I have a similar story, but perhaps even stranger.

I work for a startup. We often bring a wooden arcade with us to conferences as a marketing gimmick.

The arcade runs a single side-scrolling video game. You're running from a monster and dodging obstacles. The goal is to survive as long as possible, and your result is measured in meters.

There are always a few competitive guys who spend the entire conference taking turns to play it. And every single time, the same thing happens.

Say the current high score is around 200m. Everybody fails somewhere around that number: 190m, 186m... Maybe someone manages 210m. And the high score moves up at a snail's pace.

Then, a new guy shows up and gets something like 500m on his third try. From their next turn on, everybody easily does 450 or more, even though they were struggling to get past 200 just one turn ago.

What makes it stranger is that the game is dead simple. It's not like the new guy discovered a move that unlocked this capability. And it wasn't a lack of motivation either - they'd all been playing for an hour already. They just started performing better after seeing it was possible. There has to be a name for this phenomenon.

Reminds me of amateur table tennis. There is a strange dynamic where you down regulate your performance unconsciously when the opponent is playing worse and vice versa.

Could be described as some physical form of this effect: https://en.wikipedia.org/wiki/Asch_conformity_experiments

The term would be conformity / normative social influence.

I wonder if it's the same with the sub 2 hour marathon which was broken this year (it certainly was with the 4 minute mile).

Reference-dependent effort ("bunching" around a target) [1] is probably the closest thing. The existing high score was acting as everyone's reference point. Anchoring [2] is the more general cognitive version.

[1] https://www.nber.org/system/files/working_papers/w20343/w203... [2] https://en.wikipedia.org/wiki/Anchoring_effect