Q: I just came back from the worst Tinder date ever! My date definitely added at least 20 beauty filters to her profile photo, brought a life-size doll to our date, and spent 15 minutes justifying Hitler's existence...I feel so cheated, but tell me, is it my fault for falling for her photo? 

Promise me this--never blame yourself for taking a chance on love! You, a fearless explorer, have left the cozy but parochial world of "conventional dating" in search of new adventures, and it's only natural that a few rotting space debris come flying your way. But the online dating universe is boundless and ever-expanding, so who knows what beautiful stars and planets you'll encounter in your lifetime! Having said this, I should've warned you that phenomena such as "beauty filters," "flattering angles," and "bad lighting" could distort your field of vision and hinder your judgment, so one should always err on the side of caution and add a Skepticism Filter: apply a 50% discount to every profile picture you see!

Q: That's the problem though--I wish there were some warning system, some rating system in the online dating world...sort of like Yelp or Uber! But I feel disgusted at myself for even considering something so dehumanizing. 

Indeed, dating would theoretically be much more efficient if we had reviews for everyone, but we would basically be trading in our humanity and souls for maximum efficiency. Also, given most humans are walking contradictions and attraction is subjective, it's debatable how accurate ratings would be! Hence we find ourselves in an awkward situation economists call information asymmetry--when one party in a transaction has more information compared to another.

To fully understand information asymmetry, let's consider the scenario below:

Jane, a perfectly normal girl, is browsing Tinder at home. Jane sees the following Tinder profile:

Using her perfectly normal deductive reasoning, Jane concludes three things about Brian:
1) Brian bears a striking resemblance to Zayn Malik;
2) Brian is new in town;
3) Brian is somewhat flirtatious given the winky-face emoticon and playful statements.
Thus, Jane assumes Brian is also relatively normal/friendly and swipes right.

However, here are some facts that Brian *conveniently* forgot to disclose:
1) Brian looks nothing like Zayn in real life;
2) Brian has a terrible, incurable case of bad breath;
3) Brian has an estranged mother who left the family to join a traveling circus; 
4) Because of all the above, Brian is extremely insecure around women and overcompensates by always dating six different girls at a time.

In this scenario, information asymmetry hurts the "buyer" and benefits the "seller": Jane overestimates Brian's quality due to the lack of information, while Brian lacks incentive to provide more information (the more he reveals, the more left swipes he would get). This is why information asymmetry often leads to adverse selection--the party with less information is at a disadvantage to the party with more information.

Q: Okay, that's quite depressing...

Actually, it gets even more depressing. Adverse selection can lead to a downward spiral in quality for the entire market!

Let's make a gross generalization and divide the Tinder market into two equally-common types of goods: High-quality dates (H) and Low-quality dates (L). High-quality dates value commitment, good conversation, and meaningful relationships, while low-quality dates are usually either browsing on their toilet or seeking bootycalls. If our dear Jane realizes she can't differentiate between high-quality and low-quality dates due to missing information,  she will assume the following for every person she swipes: