This is a brief followup thought to my earlier musings - http://mlpforums.com/blog/819/entry-11579-what-are-your-mane-3/

for clarifying why the focus on the six main characters for the show was such a smart idea regarding writing skill.

The point should be pretty much self-explanatory, so I won't comment on it.

Rarity = intellect - right brain hemisphere (synthetic, emotional, creative, imaginative, radiant)

Twilight Sparkle = intellect - left brain hemisphere (analytical, logical, scientific, rational, inquisitive)

Fluttershy = kind heart

Rainbow Dash = brave heart

Pinkie Pie = driving purpose - spiritual

Applejack = driving purpose - material