Nest

Definition

A discrete (state event) variable that is scored when the subject is in contact with two or more subjects. All those subjects do not move.

Note that the variable Nest has nothing to do with nest-building behavior.

Calculation

EthoVision XT considers the events of type Contact stored in the Live Mouse Tracker database, which overlap with the events of type Stopped. That means that Nest includes only instances when the focal subject is in contact with other subjects, like in Group, with the additional condition that none of those subjects moves.

Finally, instances of Nest shorter than two samples are removed and adjacent instances up to three samples apart are joined to form one instance.

Contrary to Group, EthoVision XT does not split the results based on the identity of the subjects forming a Nest.

How to specify Nest

1.Open an Analysis profile and in the Dependent Variables panel, under Live Mouse Tracker, click the Add button next to Nest.

2.Specify the Nest size.

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

4.If you wish to have the results for all nest sizes in one table, repeat the steps above to add more Nest variables, one for each size.

Example

Subject A (red dot), B (light green) and D (dark green) are forming a nest. Subject C (orange dot) walks around and is therefore not part of the nest.

In the Trial Statistics, Frequency is the number of instances of Nest (color bars on the time line as in the figure above) and Cumulative Duration is the sum of the duration of all the instances in the selected trial (or interval).

Applications

You can use Nest to quantify the tendency of subjects to huddle together and form groups. Nest occurs especially in the sleep (light) phase.