## News from the world of Maths

Guilt, so some people have suggested, is what makes us nice. When we do someone a favour or choose not to exploit someone vulnerable, we do it because we fear the guilt we'd feel otherwise. A team of neuroscientists, psychologists and economists have this month produced some new results in this area, using a model from psychological game theory.

A talent search has just begun to find competitors to represent the UK in the first ever European Girls' Mathematical Olympiad (EGMO). But why should a girls-only competition be held and what do we hope to achieve?

We came across the excellent Math Encouters Blog through their post Dimensional Analysis and Olympic Rowing, a response to a *New Scientist* article by *Plus* author, John Barrow.

Math Encounters is about those problems we might encounter any day where a little bit of math can really help.

Ah the humble triangle. This simple shape is one of the first we ever learn. But perhaps you didn't realise just how important triangles are...

We like to think of the human brain as special, but as we reported on *Plus* last year, it has quite a lot in common with worm brains and even with high-performance information processing systems. But how does it compare to online social networks? In a recent lecture the psychiatrist Ed Bullmore put this question to the test.

With the day of the referendum on the UK voting system drawing nearer, Tony Crilly uses a toy example to compare the first past the post, AV and Condorcet voting systems, and revisits a famous mathematical theorem which shows that there is nothing obvious about voting.

*Plus*is going to find it. But to know where to start, we need your help: we'd like to know which of the Olympic sports you'd most like to see covered in

*Plus*. So please vote below — you can choose up to three sports. We'll do our best to cover your favourite sports in the run-up to London 2012 and our coverage will also be shared by our Olympic project Maths & sport: Countdown to the games