# Train

Definition

A discrete (state event) variable that is scored when one subject follows (or is followed by) one or more subjects at close distance. Trains can be of two, three or four subjects.

Examples of trains

▪Actor > B. EthoVision returns all instances when the actor (or focal subject) followed subject B. Here, Actor is the focal subject reported in the results table of in the plots of Integrated Visualization. For example, where subject A is the actor, the instances of the train A > B are found. Where subject B is the actor, no results are found since the train B > B makes no sense. Where subject C is the actor, the instances of the train C > B are found, etc.

▪Actor > Any > Any. This is the predefined train when you create a new Train variable. All instances are found where the actor followed two other subjects, no matter who they were. For example, when subject A is the actor, trains like A > B > C, A > C > B, or A > D > B etc. are found. Similarly, where subject B is the actor, trains like B > A > C, B > C > D etc. are found. Statistics are given for all the combinations of “Any” subjects pooled together.

▪B > A. This definition returns all the instances when subject B followed closely subject A.

▪A > Actor > Any. This definition returns all the instances when the focal subject was followed by individual A and followed any other subject.

Calculation

The state Train is active when:

▪The speed of the subjects is higher than the minimum value specified (see below).

▪The distance between the actor’s nose point and another subject’s tail base, or the distance between the actor’s tail base point and another subject’s nose point is less than the maximum value specified (see below).

How to specify Train

1.Open an Analysis profile and in the Dependent Variables panel, under Social, click the Add button next to Train.

2.By default, the variable Train contains a predefined train with three animals: Actor > Any > Any.

▪To define new trains, follow the steps below.

▪If you do not want to have the predefined train in this variable, select that train definition under Settings and click the Delete button.

3.Click the Add button to make a new definition of a train.

The Add Train window opens with the names of the subjects listed on the left.

4.Select the name of the first subject in the train, that is, the one that follows the other subjects. Next, either double-click the name or click the double-arrow button.

As a result, the subject’s name is placed under Train.

5.Repeat the steps above for the second, third etc. subject that must be part of the train definition.

6.When ready, click the Add button.

7.As a Result, the new train definition, in this example Actor > A > C, is added under Settings.

8.Do one of the following:

▪To add more train definitions, repeat the steps above beginning from step 4.

▪If you are ready with the definitions, click the Close button in the Add Train window.

9.Adjust the thresholds if necessary (see below for details).

10.Complete the procedure to add the variable to the Analysis profile. See Calculate statistics: procedure

Notes

▪Maximum distance (nose - tail base). A train is defined only if the distance between subjects, measured between the nose-point of one subject and the tail-base point of another subject, is less than the value specified. This condition must be valid for all the subjects in the train definition.

▪Minimum velocity. A train is defined only if the animals that follow each other are faster than the value specified.

▪Exclude instances shorter than. You can use this setting to filter out instances that are too short to have biological meaning.

▪To delete an existing train definition, select that definition under Settings and click Delete.

▪To delete an element of the train, in the Add Train window click the Delete button.

Click multiple times until the element is deleted from the definition under Train. If necessary, add more elements to complete the train definition.

See also

▪Dependent variables for Live Mouse Tracker