In the Fifties, a desk lamp in an interrogation room would be turned so that a perp would have the light in his eyes and stern questions would come out of the dark as sweat poured down his face. Sometimes, there might be a nice, cool glass of water just out of the perp's reach to "aid" his concentration. This was Perp Sweating.
Two character types on whom Perp Sweating almost never works include The Sociopath and people with Asperger's Syndrome: two totally different types of people, both on different levels of communication than you. The Sociopath will be two steps ahead of you and retaliate with a Hannibal Lecture. An autistic person will be seven or eight steps behind (or ahead, depending on how they function), and get confused by subtle questions, annoyed by a Good Cop/Bad Cop routine, and clam up if you start lying to them. The savvy ones will Be as Unhelpful as Possible to get back at you. Either way you're going to have to rethink your techniques with them.
One major problem with Perp Sweating is that it is often done in an effort to elicit a confession in the absence of evidence actually proving the person's guilt. In other words, the interrogator is assuming the questioned individual's guilt even without a concrete reason. At best, this can be called poor investigative technique and at worst, it can be called a violation of the principle that everyone is presumed innocent until proven guilty.
See also Perry Mason, Columbo. But beware any attempt to try this on the Psycho for Hire, lest you be reduced to tears by a Hannibal Lecture. Also, just 'cuz it happens on teevee doesn't mean it's legal — depictions in media often skip the suspect's Miranda Rights or similar warnings (though this can be excused if the setting is in jurisdictions that lack these rights).
- Be as Unhelpful as Possible
- Bluffing the Authorities
- Bluffing the Murderer
- Confess to a Lesser Crime
- Don't Answer That
- Enhanced Interrogation Techniques
- Exasperated Perp
- False Roulette
- Food Interrogation
- Forced to Watch
- Good Cop/Bad Cop
- High-Altitude Interrogation
- I Never Said It Was Poison
- Interrogation by Vandalism
- Jack Bauer Interrogation Technique
- Lying to the Perp
- The Perry Mason Method
- Prisoner's Dilemma
- Rabid Cop
- Rats in a Box
- Real Stitches for Fake Snitches (when threatened)
- Torture for Fun and Information
- Truth Serums
- Twerp Sweating (not actually a subtrope, but related)
- Vandalism Backfire
- Virtual Reality Interrogation
- We Have Ways of Making You Talk
- Whispered Threat
- Parodied in the popular "Got Milk?" commercials. In one commercial, a cop interrogates a suspect while placing a package of snack cakes on the table. When the suspect notices the snack cakes, the cop says, "Go ahead, have 'em." The suspect wolfs down the cakes while the cop pours a glass of milk. "Now then," he says as he places the glass in front of the suspect, "We can do this the easy way, or we can do this..." He suddenly slides the glass out of the suspect's reach. "The hard way." The suspect, not having any milk to wash down the snack cakes, gulps loudly.
- Ninja Nonsense of all series, has one of these when Onsokumaru questions Miyabi about the boy she has a crush on.
- An early episode of Dominion Tank Police has the force doing it as a game show, with the perp strapped to a spinning knife-throwing target, with a hand grenade stuck in his mouth. Oh, and Leona emceeing in a Playboy Bunny outfit.
- In Nightwalker, Yayoi is subjected to this treatment by unseen superiors in her own anti-demon Men in Black agency after they learn that she's been hiring a vampire to help crack cases.
- Sid plays at this with Woody in Toy Story before launching into We Have Ways of Making You Talk.
- In Toy Story 3, Buzz is being interrogated by the mob under a big bright light.
- Kent Mansley in The Iron Giant does this to Hogarth.
- The Incredibles short "Jack-Jack Attack" starts with a black screen with Kari's voice complaining that it's too dark. Suddenly a light gets shone in her eyes by Rick Dicker. "Wow, and now it's too bright!"
- Incredibles 2 also starts with this, with Rick interrogating Tony Rydinger after he saw Violet in her superhero costume.
- L.A. Confidential had such a successful Perp Sweating that the men being held were not only in tears, but actually crapping themselves.
- In the 1990 film Dick Tracy, Dustin Hoffman's character Mumbles is subjected to a deliberately over-the-top example of this.
- Cast a Deadly Spell. When Lovecraft refuses to cooperate with the police, his friend Lieutenant Bradbury turns a bright light in his face and starts questioning him.
- The Matrix has Agent Smith as a Smug Snake with a high stack of annotated papers and manila folders, the props used in the old "We Know Everything" bit, implying that the authorities have his permanent record, and that it really does contain everything you've ever done wrong. It was less than effective than they were used to when they applied it to Neo, however.
- In Mystery of the Wax Museum, cops keep questioning Darcy, and he spills the beans on Ivan's operation as he starts going cold turkey from his drug addiction.
- The Action Hero's Handbook — "How to Interrogate a Suspect" discusses common perp sweating techniques and how to tell if a suspect has something to hide.
- The Night Mayor is set in a virtual reality realm based on Film Noir movies. At one point, the protagonist is arrested for a murder he didn't commit and given an interrogation with all the trimmings, including the desk lamp and the Good Cop/Bad Cop duo.
- German novel The Pledge has a character that found a girls corpse become victim to this as the police and public were looking for a scapegoat. It works so well that he succumbs to the pressure, confesses the murder he never committed and then kills himself in his cell.
- Subverted/Inverted/Monkeywrenched in Law & Order: Special Victims Unit, when they had the killer, but they need to find his latest kidnap victim before she runs out of air. He doesn't drink anything (can't get DNA), doesn't need to poop (can't "trade" him a bathroom break for info), doesn't give them any information, can't be intimidated by even Elliot's best efforts, and they can only hold him for so long. He's a copycat killer, so when The Profiler Dr. Huang looks at his crimes, he realized that the victims—who, like the original killer, were all mothers—were never raped. They bring in his mother, who reveals that he's a disappointment to her, and he's afraid of the dark. There happens to be a closet down the hall. This is arguably torture from a legal perspective, but they care more about saving the victim than getting a conviction by that point.
- Subverted in another episode where the suspect is a U.S. Marine. Olivia wants to put him in the interrogation room and sweat him but Finn rejects that plan as marines are explicitly trained to resist interrogation and from people with far less restraint than the NYPD. Later when Olivia does try Perp Sweating, all of her tactics fail to crack the suspect. Olivia even calls him a textbook sociopath when pictures of the victim's body fail to faze him. Finn has to point out that four combat tours in Iraq would leave anyone jaded.
- In Law & Order: Criminal Intent, Goren is very good at this.
- Leroy Jethro Gibbs is famous for his skill at this. (So, of course, is Tony.) And when Gibbs can't crack them, sometimes he lets Ziva have a turn. Failing all else... off to see the Creepy Mortician.
- Gibbs also has a unique advantage: he often outranks any military man he's perp-sweating, forcing them to be more truthful.
- In one episode Tony and McGee do this by using cookies. Their target is a silent mercenary type and nothing they tried fazed him. So, they offered him cookies As they rattled over what some set of numbers could be, a breath of surprise and recognition he could normally control becomes an obvious cough with all the cookies in his mouth. He gets very flustered as they piece together the information from his denials.
- Subverted in an episode of Seinfeld where Newman interrogates Jerry, but sits himself under the hot lamp instead of Jerry. Newman gushes sweat while Jerry sits comfortably and sips a refreshing soda.
- In Veronica Mars, Keith Mars seems to enjoy doing this.
- In Stargate SG-1, Teal'c can make anyone talk by just staring at them.
- So can Garak in Star Trek: Deep Space Nine. He once describes how he interrogated a guy by staring at him... for three hours. In the same episode, Garak presents a more straightforward example: using a device that prevents Odo from reverting to his liquid form as his biology requires; making him progressively more uncomfortable the longer he holds back the information Garak wants. It eventually crosses the line into outright torture.
- Seen in the pilot episode of Detroit 1-8-7. After a suspect feels smug at having frustrated the rookie detective, the rookie's senior partner goes into the room, sits down, and just stares.
- Happens to a female IMF agent in an episode of Mission: Impossible, where the team are trying to stop the Banana Republic of Terra Nueva invading democratic San Cristobal. The fact that she's wearing a towel also clearly implies she's been strip-searched. They find the information they are supposed to find microdots in her contact lenses.
- Power Rangers S.P.D. once did this in the Rangers' own typical Bunny-Ears Lawyer way, subjecting the poor perp to the Pink Ranger's hit single Me and the Green Ranger's stream-of-conscious rambling until he talked.
- Humorously inverted in Firefly. in one scene Jayne makes the interrogator start to loose his cool by staring at him from a slouching posture with a slight smirk and completely ignoring any questions. This is made even more hilarious by the scene interspersed with shots of the Alliance search party finding Jayne's impressive (one might even say ludicrous) arsenal.
- On Las Vegas, a snarky casino guest who's being questioned by Ed about a robbery pulls a lamp around to shine in his own eyes, then quips that he's ready for the interrogation now.
- Batman (1966). In the episode "The Dead Ringers", Commissioner Gordon and Chief O'Hara put Harry (Chandel's Evil Twin brother) under a bright light while questioning him.
- Buffy the Vampire Slayer. Mild and geeky Willow enjoys interrogating Jonathan (with desk lamp) when the Scoobies suspect him of murder in "Go Fish". The gag is repeated again in "Earshot".
- Criminal Minds used a lot of interrogation in its early seasons, as, oftentimes, the team would have a completed profile of the UnSub but little in the way of actual physical evidence- thus requiring a confession.
- Played for Laughs in one episode of Black Books, when Bernard, Manny and Fran are getting ready to go on holiday. Bernard and Manny tie Fran to a chair with a glass of wine just out of reach, turn a lamp so that the light shines right in her face... and confront her with the fact that she has packed her suitcase full of shoes and nothing else.
Manny: We're here to help you.Fran: You don't understand!Bernard: (opens the suitcase dramatically, revealing the shoes) We understand that you're ill.
- Blue Bloods does a literal example of this in the episode "Immunity". An Argentinian diplomat's son suspected of being a serial rapist targeting college girls, and he is protected by diplomatic immunity. He's invited to be questioned at the precinct. Danny deliberately has the A/C unit in the interrogation room shut off, so the guy starts to sweat. Then, after he leaves, the crime scene techs collect the guy's DNA, which is used to nail him (the guy's father is convinced to waive diplomatic immunity, as DNA evidence also proves he's guilty of a similar crime in Argentina, where immunity would not apply and prisons are much worse).
- Angie Tribeca is a cop show spoof, so of course they're going to have some fun with this trope. Tanner barraging a suspect with a hurricane of board game puns (you're looking at Life, you're in a lot of Trouble, you'll be Sorry, etc.) is an excellent example of how this usually goes. In another episode, Angie and Jay also quite literally sweat a perp by turning the interview room into a steam room.
- Get Smart. In "Survival of the Fattest", Maxwell Smart loses the Arabian prince he was supposed to be watching. Thinking that a crucial detail might be buried in his unconscious mind that would reveal the kidnapper, Max insists on being handed over to CONTROL's Grill Team, used for sweating information out of enemy agents. Cut to Max with a light shining on his face, being slapped around by two CONTROL agents in shirtsleeves. They're not happy about having to rough up one of their own though.
Max: There must be something...there must be something unusual that I missed! Please, hit me just once more.Control agent: But Max, I can't! My hand is beginning to hurt.
- Doctor Who
- In "Inferno", the Doctor travels to an Alternate History Britain that's been taken over by a fascist dictatorship. He is captured and interrogated by the Brigade Leader, The Brigadier's Evil Counterpart. This consists of the Doctor tied to a chair with a light in his face, being shouted at a lot. It works as well as you'd expect, but it's obvious the Brigade Leader isn't very smart.
- The Chief Caretaker of Paradise Towers tries it on the Doctor, not very effectively. The Doctor learns far more from the conversation than the Chief Caretaker, and by the end of it they've swapped chairs and the Chief Caretaker is the one with the light shining in his eyes.
- Star Trek: The Next Generation. In "Chain of Command" while being tortured by the Cardassians, Captain Picard has four lights shining in his face the whole time. Or are there actually five?
- Subverted in Brooklyn Nine-Nine when Terry, desperate to join his wife as she gives birth, ominously asks for a few minutes alone with the man they're interrogating. Cut to him tearfully imploring the man to give up the names so that he doesn't miss the birth of his child. The man starts crying too and agrees.
- Calvin and Hobbes does this a lot:
Calvin: Lies! Everything Miss Wormwood said about me was a lie! She just doesn't like me! She hates little boys! It's not my fault! I'm not to blame! She told you about the noodles, right? It wasn't me! Nobody saw me! I was framed! I wouldn't do anything like that! I'm innocent, I tell you!
- One incident had Calvin's mother going for a parent-teacher interview with Miss Wormwood, which prompts Calvin to start packing a suitcase to run away. (Calvin does have a perpetually guilty conscience since he misbehaves all the time.) When his mother comes back and tries to talk to him about the conference, she inadvertently Perp Sweats him and he begins panicking as he tries to explain what he thinks Miss Wormwood told her:
- Another time Calvin broke his dad's expensive binoculars, and burst into a hysterical confession at the dinner table when his dad hadn't even found out yet.
- And then there was the incident with sending the family car into a ditch ...
- Used in a couple of story arcs in FoxTrot.
- After punching another kid in the face at school (he was making fun of Peter's girlfriend), Peter comes home expecting his parents to have been contacted and to be chewed out for it. When his mother mentions that the school called her, he bursts into an annoyed monologue about how he screwed up and he knows it, thank you very much... only to have her reveal that they simply called to say someone found his wallet and immediately jump on him for whatever the "fight" was that he mentioned.
- In a similar instance, Peter's mother comes into his room and asks him to "guess what she found under his mattress." He flips out and quickly insists that he only reads those magazines for the articles. Cue her explaining that she found his baseball mitt (he put it under his mattress to break it in) and demanding to know what magazines while Peter begins sweating profusely.
- In Ghost Trick, the backstory of the primary antagonist results from one of these going very badly wrong. An innocent man at the time, he'd been brought in as the main suspect for a crime, and the rookie detective went too far in implying what would happen to him if he didn't co-operate. Scared out of his mind and beyond rational thought, he took the detective's gun and fled the police station, forcing the cops to pursue him to a certain park...
- Implied to be going on if you put a student in detention in Black Closet - a successful detention breaks the suspect's will so that they not only confess their crimes, but thank you for your mercy.
- In The Darkside Detective, McQueen has to improvise an interrogation room at the mall because he can't leave to take the suspect back to the precinct house. Fortunately, the electronics store sells a desk lamp perfect for shining in a perp's face.
- Parodied in 8-Bit Theater with this exchange:
Red Mage: Did you take Matoya's crystal?Bikke: No!Red Mage: No? Or... yes?Bikke: Er... But I... And you... Uh... Damn ye and ye black ops mind games. Yes I stole it! And I'd steal it again given half the chance!
- On Jimmy Two-Shoes, Jimmy attempts to do this to Beezy. Being Jimmy, he doesn't do it very well. Being Beezy, it's effective anyway.
- Referenced in My Little Pony: Friendship Is Magic of all series, where Pinkie Pie uses this to "interrogate" Spike in "Party of One".
- Done to Chuck the Evil Sandwich Making Guy in one episode of WordGirl.
- Mr. Bogus does this to Mole in the third act of the episode "Bogus Private Eye", when interrogating him about the theft of Mr. Anybody's watch.
- In the second episode of Star vs. the Forces of Evil, the goons from St. Olga's Reform School for Wayward Princesses do this to Marco to make him detail where Pony Head is. When this fails at first, they proceed to flicker the spotlight, which prompts him to say:
Marco: STO-HA-HA-HOOOP! That is really annoying!
- Spongebob Squarepants: In "Money Talks", Mr. Krabs shines a desk lamp on a dollar bill to get it to "talk".
- The Loud House: In "Sleuth or Consequences", Lincoln and Lucy shine a flashlight their sisters to get information on who clogged up the toilet.
- Kaeloo: Mr. Cat does this to Quack Quack the duck while trying to get him to confess to a crime he obviously didn't commit. In order to be more cruel, he turns up the lights so much that they actually burn Quack Quack, and then he decides to slam him on the head with a book each time he claims to not be guilty.
- Justice League Action. Superman volunteers to play Bad Cop but is completely hopeless at it, including apologising when he shines the light in Deadshot's face.
Superman: Let's put a little light on the subject... (shines light in Deadshot's face, who winces) Sorry! Too bright? (off Batman's look) I mean, uh...that's nothing compared to my Heat Vision, which will really do some serious damage! So...talk!
- The Hair Bear Bunch put the interrogation light on new cavemate Rare Bear in "Rare Bear Bungle", thinking he's either a mole planted by Peevly or a human spy in a bear suit. (In the comic book adaptation it's Botch in a bear suit.)
- Scooby-Doo: In "Watt a Shocking Ghost," Shaggy, Velma and Scooby put the lights of flashlights on a parrot in an effort to get clues about the 10,000 volt ghost. (Scooby even goes as far as impersonating Lt. Columbo.)