Perception Bobblehead is a collectible item in Fallout 4 that permanently increases your perception by one. The description reads “Only through observation will you perceive weakness”.
If you’re looking for other bobbleheads, take a look at our Bobblehead Locations guide.
The perception bobblehead is in the Museum of Freedom in Concord. By following the main story, you’ll get to a quest where you need to help the Minutemen defend the museum from Raiders. Once you go up into the room where they are, you’ll find the collectible on a desk to the left of the door.