For example, if you feel anxious every time you meet your old sorority sister for brunch, this app may suggest that it's a friendship you could do without.
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We're well past our high school years, but sometimes, life can feel like a scene straight out of Mean Girls—you know, a bunch of catty, gossiping girls preying on the unpopular kids. A new app strives to help you eliminate those types of people from your social circle.

Pplkpr (pronounced “People Keeper”), available for iPhone (free,, tracks your physical response to certain people you interact with using a Bluetooth heart rate monitor. Whenever you have a spike in heart rate, the app asks you to categorize your emotions. Over time, the app gets smarter, and points out patterns. For example, if you feel anxious every time you meet your old sorority sister for brunch, then Pplkpr may suggest that it's a friendship you could do without. Likewise, if the app notices that you feel calm whenever you visit your mom, it may suggest that you schedule more time to spend with her.

The creators, Lauren McCarthy and Kyle McDonald, both Carnegie Mellon artists-in-residence, developed Pplkpr partly as an art project, but also as a way to help people use data to improve their lives. “[We are] asking people, do you really want to see a ranked list of your friends, or have an app decide who should be deleted from your life?” McCarthy told

While Pplkpr was designed to work with the Mio wristband (starting at $87 on, it's compatible with any Bluetooth LE device that transmits heart rate in real time, such as the Polar H7 Chest Band ($52, or the Zephyr HxM ($76, It can also be used without heart rate monitor; it just won’t interpret your feeling automatically. But with a couple taps, you can let it know how you really feel when in the presence of a particular person. After a few interactions Pplkpr might identify your “friend” as poisonous—harsh, but true.