Very bizarre approach
I’ve been pondering the feasability of the following approach to making a Superlab scenario conditional on subject input. It depends on two things: (1) the logfile must be flushed to disk after each entry is added, and (2) only stimuli that are loaded from files in mid-run can be subject to the conditions.
What you do is have a separate program running in the background while the experiment is going on, monitoring the logfile’s last few lines (or as much of it as needed). Depending on the contents of the logfile, certain specific images, sounds, or videos would be copied from files whose names do not appear in the scenario into files whose names do appear. To illustrate, in one simple scenario there might be only one trial, repeated ad infinitum, that always loaded a picture called “thepic.jpg”, read a response which is written into the logfile, and waited for one second. But after each response was written into the logfile, the background program would rewrite “thepic.jpg” with a new image, depending on the reponses to previous ones; on the next trial, it would be the current new image that would be displayed to the subject.
Yes, it’s kind of fragile in that some kind of interlocking would be necessary to prevent races and other oddities, but I think that in an extreme case, as a lost resort, it could work. If there were an option within Superlab to respect file locking by delaying until the lock was removed (or some other kind of simple synchronization strategy), then it would definitely work.
I’m not suggesting or recommending this, but I simply throw it out as one strange possibility.
By the way, there are some other, probably more interesting possibilities, such as real-time remote monitoring of things like error rate and mean RT, that you could do with a line-buffered logfile and a background program.