Playing cupid

Especially for Valentine’s Day, Game Theory expert Dr Nicos Georgiou looks into the mathematics of dating.

In the 2001 biopic A Beautiful Mind mathematician John Nash (played by Russell Crowe) devises a dating strategy for his friends.

Although they all fancy “the blonde” in a group of women, he points out that none of them will get her because they’ll end up blocking each other. And if they then turn to her friends, they’ll be rejected because no one likes to be second best.

So the solution is for his friends to approach the blonde’s friends first. Known as Nash’s Equilibrium, it illustrates that the best result comes from everyone in the group doing what’s best for him/herself and the group.

Nash’s Equilibrium is a central application of game theory, which uses mathematical modelling to understand the decisions individuals make and how these decisions affect groups.

It’s not unusual for maths to feature in the quest for love.Traditional approaches to wooing have become such a minefield that it seems reasonable to turn to formulae and algorithms, in the comely shape of dating apps, to select potential partners.

But can a robot really play cupid?

“None of the apps is perfect,” says Dr Nicos Georgiou , a Senior Lecturer in Mathematics at the University of Sussex who can apply his specialism in probability and statistics to understand dating strategies.

“From a statistical perspective, the best strategy for an app like Tinder is to ‘swipe right’, or accept every ‘like’, to give yourself the largest pool of people. However, your chances of success depend on you being more desirable than others, while the most desirable people who have the widest choice often behave really badly.”

The apps that create matches based on similar personality traits are also seriously flawed, says Nicos. “They don’t take human elements into account. You don’t necessarily want to be with someone who has all the traits that you don’t like about yourself.”

Once you’ve made a connection, other aspects of game theory come into play. If it looks like it’s all going well and you then think you’ve been “ghosted” (ignored) by your date, you could become a victim of your own insecurities.

As Nicos explains: “If you’re not feeling confident about yourself, you’ll then judge someone else based on your own experience and make the decision to end the relationship - which could be the worst outcome for both of you.”

Aside from dating apps, another mathematical example, the Acceptance Triangle, depressingly suggests that your chance of finding the person of your dreams (or at least better than average according to the criteria you have set) is less than 50 per cent.

But there is a ray of light offered in Parrondo’s paradox, a complicated theory involving losing strategies that counter intuitively shows how incompatible personalities, or personalities that individually may seem undesirable, can have a good relationship by strengthening each other.

“If people are easily discouraged by data they shouldn’t go on dating apps,” says Nicos. “However, Parrondo’s paradox suggests that nobody should lose hope.”

Nicos is a regular contributor to BBC Radio 4’s Puzzle for Today

This article appears in the February editions of Viva Brighton and Viva Lewes

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By: Jacqui Bealing
Last updated: Friday, 14 February 2020