XCOM: Enemy Unknown research and engineering guide

Interrogations/Autopsies

Whenever you defeat a new enemy type, your research team can perform an autopsy on the corpse after the battle. If you use the Arc Thrower item to capture the enemy alive, your research team can perform an interrogation (after which, they can perform an autopsy on the same subject).

In most cases, interrogations only give you research credit in a specific area. This credit simply speeds up research time related to said area. Interrogating a Sectoid Commander and an Ethereal provide additional rewards.

Note that “projects” refer to Foundry undertakings, and have no effect until you build a Foundry and spend the required resources to complete the project. Also, you cannot interrogate or stun robots, so don’t bother trying. 

Subject: Sectoid

Interrogation Result: Beam Weapon research credit
Autopsy Result: Unlocks Uplink Targeting (aim) for purchase for interceptors 

Subject: Sectoid Commander

Interrogation Result: Psionic research credit, Psi Armor prerequisite
Autopsy Result: Psi Lab available for construction 

Subject: Floater

Interrogation Result: Armor research credit
Autopsy Result: Unlocks Defense Matrix (dodge) for purchase for interceptors

Subject: Thin Man

Interrogation Result: UFO Technology research credit
Autopsy Result: Improved Medkit project (+50% to Medkit healing)

Subject: Chryssalid

Interrogation Result: None
Autopsy Result: Unlocks Chitin Plating item (+4 HP, reduces melee damage sustained)

Subject: Muton

Interrogation Result: Plasma Weapon research credit
Autopsy Result: Ammo Conservation project (all weapons require less frequent reloading)

Subject: Muton Beserker

Interrogation Result: Armor research credit
Autopsy Result: Unlocks Combat Stims item (temporarily reduces damage sustained by 50% & boosts stats/resistances)

Subject: Muton Elite

Interrogation Result: All weapon tech research credit
Autopsy Result: Plasma Weapon research credit

Subject: Heavy Floater

Interrogation Result: Flight research credit
Autopsy Result: Advanced Repair project (reduced repair times on S.H.I.V.s and interceptors)

Subject: Drone

Interrogation Result: None
Autopsy Result: Drone Capture project (use the Arc Thrower to control Drones in battle)

Subject: Cyberdisc

Interrogation Result: None
Autopsy Result: Unlocks UFO Tracking (boost) for purchase for interceptors

Subject: Sectopod

Interrogation Result: None
Autopsy Result: Advanced Construction project (accelerates vehicle and facility construction) 

Subject: Ethereal

Interrogation Result: All tech research credit, Psi Armor prerequisite
Autopsy Result: Unlocks Mind Shield item (increases defense vs Psi attacks)