How to use MatLab to understand the number of contacts or interactions

[Gema Jiménez]

Hi! 

I new to MatLab and I'm having trouble understanding the output given by Id Tracker. 

I do know I have to use the trajectories.mat file and upload it to MatLab. 

I understand that we are given a matrix where the columns are the individuals, the rows are the frames and... are the numbers inside the coordinates (x, y)? 

Could please someone explain me how could I use the data to see the number of times the mice "touch" each other? And for how long? 

Thank you so much in advance!