Perception

Perception is one of the seven primary statistics in the SPECIAL system.

Fallout, Fallout 2, Fallout Tactics
Modifies: Sequence, ranged combat distance modifiers and the First Aid, Doctor, Lockpick, Traps and Pilot skills. A player character with higher Perception may notice things that allow them to open up new dialogue options on occasion. It also determines how far away they start from hostilities in random encounters.

Perception is required for many perks, notably PE 8 for Sniper in Fallout, Fallout 2, and Fallout Tactics.

Ways to increase Perception

 * In Fallout, Lorri in the Brotherhood of Steel's Lost Hills bunker can perform an operation to permanently increase Perception by 1, assuming it can be afforded.
 * In Fallout 2, Perception can be permanently raised by 1 with the Green memory module using ACE.
 * Also in Fallout 2, Perception can be temporarily raised by 1 with Jet.
 * In both Fallout and Fallout 2, Mentats can be used to temporarily raise Perception by 2.

Fallout 3
Modifies: Explosives, Lockpick and Energy Weapons skills

Perception determines how far away enemies can be detected on the compass (enemies show as red bars). When playing with a high Perception, it is possible to "sense" the enemies even before they come into view.

Having a high Perception can yield dialog options with some NPCs, such as Moira Brown, Mel and Machete.

Perception-based perks
The benefit of the Survival Expert perk is affected by what is said to Moira Brown after each portion of the Wasteland Survival Guide quest. Having a Perception of 7 yields relevant "smart" dialog options at the end of the Contract Radiation Sickness and Traversing a Mine Field objectives.

Ways to increase Perception

 * Permanent
 * Bobblehead - Perception (+1)
 * Ant Sight quest perk (+1)
 * Intense Training perk (+1)
 * No Weaknesses perk (will raise base to 5 if below 5)
 * Almost Perfect perk (will raise base to 9 if below 9)
 * Temporary
 * Armor and clothing
 * Maple's garb (+1)
 * Vance's longcoat outfit (+1)
 * Multiple hats give +1.
 * Chems
 * Mentats (+5)
 * Orange Mentats (+5)
 * Night Person perk (+2 between 6:00 PM and 6:00 AM)

Fallout: New Vegas
Modifies: Explosives, Lockpick and Energy Weapons skills

Again, Perception affects the distance at which the Courier is able to detect other creatures. It also factors into some conversations with some NPCs.

Ways to increase Perception

 * Permanent
 * Perception Implant available at the New Vegas medical clinic (+1)
 * Intense Training perk (+1)
 * Completing the quest The Apocalypse or The End will allow raising any one primary statistic by 1.
 * Temporary
 * Armor and clothing
 * Marked patrol armor (+1)
 * Stealth suit Mk II (+1)
 * Multiple types of headgear give +1.
 * Advanced riot gear helmet (+2)
 * Elite riot gear helmet (+2)
 * With the Four Eyes trait, glasses give +2 or +3.
 * Chems
 * Coyote tobacco chew (+1)
 * Mentats (+2)
 * Party Time Mentats (+2)
 * Drinks
 * Absinthe (+1 - +3 depending on Survival skill)
 * Nightstalker squeezin's with Mile in Their Shoes perk (+1)
 * Traits
 * Claustrophobia (+1 while outdoors, but -1 indoors)
 * Early Bird (+2 between 6am and 12pm, but -1 between 6pm and 6am)

Fallout 4
With the removal of skills in Fallout 4, Perception now directly affects accuracy in V.A.T.S., lockpicking, and stealing attempts.

The main difference from Fallout 3 and Fallout New Vegas is that perception no longer affects the distance at which enemies appear on the player's compass. Enemies do not appear on the compass in Fallout 4 unless they are looking for the player (Caution in sneak mode) or are fighting the player (Danger in sneak mode). Friendly NPCs do not appear on the compass at all.