The fixation construct provides a timed fixation for use in trials. All the fixation properties along with start time, end time and (actual) duration are recorded.
Creating a fixation
Fixations can be added to trials timelines. Click New item, select
Fixation from the type list and select one of the following creation options:
New: create a new fixation.
Copy: copy another fixation from the current study.
Clone (from a different trial): clone an existing fixation from another trial.
Click anywhere along its row (Figure 1) to open the editor.
Figure 1. Open construct editor
In edit mode, the following properties can be set via the timing table:
- Start mode
Fixed: start time will be measured from the beginning of the trials timeline.
Offset from previous item: start time will be measured from the end of the previous item on the trials timeline. If there is no previous item, or the timeout of the previous item is set to
nil(infinite), then start time will be measured from the beginning of the trial.
- Start time (ms): when to initiate construct.
- Duration mode
Fixed: duration will be a fixed time period.
Random: duration will be a random time period bound by minimum and maximum values.
Factor: duration will be a randomly chosen level from the factor selected.
Level: duration will be set to the value of the chosen level.
- Timeout (ms): duration of construct presence.
In edit mode, the following properties can be set via the style table: