"You can get more with a kind word and a two-by-four than with just a kind word."—Marcus Cole, Babylon 5
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.
- Be as Unhelpful as Possible
- Bluffing the Murderer
- Confess to a Lesser Crime
- Don't Answer That
- Enhanced Interrogation Techniques
- Exasperated Perp
- False Roulette
- Gene Hunt Interrogation Technique
- Good Cop, Bad Cop
- High Altitude Interrogation
- Jack Bauer Interrogation Technique
- I Never Said It Was Poison
- Interrogation by Vandalism
- Lying to the Perp
- Rabid Cop
- Rats in a Box
- Twerp Sweating (not actually a subtrope, but related)
- We Have Ways of Making You Talk
Two characters Perp Sweating almost never works on include The Sociopath and people with Aspergers Syndrome, totally different types of person, both on a different level of communication to you. The Sociopath will be two steps ahead of you and retaliate with a Hannibal Lecture. A person with Aspergers will be seven or eight steps behind, 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.
- 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.
- Ninin ga Shinobuden 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.
- L.A. Confidential had such a successful Perp Sweating that the men being held were not only in tears, but actually crapping themselves.
- Dustin Hoffman's character Mumbles is subjected to a deliberately over-the-top example of this in the 1990 film Dick Tracy.
- 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.
- Harvey Dent does this to the man who apparently killed Jim Gordon in The Dark Knight. Harvey abducts him from the ambulance, ties him up in a chair, and threatens to shoot him if a coin flip turns up 'tails' unless he talks. The coin is a two-headed one, so Harvey never really intended to shoot the man. Batman puts a stop to this because a) the perp is a mental patient and thus isn't truly culpable for his deeds and b) Gotham's "White Knight" shouldn't be resorting to such unethical tactics.
- In Muppets Most Wanted, this is done in verse! Unfortunately, given as these are the Muppets, Jean and Sam don't get much info, eventually concluding that the "suspects" are innocent because they're too stupid to have committed the heist.
- The Action Heros Handbook - "How to Interrogate a Suspect" discusses common perp sweating techniques and how to tell if a suspect has something to hide.
- One of Robert A. Heinlein's early (and non-SF) short stories played with the trope - when a suspect who was known to be afraid of the dark was brought in for questioning, they put him in a completely dark room. He cracked quickly.
- Subverted/Inverted/Monkeywrenched in Law and 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's Genre Savvy, 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 a)he's a disappointment to her, and b)he's afraid of the dark. There happens to be a closet down the hall. Awesome ensues. Because apparently Law and Order takes place in a bizarre parallel universe where Torture Always Works. And apparently is legal.
- In Law and Order: Criminal Intent, Goren is very good at this.
- In NCIS Leroy Jethro Gibbs is famous for his skill at this. And when Gibbs can't crack them, sometimes he lets Ziva have a turn.
- 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.
- 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 SPD 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.
- 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. 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".
- Calvin and Hobbes does this a lot:
- 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:
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!
- 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 ...
- Also 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 he 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 and demanding to know what magazines while Peter begins sweating profusely.