How was your day yesterday? It’s not a hard question, but chances are you’re going to give the wrong answer.

That’s the thinking behind a new app, Expereal, which aims to measure and track our daily emotions. The app, available on iOS, was released November 2012.

What’s the Deal?

Expereal’s creator Jonathan Cohen was inspired by the work of economist Daniel Kahneman, who argues for the difference between a “remembering” and an “experiencing” self. Basically the idea is that the way we feel in the moment — say, while eating lunch or while taking a difficult test — can be a lot different from the way we remember feeling afterward.

For a program that could change our understanding of the human brain, the app is ridiculously simple. Users sign up through Facebook (you can’t sign up without a Facebook account) and are immediately presented with a colorful wheel and the numbers one through 10 (the numbers indicate how they’re feeling). It’s also possible for users to include little notes about where they are, what they’re doing, and who’s with them. Throughout the day, the app sends (optional) push notifications asking “How are you feeling?” prompting users to repeat the whole process.

The coolest part about the app is the way it collects information. Hit the “visualize” button and up pops a graph showing three sets of data. The blue line shows how the individual user’s mood has fluctuated over the past week. (There’s also an option to see how your mood has changed over the past month.) The gray line shows the average emotions of all Expereal users. Another line shows the average emotions of all the user’s Facebook friends who use Expereal. (Note: Data is anonymous, so you won’t know which of your Facebook friends uses Expereal or how they’re feeling unless they choose to make their information public.)

Is It Legit?

Hard to say. Cohen’s definitely onto something, but his ideas about what the app should accomplish are still pretty vague. “Ultimately we want it to be about self-knowledge, self-understanding, leading to self-improvement,” he says in a video message to potential users.

Still, this app is a handy way to test out Kahneman’s, and other experts’, ideas about human memory. Kahneman’s work suggests there are a number of cognitive biases that skew our memories of different experiences. For one thing, we tend to hang onto negative experiences, meaning if the whole day goes according to plan except for the moment when we spill soda on the boss’s lap, we’ll probably remember the day as pretty badMemories of yesterday’s emotions: does the valence of experience affect the memory-experience gap? Miron-Shatz, T., Stone, A., Kahneman, D. Center for Health and Well-Being, Princeton University, Princeton, NJ. Emotion 2009;9(6):885-91.. The end of an experience is also important: Studies have shown that if a painful medical examination is followed by a few minutes of less pain, we’ll remember the whole experience as less aversive than if the exam just ended after the painful partDeterminants of the remembered utility of aversive sounds. Schreiber, C.A., Kahneman, D. Department of Psychology, University of California, Berkeley. Journal of Experimental Psychology 2000;129(1):27-42.Memories of colonoscopy: a randomized trial. Redelmeier, D.A., Katz, J., Kahneman, D. Department of Medicine, University of Toronto, Toronto, Ontario, Canada. Pain 2003;104(1-2):187-94.. Another, controversial, idea is the “peak-end” phenomenon, which happens when we remember our feelings during the entire event as the average of the emotional peak and the end of the experienceEvaluating multiepisode events: boundary conditions for the peak-end rule. Miron-Shatz, T. Woodrow Wilson School for Public and International Affairs, Princeton University, Princeton, NJ. Emotion 2009;9(2):206-13..

Cohen’s app is also one of the first self-quantifiers to measure anything psychology-related. With the abundance of apps on the market that measure how much fuel we burn, how many calories we consume, and how many times we pee, it’s nice to see that someone thinks our thoughts and feelings are just as important.

Would you use an app that tracks your emotions throughout the day? Let us know in the comments below or tweet the author at @ShanaDLebowitz.