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Posted by sanity 21 hours ago

Show HN: Mediator.ai – Using Nash bargaining and LLMs to systematize fairness(mediator.ai)
Eight years ago, my then-fiancée and I decided to get a prenup, so we hired a local mediator. The meetings were useful, but I felt there was no systematic process to produce a final agreement. So I started to think about this problem, and after a bit of research, I discovered the Nash bargaining solution.

Yet if John Nash had solved negotiation in the 1950s, why did it seem like nobody was using it today? The issue was that Nash's solution required that each party to the negotiation provide a "utility function", which could take a set of deal terms and produce a utility number. But even experts have trouble producing such functions for non-trivial negotiations.

A few years passed and LLMs appeared, and about a year ago I realized that while LLMs aren’t good at directly producing utility estimates, they are good at doing comparisons, and this can be used to estimate utilities of draft agreements.

This is the basis for Mediator.ai, which I soft-launched over the weekend. Be interviewed by an LLM to capture your preferences and then invite the other party or parties to do the same. These preferences are then used as the fitness function for a genetic algorithm to find an agreement all parties are likely to agree to.

An article with more technical detail: https://mediator.ai/blog/ai-negotiation-nash-bargaining/

92 points | 34 comments
hawest 4 hours ago|
Super interesting, thank you for sharing!

I have published some research on using LLMs for mediation here: https://arxiv.org/abs/2307.16732 and https://arxiv.org/abs/2410.07053

These papers describe the LLMediator, a platform that uses LLMs to:

a) ensure a discussion maintains a positive tone by flagging and offering reformulated versions of messages that may derail the conversation

b) suggest intervention messages that the mediator can use to intervene in the discussion and guide the parties toward a positive outcome.

Overall, LLMs seem to be very good at these tasks, and even compared favourably to human-written interventions. Very excited about the potential of LLMs to lower the barrier to mediation, as it has a lot of potential to resolve disputes in a positive and collaborative manner.

harvey9 36 minutes ago|
Too many chatbots maintain a relentlessly 'positive tone' anyway, and sometimes a negative situation calls for honestly negative tones.
lookACamel 4 hours ago||
Great idea though I am skeptical it will be adopted in contentious situations without some sort of stick. In amorphous situations where there is just high trust but an aversion to talking things out I could see this kind of tool being used. But in contentious or low trust situations (strangers) I suspect most people do not want fairness, they want to be ahead. A fair agreement will, paradoxically, disappoint everyone since every party feels the lack of clear advantage.
webrot 2 hours ago||
I think this is very useful. I wonder if you have people that actually used in difficult situations? maybe family separations or challenging stuff like that, where I see a lot of potential but also resistance.

This said, I think the challenging part for the users is clearly setting the utility function. I agree LLMs can help there, but I have few concerns wrt that.

vintermann 5 hours ago||
This doesn't seem to have any notion of power? Coming up with a fair agreement between people who have equal power over the thing they care equally about, isn't that hard.

But when one side is indifferent to something the other side cares deeply about, yet has veto power to spoil it, a Nash agreement isn't going to be "fair" in the usual sense of the word.

sgsjchs 59 minutes ago||
You have it backwards.

This formal game-theoretic notion of fairness acknowledges that power disparity exists and that having less power than your counterparty allows them to inflict greater disutility on you without you being able to inflict disutility on them in turn to discourage this.

On the other hand, fairness "in the usual sense", pretends power disparity doesn't exist and that, say, an armed robber is not allowed to take your stuff when you have nothing to defend yourself with. Which in reality only works as long there is a powerful third party (the state) that will inflict disutility on the robber for it.

maxaw 4 hours ago||
In reality people never have equal power over anything (what would that look like, physically?) so something like nash bargaining is an attempt to get closer to a notion of fair given this inequality
vintermann 4 hours ago||
I don't think the difficulty of equal power is a good excuse to pretend power doesn't exist.

One way we solve it in the real world is that the negotiators also have power - including, possibly, the power to force the party most OK with the status quo to come to the negotiating table, and reject exploitative proposals.

That isn't foolproof either, of course. But it beats rhetoric trying to convince the weaker party to submit.

maxaw 47 minutes ago||
I didn’t say it doesn’t exist, rather that it’s already taken into account. I’m also not sure what you are proposing- if mediation is required, and someone has more power than someone else, why would they voluntarily engage with a mediator who will reduce that power? Or if they are forced to use this mediator (eg by the state) then this means they never had the power in the first place
aroido-bigcat 5 hours ago||
Feels like the tricky part here isn’t computing a “fair” outcome, but defining what fairness even means in the first place.

Once you formalize preferences into something comparable, you’re already making a lot of assumptions about how people value outcomes.

alex1sa 4 hours ago|
[dead]
maxaw 4 hours ago||
This is so cool. Even small disputes like roommate arrangements can feel very emotionally impactful at the time and it would be wonderful to have a tool for these moments
ttul 6 hours ago||
Fabulous idea. LLM-assisted mediation is brilliant because it has the potential to bring the benefits of mediation to the masses. The addressable market is all of humanity. Even if all you did was focus this app on co-parenting arguments, you could help millions of people every day.
dhruv3006 5 hours ago||
John Nash's ideas are still relevant today - highlights how great he was - I liked how you used a genetic algorithm here!
danieldifficult 6 hours ago||
Brilliant! Love seeing this space start to wake up.

Last year I built https://andshake.app to prevent the need for conflict resolution… by getting things clear up front.

I agree that AI has much to offer in low-stakes agreements to help people move forward in cooperation.

aspect0545 4 hours ago|
Looks interesting. But where’s the privacy policy or at least information what happens with all the sensitive stuff you enter there. Because let’s be honest, a lot of the stuff that is awkward to talk about is somewhat private.
zachvandorp 7 hours ago|
Its an interesting idea. I've seen a few of these but not with ol' John's spin on it.

Do you want the first link "How it Works" to really be just the # of front page? it makes it feel like it's broken if someone clicks it. Also your blog about Nash Bargaining is almost more of a "How it Works" page than the How it Works page is.

I feel like your landing page very quickly told me what your website does which is great. If the Nash Bargaining is the "wedge" to separate you from the pack, I'd try explain how that differentiates this over the others as quickly as possible. I know that's easier said than done. Good luck!

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