Millisecond Forums

Hi all,

I'm currently writing a script on Inquisit 3.0 in which participants' eye-movements determine task flow. Specifically, where they look determines whether they are correct or not and how fast they look in the correct place determines how many points they receive (which they are shown on screen after every trial).

Initially, we were going to simply use a reaction time (RT) cut-off/categorical approach (e.g. / branch = [if (trial.16.latency < 250) trial.01]; / branch = [if (trial.16.latency < 500) trial.02] etc.) but now we want to try to determine RT and thus feedback continuously (i.e. from 1-4200 ms).

Further, we would like to build into this continuous feedback a cut-off at 1000ms, RTs over which participants receive no points. Finally, some trials will be "low reward" and others "high reward" - the points received in the former will necessarily be lower than in the latter, even when RT is identical.

The calculation will be (1000 - RT) x 0.002 x reward trial type (1 OR 10).

I have never programmed anything like this before so am unsure how to do it (or even whether it can be done on Inquisit!) but have heard that expressions may be the way to go? If so, how exactly might it look in the script?

I appreciate any help and advice any of you can give.

Thanks,
Jay