Only through observation will you perceive weakness.
Bobblehead - Perception is a Fallout 3 item, a Vault Boy bobblehead. It permanently improves the Lone Wanderer's Perception by 1, up to a maximum of 10.
Found in the Museum of Dave in the Republic of Dave, on a shelf on the right side of the museum.
Collectable perception bobblehead available from the Bethesda store.