String Input Problem; Randomization Question

Hi everyone,
I’ve read through a bunch of the other threads and it doesn’t seem that anybody has my particular problem(s).

  First, I have an experiment where I want subjects to write in the names of colors they have been shown on the keyboard after they appear. In each trial, there is a fixation point for a second, the color appears, there is an ISI, and then a string edit box is supposed to appear. The participant is supposed to fill out the box, click "Enter", and then move on to the next trial. I can't get this to work. If I make the event end "after any response from the participant", then one of two things can happen. If I have the string edit field appear for all events, it freezes when I try to type anything in. If I have the field appear only when an event has a designated correct response, then either (a) the field never appears at all, or (b) it freezes when it does appear and I try to type anything in it. (Whether (a) or (b) happens depends on whether any correct response has been defined, but see below.) Now, I really don't want to define the "correct" answers, because I want participants to type anything in (up to a certain length). But, even if I do designate the "correct" answers, and tell the event to end only after a correct answer, the field still freezes.
  Really, all I want is a string edit field that disappears after you type something in and press enter.

  My second problem is about randomization. Each stimulus is a color patch that appears for a certain period of time. The stimuli are defined by the hue of the patch, the size of the patch, and the duration that it remains on screen. I have made a separate event for each hue-size pair. Is there any way that I could have each hue-size-duration triple appear exactly one time each, in random order, without making an individual trial for each triple? I could actually do that, but it would take me a few hours, since there are so many hue-size-duration triples. I haven't been able to get the variable ISI duration thing to work, and I suspect that might be the key. Any suggestions?

Thanks in advance!

randomization idea

Is a hue-size item actually an image file? If so, if you made one prototype trial for each duration that uses a stimulus list containing all of the hue-size items, then that might be close to what you need, once you randomize the trials.

Let’s say you have four durations, and five hue-size items. You make four trials, each containing an event that uses a stimulus list containing all five of the hue-size filenames. You set up a block containing five of each one of these trials, or a total of 20 trials. Next, you can expand the stimulus lists so that in effect, each trial becomes a free-standing triple. If you randomize the trials in that block, you’ll have a random presentation of the 20 triples.

I think you need to expand the stimulus lists, or otherwise each duration-trial will read the stimulus list in the same order (11112222…), which isn’t what you want.

I haven’t played with string input, so I have nothing to suggest about that.

Greg Shenaut

If you are using string input and single-key input, both input methods MUST be configured to only be enabled if a correct response has been defined. You don’t have to configure the event to only end on a correct response, but you do have to define a correct response.

If both input devices are enabled, then there’s a 50% chance that a keypress will be interpreted by single key input, and 50% for string input. As a result, things don’t generally happen the way you want.

Thank you both very much! Greg: your idea worked perfectly. Hank: I don’t think that’s the issue, but I’ve fixed it by changing the input to single-key strokes. The output from SuperLab doesn’t look quite the way I’d like it to (each key is in a separate cell), but that’s perfectly manageable.

Thanks again!