Knowledge Base

Analysis of Trial Control Data

Trial Control Events

• Makes sub-rule active (for sub-rule references): Marks the time that a reference to a sub-rule triggers the sub-rule. This is the time that one of the Start conditions set in the Reference box becomes true.
• Makes sub-rule inactive (for sub-rule references): Marks the time that the last repeat of a sub-rule planned for a specific Start condition is completed.

Notes:

• For a condition like Is the subject in zone A?, choose Becomes true to consider the moment when the condition is met. Choose Becomes inactive when you want to consider the time that a condition could be met (no matter whether or not the subject is in zone A).
• Becomes active/inactive are especially used when analyzing intervals (see below).

Trial Control States

If you are interested in the time interval between two events — for example, from the Action "cue light on" to the Condition "subject on shelter" being met — use the Trial Control state function in the Analysis profile.

1. In the Experiment Explorer, right-click Analysis Profiles and select New, or click an existing profile.
2. In the Dependent Variables pane, under Trial Control, click Trial Control state or drag it to the middle of the screen, or click the button next to it. The Trial Control State window appears.
3. Next to From, from the Element list select the Trial Control element that makes the criterion for the start of the interval. From the Event list, select the event that marks the start of the interval.
4. Next to To, from the Element list select the Trial Control element that makes the criterion for the end of the interval. From the Event list, select the event that marks the end of the interval. The event that marks the end of the interval may occur multiple times. Therefore, choose which occurrence (from 1st to 9th) should be used. The 1st occurrence is the first occurrence of the event selected under To available after each occurrence of the event selected under From.
5. Select Ignore last interval if incomplete to ignore the interval when the Trial Control event that defines the end of the state is not found. If you do not select this option and the end criterion is not met, EthoVision XT defines an interval up to the end of the track.
6. An interval may occur several times in a trial. If you want to have statistics for each occurrence, select the Calculate statistics per interval option. Next to For consecutive intervals, choose the range of occurrences of the intervals you want to have in the results.

   Example: If the interval from Light On (cue) to Mouse on Shelter (response) occurs 10 times and you want to have the first four occurrences displayed in your table, select 1 to 4. If you want to have all occurrences displayed, select 1 to 10.

   Note: If you do not know exactly how many instances of the state interval the tracks contain, enter a reasonably high number (for example, 50 or 100) to ensure analysis is carried out on all instances.

   Note: If you do not select this option, the multiple occurrences are considered as one interval. Click the Trial Statistics tab and select the statistic you want to analyze. Click the Group Statistics tab and select additional statistics if you want summarized statistics over all trials or the groups of trials defined in your Data Profile. Click Add. The new Trial Control state appears in the list of Selected Dependent Variables.

7. Choose the option you require:
   • To calculate statistics of the selected intervals, from the Analysis menu, select Results and then Statistics & Charts. The analysis window that appears has the tab Trial Statistics for the analysis results per trial and Group Statistics for the statistics and charts from the summarized results over different trials. If you have different filters, data profiles, or analysis profiles, make your selection on the toolbar. Click Calculate.
   • To visualize the intervals, choose Analyze > Results > Plot Integrated Data.

Notes:

• If one or more other instances of Trial Control state are listed under Selected Dependent Variables in the main window, the Trial Control state name is followed by a progressive number (1, 2, 3...). It is advisable to rename the trial control state (right-click the name and select Rename).
• The Element list contains the Trial Control elements defined in all your Trial Control Settings. For each element, the list shows the Name of the corresponding Trial Control box.
• Choose Becomes active instead of Becomes true when you want the interval to be based on a condition from the moment it could have been met, regardless of when it was actually met.
• If you define an interval by choosing the same event under From and To, the instance of the event marking the end of the interval is not used as a starting point for the next occurrence of the interval. For example, given a sequence of four actions of the same type: A1, A2, A3, A4 — selecting a trial control state From A To A results in analyzing the time between A1 and A2, and between A3 and A4.

Trial Control States Based on Conditions

The sample time at which a Trial Control state starts or ends also depends on the statistic used in the condition in the Trial Control rule.

• If you use Current to define the condition (for example, when Current In zone = true), the Trial Control state starts or stops at the expected sample time.

Source: EthoVision XT 18 - THC - Trial and Hardware Control, Noldus Information Technology