Logical (3.5e Trait)
From D&D Wiki
You are very understanding in math and science, though the arts of society elude you.
Benefit: You gain +2 to all knowledge checks.
Drawback: You get -2 to all Cha based checks.
Roleplaying Ideas: You are very precise about all items, and tend to be all knowing in areas of your expertise. You chose your cold books over the warm touch of living creatures.