Keeping track of simultaneously-presented stimuli

SuperLab SuperLab 4 Support
1

Hi,

I’m conducting an experiment in which I present subjects with two image stimuli simultaneously. The first stimulus is presented using the ‘move on immediately after this event…’ option, with the ‘record and save responses’ option checked on. The second image is presented for 10s, after which both images remain on the screen while subjects key in their input (this last part is coded as a separate trial).

My problem is that because I want to randomly assign these stimuli, I need to keep track of the specific items that are being presented on each trial. The program currently keeps track of the second stimulus in the datafile, but not the first (the ‘move on immediately’ item). Is there something I’m missing here? I’ve tried playing around with a number of response options, and none of them seem to make the program record the item number of the first stimulus.

Any help would be appreciated,

Thanks,

Cody.

2

A workaround is to change the setting on the first stimulus. Instead of having the stimulus move on immediately, have it end on a time limit but make it a very short time limit, e.g. 1 msec. This will make SuperLab write an extra line in the data file, and the response will be “NR” for no response.

3

Great, I’ll give that a shot. Thanks!