max# of images per trial and jumping

[mparmley]

Hello,

I am using DirectRT on a trial basis, and am having trouble creating the input file that I would like (and I'm not sure if what I would like is even possible with DirectRT). I have several questions, and I am sending you the input file (emotion5.csv) that I'm working on . My questions below may make more sense after opening my input file.

QUESTION 1: In my sample input file, I show 10 images in one trial. Ideally I would like to show 100 images in one trial, but the program bumps me out when I try to show that many. I tried putting each image as a separate trial, but a black screen would appear before each image. I'd prefer the images to look more like a continuous change (which occurs when I place them in one trial). Is it possible to have 100 images in one trial?

QUESTION 2: My jump command is not working. In the input file, I have indicated that if they hit the spacebar, they will advance to the next image, but if they hit enter, they should jump to questions. When I hit enter, I just see the next image (it does not jump). Can you see in my input file what I might be doing wrong? (For the output file, I am only interested in when they hit "enter", not the "spacebar").

QUESTION 3: In my input file, when they hit enter, I want them to "jump" to a trial where I ask them several questions. I would like the last image they saw to remain, but I can't get it to remain (even when using 0 for the "clear" option under "loc"). Is there a way to keep the image up there while I ask these questions?

QUESTION 4: Rather than jumping, I would like to do an advanced jump/skip combo (which I'm not sure is possible with DirectRT). I would like participants to hit enter when they FIRST think they see something (in the series of 100 images), then ask questions about what they see. For example, if they hit enter at image #10, I would like to ask them questions about image #10. Then I would like participants to go back to image#11, have them continue, and ask them to hit enter when they are SURE what they see. When they hit enter again (let's say at image#30), I'd like to ask another set of questions (possibly the same questions, possibly different ones). After this, I would want the participant to go to the next trial (which would have another 100 images). In other words I don't want the participant to see images 31-100. These two "stopping" points are driven by the participant, not the experimenter. Is this possible to do in DirectRT?

Any information that you have would be greatly appreciated.

Thanks!
mparmley

[Trevor Newell]

Thanks for the questions! Let's see if we can get them answered.
1.) I believe that within the current versions of DirectRT, the limit is made up of 99 images per trial. This would mean that unfortunately 100 images per trial would not be possible.
2.) The following may help:

If you have stimuli following the jump command on the same trial, DirectRT waits until the end of the trial to jump. If you want a jump to be executed mid-trial then assign a negative value to the trial ID. e.g., To break out of a trial immediately and jump to trial 100, you could indicate rt:44<-210,53<-210. Subsequent stimuli on the trial will be ignored.

Also, check out: http://www.empirisoft.com/directrt/help/directrt_jumping.htm
3.) Remember to make sure that the image is on the same trial. The screen will automatically clear at the end of a trial regardless of what you input.
4.) Yes. The experiment would be a bit long, as you would currently need jump sequences for every image; however it would be possible. In the 2010 copy of DRT this will be a much easier function to manage.

[Trevor Newell]

mparmley - You may also want to check out the following link:
http://www.empirisoft.com/support/showthread.php?t=1136