# Make contact

Definition

A discrete (state event) variable that is scored when the subject approaches another one to make contact with it.

Calculation

Make contact is scored when the following conditions are met simultaneously:

▪The distance between the focal subject and the other subject shortens (approach event).

▪The speed of the focal subject is higher than that of the approached subject. If the speeds of the two animals involved in the contact are not different enough, Make contact is not computed.

▪The contact event starts some time during the approach event or immediately after the end of the approach event. That is, the video frame immediately before a contact event must be within the timeline of the approach event.

▪The contact event lasts more than three video frames. Instances of contact separated by one video frame are merged together.

An instance of Make contact starts at the start time of approach and ends at the video frame just before the contact event. It does not include the time of contact.

note In Live Mouse Tracker, contact between subjects is detected when the distance between the contours gets below a fixed threshold. Contact is detected during data acquisition and its settings cannot be modified in EthoVision XT.

How to specify Make contact

1.Open an Analysis profile.

2.In the Dependent Variables panel, under Live Mouse Tracker click the Add button next to Make contact.

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

Example

Subject B has made contact with subject C.

See also

▪Dependent variables for Live Mouse Tracker