Hi there,
I'm getting ready to program MediaLab for an upcoming experiment. I've actually tried a little - but it's not coming out how I'd like so I'm hoping that you can help me.
In our original experiment, we had videotaped participants during a 10 minute interaction. In our upcoming experiment, we'd like raters to look at clips from these videos and rate them on a number of dimensions. Because we don't want to tire out our participants from watching too much - we've split the 10 minute videos into 30 second clips (so there will be 20 of them for each interaction). We'd like participants to receive one random 30 second clip from the first 2.5 minutes, one from the second 2.5 minutes, one from the third 2.5 minutes, and one from the final 2.5 minutes. After each 30 second clip, they'll rate the video. The trick here is that obviously these random clips need to come from
the same 10 minute session.
After that, they would go on to rate another set of 30 second clips from a different interaction. We also would want to make sure that they wouldn't rate an interaction that they've already rated. We have about 40 or so interactions in total - but participants will probably only rate 15 of them or so.
Does this make sense? How would I go about setting this up? I was thinking that each interaction should probably be set up as a separate condition - but can you program medialab so that participants would randomly view 15 out of the 40 interactions? Also, what code would I use to randomize within each interaction?
Thanks!
Robin Freyberg