Template: Visual Search Paradigm
Visual Search Paradigm

Required Experiment Builder Version: or higher
EyeLink Required: Yes
Type: Concept Example
Difficulty Level: Intermediate

This example illustrates:
  • How to use Custom Class (VisualSearch.py) to set position of target and distractors (see below for more information)
  • How to use Send EyeLink Message node to send Interest Areas messages for better Data Viewer integration

The Visual Search Paradigm consist of 6 trials. On each trial, an array of distractors (Red Circles and Green 'X's) appears and subjects are suppose to search for a target (Green Circle). The target will be present on the first 3 trials and absent on the last 3 trials.

Both examples use a Custom Class (Python) to determine positions of the target and distractors, while target presence/absence and set size are defined in the Data Source. First take a look at VisualSearch_CR2, with a short Custom Class that simply distributes the target / distractor positions. An important note is that for the Display Screen in which you present the stimuli, you'll need to include a resource (Image or Text) for each possible target or distractor. Also note that the order in which objects are added to the Display Screen is important--under the initialize method, you'll see the project grab the handles of these objects:


[0] being the first added to the screen, [1] the second, and so on. (This corresponds to the order they'll appear in the Structure panel.)

VisualSearch_displaySize.ebz expands this a bit. It demonstrates how to write Data Viewer integration messages, so that once the project is opened in Data Viewer, you'll see all of the background images properly loaded, as well as interest areas around each object in the display. (More specific info on these integration messages can be seen in the Data Viewer manual under the EyeLink Data to Viewer Integration section.)

  1. Download the VisualSearch_CR2.ebz or VisualSearch_displaySize.ebz example from this message.
  2. Launch the Experiment Builder application.
  3. Unpack the VisualSearch_CR2.ebz or VisualSearch_displaySize.ebz file to a location on your Experiment Builder PC with "File menu -> Unpack".
  4. Open the project in Experiment Builder.
  5. Deploy the project to a new folder.
  6. Run the VisualSearch_CR2.exe or VisualSearch_displaySize.exe from the deployed directory.

.ebz   VisualSearch_CR2.ebz (Size: 28.97 KB / Downloads: 58)

.ebz   Visualsearch_displaySize.ebz (Size: 1,021.84 KB / Downloads: 31)