blurred image paradigm

I appear to have a challenging problem that I have not been able to solve on my own. I want to do the following:

Present a block of trials in which each trial consists of showing a series of images (the first is a blurred image, the 15th one is much less blurred, and the 30th one is very clear) at a pace of 500 ms per image. I want the participant to respond by doing the following: at the moment an individual believes s/he knows the identity of the individual in the image, I want the participant to press a key and then enter a string (i.e., the identity of the person shown in the image). {Note that it would be fine if the participant just started typing in the identity.} Also, it would be ideal if the participant’s response would end the trial so that the screen would go blank and after some type of input (key or string), the NEXT trial would begin.

Is there a way to fulfill my goal(s)??


I forgot to say that I also need to be able to record (somehow) the number of items in the 30-item series that were viewed prior to the participant’s response.

Thanks …



This should be easily possible with a stimulus list. Set up a block with one trial. In this trial, you will have one picture event, and this picture is pulled from your list. You will set the event to end on either a response (string input) or a time limit.

Where you go from here depends on how strict your 500ms limit is. If you need exactly 500ms between stimuli (e.g. with an fMRI or EEG), you will need to set the event to about 490ms, and set your trials to be presented at 500ms intervals. In either case, you will be better off if you can load all stimulus files prior to starting the experiment (this way SuperLab isn’t taking time between images to load the next one).

If you don’t need trial synchronization, don’t use it. 4.0.2 has a bug in this feature.