Next, Build and then Test Run your experiment. You’ll see that you will be presented with four images/trials.
Run it a second time. What do you notice? You should spot that the images are in the same order. This happens because we haven’t told Experiment Builder to randomise the order of the trials. To fix this, go back to the datasource and at the bottom there is a check box labelled Enable Run-Time Randomisation. Check this box. When you do this, a button nearby will become active – the button labelled Randomisation Setting. Click this button, as shown below.
Clicking this button will bring up various options. Check Randomise on Roll-over: this means that every time you run the experiment, the images will be in a different random order, as shown below.