Ultimate Simon


Screenshot for Ultimate Simon

The ultimatum game is an economic decision making game in which people (responders) accept or reject fair and unfair offers from other people (proposers). The Simon task is a type of response conflict task in which people find it harder to act to one side if the stimulus happens to be on the other side (say respond right to something happening on the left). What could possibly relate economic bargaining and cognitive control?


I don’t know.

Well, to be fair, similar mechanisms have been proposed (inhibition), involving similar neural substrates (mainly the anterior cingulate cortex). There is also a somewhat intriguing overlap in the fields in terms of authors. So perhaps there’s something to this.


However, when I programmed this, I had something else in mind. People find it hard to accept unfair offers – the main Ultimatum Game finding – but a binary response gives pretty poor confidence because of the inherent statistical properties of the value. Reaction times are much better! Plus, we could even get data even if people accept something. So what if we rearrange the Ultimatum Game as if it were a conflict task?

The normal finding is that people often fail to accept unfair offers. Let’s say they ‘ultimately’ (sorry) accept a fair offer even if they find it hard to do so? We can expect then that they will take a bit longer, maybe? So I took this idea and ran with it: the stronger the attraction to an economic stimulus, the harder it will be to not respond towards it. Ergo, we should expect a Simon effect if an economically attractive stimulus is presented on the side of the screen that is opposed to a reject decision. Does it? I don’t know, because I couldn’t get anyone to continue this (3-way interaction) line of thinking.

Full source code as E-Prime 2 file (works after upgrading to EP3). 

Leave a Reply

Your email address will not be published. Required fields are marked *