Empirisoft Support

    Welcome to Empirisoft Support
Results 1 to 4 of 4

Thread: Visual search

  1. #1
    Join Date
    Jun 2008
    Posts
    2

    Visual search

    Hi,

    is it possible (and not too complicated) to program visual search experiments with direct rt? This entails, inter alias, the presentation of multiple stimuli at multiple locations, with a random assignment of locations to stimuli. I went through the examples, which however, were not conclusive in this respect.

    Thanks,
    Gernot

  2. #2
    Join Date
    Nov 2005
    Posts
    3,328
    Would need a little more detail, but it sounds like something DirectRT could usually handle. Would depend on your randomization plans/constraints. e.g., with, without replacement. Also, what do you mean by inter alias?

  3. #3
    Join Date
    Jun 2008
    Posts
    2

    Visual Search Experiments

    In a visual search experiment, there are target present and target absent trials. In target present trials, the target (e.g. a happy face, or the letter H or U) is presented within distractors (e.g., an angry face, or other letters, respectively), and in target absent trials, only distractors are presented. The number of stimuli is varied (e.g., 3, 6, and 9) between trials to estimate search efficiency, which is the time needed to process a distractor. There are many ways to layout the stimulus display (e.g., matrix or circle), but very often there are more positions on the screen than stimuli, that is, the positions are irregularily filled. The position of the target and the other stimuli may be controlled, but most often they are simply determined by random. Sometimes distractors are all the same (homogeneous), but of course, sometimes distractors are heterogeneous. Drawing without replacement is probably more typical than with replacement

  4. #4
    Join Date
    Nov 2005
    Posts
    3,328
    If randomization without replacement is more common, then you could just create a set of trials with varying location values for the stimuli and then randomize the order of those trials. Would that work for you?

Similar Threads

  1. visual analog scale (VAS)
    By lncs in forum DirectRT Older Versions: How Do I...
    Replies: 11
    Last Post: 09-20-2010, 04:35 PM
  2. Visual Basic .XLA message
    By jarvis24 in forum DirectRT Older Versions: Troubleshooting
    Replies: 1
    Last Post: 01-17-2007, 04:32 PM
  3. Visual Analog Scale (VAS)
    By jarvis24 in forum MediaLab Older Versions: How Do I...
    Replies: 1
    Last Post: 11-09-2006, 03:04 PM
  4. Visual Probe in DirectRT
    By surpass in forum DirectRT Older Versions: How Do I...
    Replies: 1
    Last Post: 10-17-2006, 04:54 PM
  5. Divided Visual Fields
    By Shears in forum DirectRT Older Versions: How Do I...
    Replies: 1
    Last Post: 09-13-2006, 02:31 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •