Intelligence

Intelligence is one of seven primary statistics in the SPECIAL system.
==Fallout, Fallout 2 and Fallout Tactics==
Modifies: the number of new skill points per level, numerous dialogue options, and many skills. 
One of the unique qualities of Fallout and Fallout 2 is the difference in gameplay caused by creating a low-Intelligence character. With a dimwitted player character, many non-player characters will simply shrug one off, while others will insult or even attack them. On the other hand, certain characters will take pity on the character's stumped intellect, and might treat them as innocent children. In some cases, where a character with normal vocabulary would need to persuade them or offer a service in exchange, these characters will often give the character gifts or allow them entrance in certain areas for free out of pity.
===Ways to increase Intelligence===
* In Fallout, the Brotherhood of Steel doctor in Lost Hills can perform an operation to permanently increase Intelligence by 1, assuming it can be afforded. The surgery can be done twice should the Vault Dweller have an Intelligence below 4 the first time it is performed.
* Intelligence can be raised permanently in Fallout 2 in three ways. First, by using ACE and the yellow memory module (+1). Second, by the Hubologist zeta scan/alignment in San Francisco (which can also provide +1 Luck, though the game may need save-scumming to get a bonus rather than a penalty). The last method is to take the Gain Intelligence Perk. The bonuses from these methods stack for a total of +3 Intelligence.
* In both Fallout 1 and 2, it can be increased by +1 for purposes of dialogue only, by taking the Smooth Talker perk.
* In both Fallout 1 and 2, Mentats can be used to temporarily raise Intelligence by 2.
* In Fallout 2, Intelligence can be temporarily raised by 1 point by the Purchase the Kesting Special quest given by Miss Kitty in the Cat's Paw brothel.
===Intelligence-based perks===
Perk 	Required	Level 	Additional Requirements 	Games
Brown Noser 	6 	2 	Charisma 5 	Fallout Tactics
Comprehension 	6 	3 	- 	Fallout 2, Fallout Tactics
Healer 	5 	3 	Perception 7, Agility 6, First Aid 40% 	Fallout, Fallout 2, Fallout Tactics
Smooth Talker 	4 	3 	- 	Fallout, Fallout 2
Survivalist 	6 	3 	Endurance 6, Outdoorsman 40% 	Fallout, Fallout 2, Fallout Tactics
Swift Learner 	4 	3 	- 	Fallout, Fallout 2, Fallout Tactics
Death Sense 	5 	4 	Deathclaws only 	Fallout Tactics
Educated 	6 	6 	- 	Fallout, Fallout 2, Fallout Tactics
Empathy 	5 	6 	Perception 7 	Fallout, Fallout 2
Rad Resistance 	4 	6 	Endurance 6 	Fallout, Fallout 2, Fallout Tactics
Sharpshooter 	6 	6 / 9 	Perception 7 	Fallout, Fallout 2, Fallout Tactics
Crazy Bomber 	6 	9 	Traps 60%, Unavailable to deathclaws and dogs	Fallout Tactics
Bonus Rate of Fire 	6 	9 / 15	Perception 6, Agility 7 	Fallout, Fallout 2, Fallout Tactics
Road Warrior 	6 	12 	Pilot 60%, Unavailable to deathclaws and dogs	Fallout Tactics
Autodoc Lowered Hit Points 	<4 	- 	Luck 2, Ride the Autodoc Rodeo 	Fallout 2
Autodoc Lowered Hit Points II	<4 	- 	Luck 1, Ride the Autodoc Rodeo 	Fallout 2
Autodoc Raised Hit Points 	<4 	- 	Luck 9, Ride the Autodoc Rodeo 	Fallout 2
Autodoc Raised Hit Points II 	<4 	- 	Luck 10, Ride the Autodoc Rodeo 	Fallout 2
==Fallout 3==
Modifies: Medicine, Repair, and Science skills, as well as the number of new skill points per level.
Intelligence determines the number of skill points earned per level up. The base number of skill points gained per level is 10 + INT. Skill points gained for raised Intelligence are not retroactive for past levels, so increasing this primary statistic early, if at all, is the best. Also, temporary modifiers to Intelligence (e.g. from Night Person or Button's wig) do not affect the number of skill points gained when leveling up, meaning the only impact of such modifiers is the +2 to the three Intelligence skills.
Value	Skill Points / Level	Skill Modifiers
1 	11 	Medicine +2, Repair +2, Science +2
2 	12 	Medicine +4, Repair +4, Science +4
3 	13 	Medicine +6, Repair +6, Science +6
4 	14 	Medicine +8, Repair +8, Science +8
5 	15 	Medicine +10, Repair +10, Science +10
6 	16 	Medicine +12, Repair +12, Science +12
7 	17 	Medicine +14, Repair +14, Science +14
8 	18 	Medicine +16, Repair +16, Science +16
9 	19 	Medicine +18, Repair +18, Science +18
10 	20 	Medicine +20, Repair +20, Science +20
===Intelligence-based perks===
Perk 	Requirement	Level	Additional Requirements
Daddy's Boy / Daddy's Girl	4 	2 	
Gun Nut 	4 	2 	Agility 4
Swift Learner 	4 	2 	
Comprehension 	4 	4 	
Educated 	4 	4 	
Entomologist 	4 	4 	Science 40
Nerd Rage! 	5 	10 	Science 50
Computer Whiz 	7 	18 	Science 70
Warmonger 	7 	26 	
===Ways to increase Intelligence===
;Permanent
* Bobblehead - Intelligence (+1)
* Intense Training perk (+1 per rank)
* No Weaknesses perk (will raise base to 5 if below 5.)
* Almost Perfect perk (will raise base to 9 if below 9.)
;Temporary
* Button's wig (+1)
* Lincoln's hat (+1)
* Berry Mentats (+5)
* Mentats (+5)
* Night Person perk (+2 between 6:00 PM and 6:00 AM)
===Notes===
If the Lone Wanderer has an Intelligence below 4, Dean Dewey will call them a "special needs" child and escort them to a classroom.
==Fallout: New Vegas==
Modifies: Medicine, Repair, and Science skills, as well as skill rate.
Intelligence affects skill points differently from how it did in Fallout 3. The number of skill points gained each level is based on the formula 10 + (0.5 * IN) per level, including level 1, where IN is the Courier's Intelligence. If one gets a non-whole number of skill points per level (e.g. 10.5 for INT 1) it will be saved for the next even level up (see Skill Rate).
===Intelligence-based perks===
Perk 	Requirement	Level	Additional Requirements
Retention 	5 	2 	—
Swift Learner 	4 	2 	—
Comprehension 	4 	4 	—
Educated 	4 	4 	—
Entomologist 	4 	4 	Survival 45
Pack Rat 	5 	8 	Barter 70
Nerd Rage! 	5 	10 	Science 50
Computer Whiz 	7 	18 	Science 70
Voracious Reader	7 	22 	—
Lessons Learned 	6 	26 	—
===Ways to increase Intelligence===
;Permanent
* Intelligence Implant available at the New Vegas medical clinic (+1)
* Intense Training perk (+1 per rank)
* Completing the quest The Apocalypse or The End will allow raising any one primary statistic by 1.
;Temporary
* Only permanent increases in Intelligence will increase points received when leveling up. While traits are relatively permanent (they cannot be changed at any time like the other temporary items), they will not increase level-up points.
* Armor and clothing
** Mad scientist scrubs, scientist scrubs, Dr. Klein's glasses (+1)
** Dr. Klein's scrubs, Dr. Mobius' scrubs, Dr. Mobius' glasses (+2)
* Chems
** Mentats (+2)
** Party Time Mentats (+2)
* Perks
** Meat of Champions (+1 for 60 seconds after eating a corpse.)
** Night Person (+2 between 6:00 PM and 6:00 AM)
* Traits
** Claustrophobia (+1 while outdoors, but -1 indoors)
** Early Bird (+2 between 6am and 12pm, but -1 between 6pm and 6am)
* Black coffee (+2 - +6 depending on Survival skill)
* "Smart Light" (+2 for 12 hours or until the player character uses the "Mood Lights")
===Ways to decrease Intelligence===
;Temporary
* Armor and clothing
** Lobotomite goggles, Lobotomite mask and goggles (-2)
* Consumables
** Alcohol (effects do not stack)
*** Absinthe, beer, Battle Brew, Jake Juice, Rum & Nuka, scotch, vodka, whiskey, wine (-1 to -3 depending on Survival skill)
*** Irradiated beer, irradiated scotch, irradiated whiskey (-1 to -3 depending on Survival skill)
*** Moonshine (-2)
*** Wasteland tequila (-2 to -6 depending on Survival skill)
*** Large wasteland tequila (-3 to -9 depending on Survival skill)
** Chems
*** Ant nectar (-2)
*** Ant queen pheromones, fire ant nectar (-3)
===Interactions that require Intelligence stat===
* An Intelligence of 3 or less will grant "special" reverse-Intelligence dialogue and actions. Instances of this include:
** During Come Fly With Me, the Courier can randomly mash the buttons on the launch control panel. The rockets will take off and rewards will be gained as though one passed the 55 Science check to properly input improved coordinates.
** When first meeting Ignacio Rivas at HELIOS One, respond "I is scientistic" after being asked about their reasons for visiting the power plant.
** When first meeting Ranger Milo, he refers to the Legionaries in Nelson as "Legion snakes," to which the Courier responds with the belief he meant actual snakes trained by the Legion, rather than him clearly speaking metaphorically.
** When first meeting Veronica, respond that they believe Brotherhood of Steel members can shoot lasers from their eyes after she asks how much one knows about them.
** When talking to Dog, ask about how he arrived at the Sierra Madre (without the use of exploits, this check must be passed to complete the challenge, The Whole Sad Story).
* An Intelligence of 2 or less will grant "extra special" reverse-Intelligence dialogue and actions. Instances of this include:
** When approached by the mobile facial recognition scanners on the third floor of REPCONN headquarters, the Courier can inadvertently guess the security password and roam the area without acquiring a keycard.
** When convincing Arcade Gannon to become a companion, he can be recruited out of pure sympathy by saying that Freeside is very complicated and a smart guy like him could help do stuff.Arcade's dialogue
* 5 Intelligence to correctly interpret Christine's thoughts that she can slow the detonation time of the explosive collar near radios when first nearing the vicinity of one.
* 6 Intelligence to convince Joe Cobb of the benefits in taking over Goodsprings and to allow the Courier to join his gang in attacking the town, triggering Run Goodsprings Run.
* 6 Intelligence to question how Emily Ortal was able to access the Strip during The Moon Comes Over the Tower.
* 6 Intelligence to see through the bounty hunter's facade as a traveling merchant during I Fought the Law.
* 6 Intelligence to offer a more convincing argument when Craig Boone asks why he should join the player after completing One for My Baby.
* 6 Intelligence to explain knowing that the Brotherhood of Steel is only hostile to those who use plasma or laser weaponry when questioned by Veronica about what they know about the group.
* 6 Intelligence to successfully question Orris about how he managed to kill four thugs with three bullets during G.I. Blues.
* 6 Intelligence to cook the imitation strange meat pie during Beyond the Beef (requires Philippe's recipes; bypasses Survival requirement).
* 6 Intelligence to make Frank Weathers admit to fleeing while the rest of his family were captured by Legion slavers during Left My Heart.
* 6 Intelligence to discuss with Lieutenant Romanowski about a connection between the new crop farms in Westside and the water shortage in the NCR pipelines during The White Wash.
* 6 Intelligence to successfully accuse Tom Anderson of stealing water from the NCR during The White Wash (bypasses needing to catch Hector in the act).
* 6 Intelligence to ask Arcade Gannon how he knows so much about REPCONN when entering their pre-War headquarters. Success will gain 1 of 5 required "history points" to trigger For Auld Lang Syne.
* 6 Intelligence to deduce from Dog that the Ghost people can be permanently killed through either dismemberment or disintegration.
* 6 Intelligence to successfully understand that Christine can make counterfeit Sierra Madre chips and can teach it as well, gaining the Coin Operator perk.
* 6 Intelligence to correctly understand why Christine has been ordered to man the Puesta del Sol switching station during Trigger the Gala Event instead of Dog or Dean Domino.
* 6 Intelligence to get Dr. Mobius to reveal that the Think Tank are still planning how to save themselves.
* 7 Intelligence to reassure Ignacio Rivas that the Courier's interest in HELIOS One is purely scientific during That Lucky Old Sun.
* 7 Intelligence to successfully counter Cass' sharp wit by asking if she even knows what a fish is herself.Cass' dialogue
* 7 Intelligence or 70 Speech to successfully talk Alice Hostetler down from killing her mother during Someone to Watch Over Me.
* 7 Intelligence to correctly deduce that Sergeant Bitter-Root is not being truthful about what he remembers from the Bitter Springs Massacre, getting him to reveal that he used the opportunity to settle some personal conflicts of his within the Great Khans.
* 7 Intelligence to impress Loyal by correctly assuming he planned a diversionary tactic against the NCR while the crashed B-29 is brought to Nellis during Volare!.
* 7 Intelligence to recite an override command to the mobile facial recognition scanners on the third floor of REPCONN headquarters (bypasses keycard requirement).
* 7 Intelligence to convince First Sergeant Astor that Private Edwards is not showing signs of becoming a feral ghoul and to allow him to return during We Will All Go Together.
* 7 Intelligence to placate Arcade Gannon after killing Anderson during The White Wash. Success will gain 1 of 5 required "history points" to trigger For Auld Lang Syne.
* 7 Intelligence to successfully convince Arcade that diverting HELIOS One's power equally across the whole New Vegas grid would be the best choice when he confronts the player after first talking to Fantastic during That Lucky Old Sun. Success will gain 1 of 5 required "history points" to trigger For Auld Lang Syne.
* 7 Intelligence to successfully suggest that Christine could use writing to communicate when first meeting her in Find Collar 12: Christine.
* 7 Intelligence to successfully impress Christine by understanding her miming a Brotherhood of Steel symbol when first meeting her in Find Collar 12: Christine.
* 7 Intelligence to correctly read the electrical diagram during Fires in the Sky, preventing God from blackmailing the Courier afterward (bypasses ghost harvester remains requirement).
* 7 Intelligence to display an understanding of the Dead Horses's tribal dialect when first entering Angel cave and talking to the Dead Horse Disciple of Canaan.
* 7 Intelligence to point out to Mobius that the names of the Think Tank all relate to loops (and to point out the incorrect spelling of Borous's name) during the quest Old World Blues.
* 7 Intelligence to correctly point out to Mobius that the three technologies needed to enter the Forbidden Zone were not chosen out of convenience during Old World Blues.
* 7 Intelligence to deduce that Ulysses took his name from the historical Ulysses rather than the mythical Ulysses, during The Job.
* 8 Intelligence to successfully convince Arcade that he should not be so judgmental of Caesar's Legion when no one knows anything of their past. Success will gain 2 of 5 required "history points" to trigger For Auld Lang Syne.
* 8 Intelligence to trick Silus into thinking the Courier is a Legion agent on a mission to kill him, leading to Silus revealing Caesar's brain tumor and hinting towards the truth about Ronald Curtis during I Put a Spell on You.
* 8 Intelligence to discuss with Dr. Klein about how the Sink personality chips were scattered across Big MT by Dr. Mobius during Welcome to the Big Empty.
* 9 Intelligence to completely resolve the matter of Doctor 0's name spelling and secure him as 1 of 3 required "votes" to make Dr. Klein stand down peacefully during Old World Blues (7 Intelligence results in a partial resolution that does not gain 0's required vote).
===Level names and statistics===
Value	Name 	Skill Points	Skill Modifiers
1 	Sub-brick 	10.5 	Medicine/Repair/Science +2
2 	Vegetable 	11 	Medicine/Repair/Science +4
3 	Cretin 	11.5 	Medicine/Repair/Science +6
4 	Knucklehead 	12 	Medicine/Repair/Science +8
5 	Knowledgeable	12.5 	Medicine/Repair/Science +10
6 	Gifted 	13 	Medicine/Repair/Science +12
7 	Smartypants 	13.5 	Medicine/Repair/Science +14
8 	Know-it-all 	14 	Medicine/Repair/Science +16
9 	Genius 	14.5 	Medicine/Repair/Science +18
10 	Omniscient 	15 	Medicine/Repair/Science +20
==Fallout 4==
Unlike in previous games, Intelligence has no effect on skills, since Fallout 4 lacks a separate set of scores for skills. Instead, a higher Intelligence, in addition to unlocking higher perks in the Intelligence category, will increase the amount of experience the player character earns from all sources.
The experience multiplier linearly increases from 103.33% (1 Intelligence) to 133.3% (10 Intelligence).minusra, I tested Intelligence, Idiot Savant, and experience gain in general; I performed over 5000 actions. Here's the results., reddit In other words, it increases XP gains by 3.33% per INT. It continues increasing if Intelligence is brought higher than 10. In math terms:
:{\it XP}_{\rm Final} = {\it XP}_{\rm Base}\times \left(1 + \frac{{\it Intelligence} \times 3.33}{100}\right)author unknown, Idiot Savant table and graph, Google sheets
A higher Intelligence also reduces the number of words that are displayed while hacking a terminal; for example, at an Intelligence of 10 or higher with a Science bobblehead, it almost becomes trivial to brute-force most hacking sessions.
===Intelligence-based perks===
Perk 	Intelligence required
V.A.N.S. 	1
Medic 	2
Gun Nut 	3
Hacker 	4
Scrapper 	5
Science! 	6
Chemist 	7
Robotics Expert 	8
Nuclear Physicist	9
Nerd Rage! 	10
===Ways to increase Intelligence===
;Permanent
*Level (+1)
*Intelligence bobblehead (+1)
*You're SPECIAL! book (+1)
;Temporary
=== Ways to decrease Intelligence===
; Permanent
* Addictions
**Daddy-O (-1)
**X-cell (-1)
;Temporary
*Drinks (All of them are considered alcohol and therefore override each other's INT decrease)
**Beer (-1)
**Bobrov's Best moonshine (-1)
** Bourbon (-1)
**Dirty Wastelander (-2)
**Gwinnett stout (and other Gwinett variants) (-1)
**Ice cold beer (-1)
**Ice cold Gwinnett stout (and other Ice cold Gwinett variants) (-1)
**Poisoned wine (-1)
**Rum (-1)
**Vodka (-1)
**Whiskey (-1)
** Wine (-1)
===Intelligence in quests and exploration ===
*The Last Voyage of the U.S.S. Constitution has multiple intelligence checks that can speed up progression through the quest. Instead of replacing components, the player character can repair them instead. This strategy applies to the replacement of the wires (requiring an Intelligence of 5) and radio antenna (with a score of 9 INT).
*When romancing Magnolia, she may compliment the player character's Intelligence if the score is their highest SPECIAL attribute.
* When repairing the decontamination system in Ablutions, an INT of 7 or higher can be used to make the decontamination arches remove radiation.
==Fallout 76==
Modifies: Experience yield, scrapping yield, item condition and durability, ability to hack terminals, number of duds when hacking terminals
=== Effects on experience yield===
Like Fallout 4, raising Intelligence increases experience gained. Each Intelligence point increases experience gained by 2.072%. With the use of buffs and equipment, an Intelligence of at least 81 (which would increase the player's experience by 167.832%) is possible. Under ideal circumstances, stacked with other XP buffs during a Double XP weekend, each basic enemy could yield over 4,000 experience points.
===Effects on scrapping yield===
A higher level of Intelligence increases the return from scrapping items.
Intelligence Level	Scrapping Yield
1 	+0%
2 	+20%
3 	+33%
4 	+40%
5 	+46%
6 	+50%
7 	+53%
8 	+56%
9 	+58%
10 	+60%
11 	+61%
12 	+62%
13 	+64%
14 	+65%
15 	+66%
===Effects on crafting ===
At an Intelligence of 1, there is a +0% crafted item condition bonus. Each additional level of Intelligence increases this condition bonus by +5%, except for the jump from Intelligence = 4 to Intelligence = 5, where the bonus increases by +10%. At the maximum Intelligence of 15, the crafted item condition bonus is +75%.
===Intelligence-based perks===
Name 	Level	Rank	Description
Armorer 	15 	1 	You can now craft advanced armor mods. (Plans Required)
Armorer 	15 	2 	Crafting armor now costs fewer materials.
Armorer 	15 	3 	Your crafted armor has improved durability.
Batteries Included	28 	1 	Energy weapon ammo weighs 30% less.
Batteries Included	28 	2 	Energy weapon ammo weighs 60% less.
Batteries Included	28 	3 	Energy weapon ammo weighs 90% less.
Chemist 	34 	1 	You get double the quantity when you craft chems!
Contractor 	18 	1 	Crafting workshop items now costs 25% fewer materials.
Contractor 	18 	2 	Crafting workshop items now costs 50% fewer materials.
Demolition Expert 	10 	1 	Your explosives do +20% damage
Demolition Expert 	10 	2 	Your explosives do +30% damage
Demolition Expert 	10 	3 	Your explosives do +40% damage
Demolition Expert 	10 	4 	Your explosives do +50% damage
Demolition Expert 	10 	5 	Your explosives do +60% damage
Expert Hacker 	22 	1 	Gain +1 hacking skill, and terminal lock-out time is reduced.
First Aid 	2 	1 	Stimpaks restore 15% more lost Health.
First Aid 	2 	2 	Stimpaks restore 30% more lost Health.
First Aid 	2 	3 	Stimpaks restore 45% more lost Health.
Fix It Good 	27 	1 	You can repair armor and Power Armor to 130% of normal maximum condition.
Fix It Good 	27 	2 	You can repair armor and Power Armor to 160% of normal maximum condition.
Fix It Good 	27 	3 	You can repair armor and Power Armor to 200% of normal maximum condition.
Gunsmith 	11 	1 	Guns break 10% slower and you can now craft Tier 1 guns (Plans required).
Gunsmith 	11 	2 	Guns break 20% slower and you can now craft Tier 2 guns (Plans required).
Gunsmith 	11 	3 	Guns break 30% slower and you can now craft Tier 3 guns (Plans required).
Gunsmith 	11 	4 	Guns break 40% slower and you can now craft Tier 4 guns (Plans required).
Gunsmith 	11 	5 	Guns break 50% slower and you can now craft Tier 5 guns (Plans required).
Hacker 	4 	1 	Gain +1 hacking skill, and terminal lock-out time is reduced.
Licensed Plumber 	5 	1 	Your pipe weapons break 20% more slowly and are cheaper to repair.
Licensed Plumber 	5 	2 	Your pipe weapons break 40% more slowly and are cheaper to repair.
Licensed Plumber 	5 	3 	Your pipe weapons break 60% more slowly and are cheaper to repair.
Makeshift Warrior 	9 	1 	Melee weapons break 10% slower and you can craft Tier 1 melee weapons. (Plans required)
Makeshift Warrior 	9 	2 	Melee weapons break 20% slower and you can craft Tier 2 melee weapons. (Plans required)
Makeshift Warrior 	9 	3 	Melee weapons break 30% slower and you can craft Tier 3 melee weapons. (Plans required)
Makeshift Warrior 	9 	4 	Melee weapons break 40% slower and you can craft Tier 4 melee weapons. (Plans required)
Makeshift Warrior 	9 	5 	Melee weapons break 50% slower and you can craft Tier 5 melee weapons. (Plans required)
Master Hacker 	38 	1 	Gain +1 hacking skill, and terminal lock-out time is reduced.
Nerd Rage! 	46 	1 	While below 20% Health, gain 20 Damage Resist, 10% damage and 15% AP regen.
Nerd Rage! 	46 	2 	While below 20% Health, gain 30 Damage Resist, 15% damage and 15% AP regen.
Nerd Rage! 	46 	3 	While below 20% Health, gain 40 Damage Resist, 20% damage and 15% AP regen.
Pharmacist 	6 	1 	RadAway removes 30% more radiation.
Pharmacist 	6 	2 	RadAway removes 60% more radiation.
Pharmacist 	6 	3 	RadAway removes twice as much radiation.
Portable Power 	49 	1 	All Power Armor parts and chassis weights are reduced by 25%.
Portable Power 	49 	2 	All Power Armor parts and chassis weights are reduced by 50%.
Portable Power 	49 	3 	All Power Armor parts and chassis weights are reduced by 75%.
Power Smith 	41 	1 	You can now craft advanced Power Armor mods. (Plans required)
Power Smith 	41 	2 	Crafting Power Armor now cost fewer materials.
Power Smith 	41 	3 	Your crafted Power Armor now has improved durability.
Power Patcher 	44 	1 	Your Power Armor breaks 20% more slowly and is cheaper to repair.
Power Patcher 	44 	2 	Your Power Armor breaks 40% more slowly and is cheaper to repair.
Power Patcher 	44 	3 	Your Power Armor breaks 60% more slowly and is cheaper to repair.
Power User 	50 	1 	Fusion Cores now last 30% longer.
Power User 	50 	2 	Fusion Cores now last 60% longer.
Power User 	50 	3 	Fusion Core duration is now doubled.
Robotics Expert 	48 	1 	Hack an enemy robot for a 25% chance to pacify it.
Robotics Expert 	48 	2 	Hack an enemy robot for a 50% chance to pacify it.
Robotics Expert 	48 	3 	Hack an enemy robot for a 75% chance to pacify it.
Science 	20 	1 	You can now craft energy guns. (Plans required)
Science 	20 	2 	You can craft Rank 1 energy gun mods. (Plans required
Science Expert 	31 	1 	You can craft Rank 2 energy gun mods. (Plans required)
Science Expert 	31 	2 	Crafting energy guns now costs fewer materials.
Science Master 	43 	1 	You can craft Rank 3 energy gun mods. (Plans required)
Science Master 	43 	2 	Your crafted energy guns have improved durability.
Scrapper 	13 	1 	Obtain more components when you scrap weapons and armor.
Stabilized 	36 	1 	In Power Armor, heavy guns gain more accuracy and ignore 15% armor.
Stabilized 	36 	2 	In Power Armor, heavy guns gain even more accuracy and ignore 30% armor.
Stabilized 	36 	3 	In Power Armor, heavy guns gain excellent accuracy and ignore 45% armor.
Weapon Artisan 	40 	1 	You can repair any weapon to 130% of normal maximum condition.
Weapon Artisan 	40 	2 	You can repair any weapon to 160% of normal maximum condition.
Weapon Artisan 	40 	3 	You can repair any weapon to 200% of normal maximum condition.
Wrecking Ball 	29 	1 	You deal +40% damage to workshop objects.
Wrecking Ball 	29 	2 	You deal +80% damage to workshop objects.
Wrecking Ball 	29 	3 	You deal +120% damage to workshop objects.
===Ways to increase Intelligence===
Note that all stat boosts in Fallout 76 are temporary. 
*Bobblehead: Intelligence (+2 for 1 hour or 2 hours with Curator)
* Armor and apparel:
**"Casual" underarmor with a treated lining mod (+1)
** "Casual" underarmor with a resistant lining mod (+1)
**"Vault suit" underarmor with a resistant lining mod (+2)
**"Casual" underarmor with a protective lining mod (+1)
**"Vault suit" underarmor with a protective lining mod (+2)
**"Casual" underarmor with a shielded lining mod (+3)
**"Vault suit" underarmor with a shielded lining mod (+2)
**Conspiracy suit with shielded lining (+2)
**Power armor helmets with internal database mod
*Legendary Effects:
**Intelligence (+1)
**Unyielding (+3 to all SPECIAL except Endurance at under 20% HP, up to potential +15 INT with five pieces)
** Unyielding power armor is legacy content
*Mutations: 
**Egg Head (+6, possibly more with Strange in Numbers)
**Herd Mentality (+2 if grouped, -2 if solo)
*Perks:
**Night Person (+1 to +3 during the night)
*Consumables:
**Food:
***Brain bombs (+3)
***Brain fungus soup (+2)
*** Broiled scorchbeast brain (+3)
*** Owlet nuggets (+1)
***Scorchbeast mixed meat stew (+1)
**Drinks:
***Simple aster tea (+1)
***Steeped aster tea (+2)
**Chems:
***Berry Mentats (+5)
***Daddy-O (+3)
***Mentats (+2)
*** X-cell (+2)
*Joining a Casual Public Group increases Intelligence by +1 at first, and +4 after being grouped with three other players for several minutes.
Additionally, the Marsupial mutation reduces INT by 4, which can be reduced to -1 with Class Freak.
==Fallout Shelter==
Intelligence affects how efficient a dweller is while working in the medbay and science lab facilities. A dweller's Intelligence can be increased by assigning them to the classroom.
==Fallout: The Board Game==
Unlike other games, Intelligence is not treated as a variable ranging from 1 to 10, but instead as a token that can be obtained at the start or when leveling up. A player character with the Intelligence token gets free rerolls during certain tests, as well as during fights if equipped with an Intelligence-based weapon. They can also recruit certain companions from the shop.
The Brotherhood Outcast player character always begins the game with Intelligence. Any player character wearing the lab coat gains one hit during an Intelligence test. During any Intelligence test, Mentats can be used to gain one free hit.
===Intelligence-based perks===
*Gun Nut
* Nerd Rage!
*Swift Learner
===Intelligence-based weapons===
*Alien blaster (x2)
*Fat Man
*Laser rifle
*Plasma gun
=== Companions requiring Intelligence=== 
*Loadlifter
*Protectron
==Low Intelligence characters==
In almost all of the games in the Fallout series, setting the player character's intelligence to a very low level will result in the player character having the mentality of a very young child. This results in some quite humorous differences when talking to NPCs: Dialogue options will generally be childish and immature, frequently marred with grammatical and spelling errors, an inability to understand basic concepts, non-sequiturs, caveman-like speech, and baby talk. NPC reactions to the player character's unintelligence can vary from taking pity on them to outright mocking them.
===Fallout and Fallout 2===
When the player character in Fallout and Fallout 2 has less than 4 Intelligence, the biggest change in gameplay is undoubtedly the dialogue. Upon reaching Shady Sands, the villagers take pity on the Vault Dweller, and Aradesh will simply shrug them off. The best they can speak is half-word sentences or gibberish. This makes for some unique dialogue with the overseer while attempting to return the water chip.
It is possible to complete the game as an idiot, but most side quests are impossible to do, and character growth is limited, as is the story involvement possible - while it is possible to bumble through the main quests, almost all plot details and background information will be left missing. Furthermore, due to limited-at-best non-player character interaction, almost all side quests are unavailable.
Talius at the Boneyard will gift a low Intelligence character with some mentats, and Darrel at the Lost Hills bunker gives them Rad-X. Additionally, during Dr. Lorri's surgeries, a Vault Dweller with low Intelligence will fittingly receive a 50% discount on the Intelligence boosting implant, lowering the price to 3000 caps. 
The only companion available to stupid characters is Dogmeat.
The real downside, though, is the nigh impossibility to do about 90% of the side quests. No one will talk to a moron or even give them the time of day.
In Fallout 2, the Chosen One may meet Torr, the "town simpleton of Klamath," who would normally give them a quest to help protect his brahmin against "the evil bugmen." If the player character has low Intelligence, however, he will appear to be highly intelligent as if being stupid has a culture and language of its own. Two flat-headed people can have a complete, thought-provoking, and fully articulated conversation between them.
Another person one may have an "intelligent" conversation with is AHS-9, who becomes able to understand what the Chosen One tries to say after the alignment, and gives the quest to kill the Shi Emperor.
At the Den, low Intelligence characters still have the option to become a Slaver, and they will still receive a reward from Becky for killing Metzger. Killing Metzger is also the only way for dim-witted characters to free Vic, and he will still be available as a potential companion regardless of Intelligence.
For idiot players, the quest Something strange is happening at the farm northeast of Modoc. Investigate and report back to Jo becomes much easier. It will be presented to them while talking with Jo at Modoc. If they agree, all they have to do is travel to the Ghost Farm and talk to Vegeir. It is followed by Deliver Slag message to Jo in Modoc. One will be rewarded with the location of the Gecko town, which Jo mistook for a G.E.C.K. They will also receive an additional reward for completing the quest Farrel has a rodent problem in his garden. Remove the infestation, a cookie.
At Vault City, Skeev will try and enslave a stupid Chosen One. If one allows it, they will trigger a brief cinematic at the Servant Allocation Center with Barkus, before being automatically transported to Vault 8. If the auto-doc in the courtyard has been repaired, then the unmarked quest Auto-Doc Rodeo becomes available. This quest gives 2 unique perks which are determined by ones Luck stat.
A stupid Chosen One will speak a unique stupid line after hitting Lumpy at Broken Hills with their Highwayman. This is interesting, as one will need to boost their Intelligence via the use of Mentats in order to purchase and repair the Highwayman first. The mutant sheriff of Broken Hills Marcus, may become provoked if insulted by a stupid character, which makes him turn hostile. 
When talking to Algernon in the basement of New Reno Arms, the Chosen One can start a childhood "cop and robbers" type dialog in which they accidentally "shoot" and kill him.
"Take care of Officer Jack" for Mira is a unique quest available only to player characters with an Intelligence stat of below 4 and a Strength stat of 7 or above. Also, the quest Retrieve Parts/Gain Access to Vault 15 is still available and one can still have a somewhat normal conversation with President Tandi at the NCR town. 
Gruthar allows the Chosen One to enter Vault 13 freely, after realizing that they are clearly mentally handicapped.
Low Intelligence characters are presented with an additional option when it comes to completing the Navarro quest You need to use a FOB to access the navigation computer. They can lie to the base commander's room guard after they are mistaken as clean up crew, allowing them entry to his room. Unique dialogue is also present while conversing with the sympathetic quartermaster.
A character with a low Intelligence is unable to gamble. When they observe a roulette table or a slot machine, the character will respond to it as a fun toy or an interactive character, respectively. Visiting a craps table will result in a dumb Chosen One commenting to the dealer that they "play craps in pants".
===Fallout 3===
In Fallout 3, there are conversation situations where characters with low Intelligence are granted other dialogue options, often relating to their low intellect. However, these options are few and far between, unlike the other Fallout games where one could play the entire game as a person without Intelligence. One instance is in Roosevelt Academy, where if the Lone Wanderer activates Dean Dewey while having an Intelligence below 4, he will deem them a "special needs" child, and escort them to a "proper room."
===Fallout: New Vegas===
In addition to alternative Intelligence checks, low Intelligence changes some dialogue options when speaking to vendors and non-player characters. For example, when speaking to Miguel at Miguel's Pawn Shop, the option to start trading is "Me buy things," and when speaking with Dr. Usanagi at the New Vegas medical clinic after she gives the Courier the initial description about implants they get the dialogue option "You sell plants, too?", which will cause her to re-explain the implants and suggest [the player character] take the implant to make them smarter. If taking her up on this deal, she will state that she thinks the Courier "could really benefit from it," and offer the implant at a discount.
In place of the gibberish of past games, however, the player character will simply not completely understand a conversation, confuse what someone is saying with something else entirely, or not understand what situation they are currently in. In the REPCONN headquarters, for example, a character with an IN of 1 or 2 can bypass a robot that demands a password by saying "ICE CREAM!" Normally, a Luck of at least 7 would be needed to guess this. All of the other low Intelligence dialogue options require Intelligence of 3 or less.
Low-Intelligence characters attempting to do the quest That Lucky Old Sun will be granted several unique dialogue options when conversing with Fantastic and Ignacio Rivas. An example is when informed about the hostilities between the Followers and the NCR, the Courier can ask, "Do Flowers and NCR bear play together?"
When first speaking to Ranger Milo he will inform the Courier that some "Legion snakes" are held up in Nelson, to which they can respond "Snakes are small. Why don't you just use a gun or whatever to shoot them." He will then call them a "special folk," and explain that they are not really snakes but "like snakes."
While helping Argyll in Nellis medical station while doing the quest Volare!, the Courier is given an option to "CHOP CHOP CHOP!" instead of giving him treatment. Ironically, the Courier actually saves the patient and Argyll comments on it, saying it was "dumb luck."
In Dead Money, the Courier will say "bye-bye, light person!" upon exiting dialogue with a hologram.
If the Courier's Intelligence stat is the most extreme (highest or lowest), Doc Mitchell will either compliment saying "maybe them bullets done your brain some good" (for highest) or apologize, stating he fixed up the Courier's head the best he could (for lowest).
===Fallout 76===
Similar to Fallout 3, low Intelligence checks are involved in situations where characters with low Intelligence are granted other dialogue options, often relating to their low intellect. Checks range from +4 to even negative Intelligence, going from -1 to -7. For example, while the player character goes to a bar with Leila Rahmani and is asked what they would like, a -1 intelligence check to ask the bartender for Nukashine is present.
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==Gallery==
FO4 Intelligence Loading Screen.png|FO4 VDSG
==Video==
thumb|left|320px|Fallout 4 Intelligence promotional video
==References==
Category:SPECIAL
Category:Fallout primary statistics
Category:Fallout 2 primary statistics
Category:Fallout 3 primary statistics
Category:Fallout: New Vegas primary statistics
Category:Fallout 4 primary statistics
Category:Fallout 76 primary statistics
Category:Fallout Tactics primary statistics
Category:Fallout: The Board Game primary statistics
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