A sub-trope of Psychic Powers in which they're used by a psychic character, usually but not always a telepath, to detect the presence of other people. The scope and range of this detection can be varied; from sensing the mind of a guard around the corner to Professor X being able to detect the presence of every mutant on the planet. Sometimes the power is tied to the detection of a mind; machines can't be detected by the psychic (crewed vehicles can), and Psychic Static and the Psychic Block Defense can be employed against it. This may or may not lead to being detected because of the defense.
Sometimes, the detection is limited to other psychics only.
Appears in as many media as do the telepaths providing it, though like them, it's generally restricted to Speculative Fiction and Superhero genres. It's especially common in Video Games and Tabletop Games. In film, TV, comics and animated media, use of this power will involve the Pstandard Psychic Pstance and high effort or contest with someone or something blocking your telepathic radar sweep can result in a Psychic Nosebleed. It's also common to see this represented in Film and Television with the searching psychic's eyes overlaid over the sought-after characters hiding place.
Sub-trope of Psychic Powers, closely related to Telepathy. Commonly used by a Sensor Character. May also invoke a touch of Sensor Suspense. Compare Supernatural Sensitivity (for when a Psychic Power is used to detect the use of other powers) and The Force Is Strong with This One, and contrast Spider-Sense, for a much less focused and instinctual version that detects imminent danger. See Killing Intent for a version that anyone can do.
- Dragon Ball: The main cast has the ability, after a certain point, to sense each other's powers.
- Some meisters in Soul Eater can do this, notably Maka and Joe.
- Newtypes in Gundam are able to sense one another, though how effective this is depends on the relative strength of the Newtype in question. Char, a weak Newtype, really only gets sensed when very close by. Scirocco, on the other hand, is sensed by other Newtypes as an overbearing "pressure" while still dozens of kilometers distant.
- One-Ness users in Destroy and Revolution can sense each other and even when the power is being used.
- YuYu Hakusho has this as a common ability.
- Snow White in Magical Girl Raising Project hears the thoughts of anyone under distress, and part of that ability is being able to pinpoint the location of the distressed person, even if they are hidden or invisible.
- The Boys: Member of the super team Payback, Mindroid, can use his telepathy to detect the presence of another person in an area at least the size of a building. He can't precisely define an exact location, only whether or not someone's in the room or not and what their surface thoughts are.
- In an issue of Chuck Dixon's Team 7, a Russian telepath tries to use this to track them through the Cambodian jungle. It doesn't work, due to a "greater power." She gets a Psychic Nosebleed for her trouble.
- All of the telepaths on the X-Men (Professor X, Jean Grey/Phoenix, Cable, Psylocke, etc.) have displayed this from time to time, though usually only when the plot calls for it. Other times, they seem oblivious to people hiding right behind a door. Professor X and Jean Grey can be seen doing this together in X-Men Forever #7 while trying to track Fabian Cortez.
- Martian Manhunter can pinpoint individuals from miles away, though he often needs to dramatically fly into space in order to do so (presumably so he doesn't hear everyone else's thoughts).
- SHIELD employs a "Psi-Ops" division dedicated to this, whose instruments can allow even normal humans to pinpoint locations of their memories. This has backfired before when the target in question is too powerful and the whole division has been wrecked before.
- Rena, a mutant girl from Mampato, can use her Telepathy to sense or pertel the thoughts of other beings (humans and animals alike), as well as whether those thoughts are of good or evil nature.
- Serenity: River's psychic powers let her detect the incoming Reaver ship as it's descending through the atmosphere.
- Star Wars: As per the above quote, Jedi and Sith can sense the presence of other Force users; picking up a single other practitioner even amidst the myriad of minds on the Death Star. They can cloud their presences enough that Vader doesn't know just where Obi-Wan is, but he knows he is there.
- Charles Xavier from the X-Men Film Series, can detect people around himself, amplified greatly with Cerebro to find almost anyone in the world. In X2: X-Men United he uses it to allow him to track even a mutant who can teleport and it's further revealed that he can use it to sense the location of every mutant or every human on the planet. Concentrating hard enough will give them all a really serious Psychic Nosebleed... followed by death.
- Star Trek: Nemesis has Deanna Troi (even though she's not a full telepath) use her psychic connection to the Viceroy to not only pinpoint the location of the cloaked Scimitar but also specifically target its bridge. The Viceroy realizes what's happening too late to stop it.
- This is only possible because Shinzon (with the help of the Viceroy) previously Mind Raped her while she was having sex with Riker.
- Dracula: This goes both ways with the link between Mina and the Count. He can use it to spy on and know the movements of the heroes, but they can do likewise if they place Mina into a hypnotic trance; so she can sense the Count and his surroundings and roughly how far away he is.
- Oddly, Futuretrack Five's psycho-radar is not powered by a telepath. It's wholly mechanical, but it still works by detecting the presence of thoughts. Paramils are generally scanning for extremes of rage or despair, and particularly home in on the suicidal. It's demonstrated that it can be played with; a favourite pastime of Est children is thinking 'angry thoughts' when a psycopter flies over and then immediately thinking really bland thoughts, just to annoy the Paramils.
- In The Sharing Knife, a lot. Groundsense can detect any life.
- Sholan Alliance: Most of the main cast, who're almost all telepaths or some stripe, have used their telepathy to detect the presence of others at some point during the series.
- Command Performance, a 1952 short story by Walter M. Miller, Jnr., featured a young woman discovering she was a telepath and also that there was at least one other telepath out there; when she psychically sensed him in the street near her back garden. He'd already sensed her and had come to investigate.
- In the Necroscope novels people who have this "Talent" are called spotters, and are rarer even than regular Talents.
- Seekers in Mistborn: The Original Trilogy can hear "pulses" given off by people using Allomancy. The pulses can tell you what metal is being used, who's using it, and even more details if you're good.
- Saleem of Midnights Children can intuitively sense the other midnight children with his Telepathy.
- In Isaac Asimov's Foundation series the Second Foundationers and Gaians, having mental powers, can detect the presence of intelligent beings from interplanetary distances. In Foundation and Earth Bliss can tell the difference between humans, other life such as animals, and even robots.
- In Chakona Space, Chakats are capable of this and have used it several times.
- Angel: In early seasons the evil law firm Wolfram & Hart uses psychics specifically to scan if a vampire has entered their building.
- Blake's 7: Cally, the Auron telepath in the Liberator crew can detect the presence of other minds. It's how she sneaks up on Blake in an early episode.
- Firefly: River's psychic powers let her detect the presence of Reavers aboard a hulk drifting past Serenity and also pick up on the proximity of the blue-handed Alliance agents. It also allowed her to blind-fire a pistol with deadly accuracy.
- Heroes: Matt Parkman can detect people he can't see by hearing their thoughts. In the first episode we meet him in, he uses this to find a little girl who's hiding from a murderer.
- Red Dwarf: During the episode "Quarantine," both Lanstrom and Rimmer, under the effects of the Holovirus, are able to home in on the location of the rest of the crew by sensing their thoughts.
"Unfortunately she has already found you! Twinkle, twinkle, little eye, now it's time for you to die!"— Dr. Hildegard Lanstrom, Red Dwarf "Quarantine."
- Highlander: Immortals can sense when another Immortal is around.
- Doctor Who: Time Lords are capable of sensing each other as said in "Utopia/Last of the Time lords". Since Time Lords periodically change their appearance, then it would make sense for them to evolve a way to recognize each other. However, it only seems to work when the Time Lord is actively paying attention.
- The Detect power could be defined as detecting life in general, or specific kinds of life in particular (minds, aliens, humans or whatever).
- The Mind Scan ability could be used to detect life in an area, though it was normally used to find specific creatures.
- d20 Modern: Telepaths have the psionic ability Detect Thoughts. The longer the telepath concentrates, the greater the area he can scan for other minds and the clearer the number of minds is. This power can be blocked by a sufficiently thick inorganic barrier.
- Dungeons & Dragons.
- Early editions had the Detect Life cleric spell, which could detect living creatures at a distance, and even through solid non-metal barriers.
- 2nd Edition introduced the psionic ability Life Detection, which allowed the user to detect the presence of living, thinking creatures within a limited area.
- Edition 3.5 had the Mindsight feat, which allowed telepathic characters to passively detect any intelligent creature in range of their telepathy. The detect thoughts spell can be used both for this purpose and for mind-reading.
- Space Hulk: 1st Edition had a power, Scan in the game's Temporal deck, which allowed Librarians to identify Genestealer blips. This was later adapted into spin-off Space Crusade and its successor Advanced Space Crusade via articles in White Dwarf.
- West End Games Star Wars d6 gave Force users two powers to use for this trope Life Sense and Life Web. The former allowed them to sense the presence of a specific person and the latter allowed them to search for the presence of specific species. An issue of Planet Hoppers had Luke Skywalker visiting a desert world that has had more rain since his last visit, and noticing that it 'feels' different.
"There are many signs of increase in small animal life: birds, reptilians, and a multitude of insects that sing anxiously through the Force at the lumbering invader from offworld."
- Traveller. The Telepathy psionic ability allowed the user to perform Life Detection. This involved detecting the minds of creatures in the area, including the number and type of minds present (animal, human, alien). It could be set to ignore unimportant animals and bacteria.
- Vampire: The Masquerade: High-level Auspex powers Omniscience (level 8) and Master Of The Dom (level 9) allowed a vampire to, respectively, detect the personalities and identities of individuals within an immediate radius (larger area based on more successes when rolling) and to detect the presence and activity of most people and animals in a regional area.
- Warhammer 40,000 has this as a common power of psykers. This is particularly useful for battlefield psykers, where this ability is ideal for detecting enemy troop movements or spotting ambushes that are otherwise perfectly camouflaged to conventional perception. This is used on space craft as well, where "going cold" is no proof against psychic detection. The measured advice of a few psykers can have a drastic effect on the deployment and success of an entire military campaign.
- This is also used in a broader sense when the Imperium is planning for the long term for a particular region of space, more or less officially called "strategic prognostication". Occasionally, divination tells of a major or ongoing threat that will come to the area, and the Imperium will set up a permanent military presence to watch over the region. Knowing the luck of the Imperium in such matters, it's likely that this has been met with mixed results.
- Seekers in the Mistborn Adventure Game can hear "pulses" given off by people using Allomancy. The pulses can tell you what metal is being used, who's using it, and even more details if you have a high enough Bronze rating and roll well.
- In Eclipse Phase Ego Sense is used to detect other sentient biomorphs, while Omni Awareness points out any living creature that is observing the async. The Scramble sleight and Psi Chameleon general trait are designed to defeat those sleights.
- Command & Conquer: Red Alert has the Psychic Sensor which allows the detection of enemy units outside of Line of Sight and the prediction of their movements. Also the Psychic Radar which psychically revealed sections of the battlefield.
- In NetHack, telepathic characters can see the position of monsters even when physically blinded.
- In Sins of a Solar Empire, the Advent research tree provides players with Forewarning and Acute Premonitions; allowing Advent telepaths to detect hostile fleets bound for the player's territory from increasing numbers of hyperspace jumps distance. The other factions have technological equivalents called PSIDARs.
- Star Trek Online: Telepaths allow for the detection of cloaked vessels and units.
- In many StarCraft Expanded Universe novels, psychics can sometimes detect other psychics. Weak psychic detective Malcolm Kelerchian's only psychic power is detecting other psychics. Nova can detect psychics at great range, even when cloaked, but frequently fails to detect spectres. Head spectre Gabriel Tosh is very difficult to detect using this method.
- The Slugs in FTL: Faster Than Light have telepathic powers with which they can detect lifeforms even without functioning sensors. They evolved these powers being native to ocean planets drifting through nebulae, where they proved more useful than sight.
- In Project 0, modding typically looks like this.