  So we are able to take note of information that for NTs would remain below the surface and be used only for basic intuition.
8. Brains are wired differently, but ASDs must have some kind of evolutionary advantage to have been retained.  In fact, some have proposed that we are moving toward a more Aspie-ish culture.  This in turn may be facilitating the emergence of an extra awareness in more people.