Besides photographs, each user's profile could include any number of personal details including age, height, weight, education, marital status, number of children, and smoking and drinking habits.
The data set includes some 1.1 million interactions between users.
Bruch's team devised a statistical model that maps the "decision rules" people follow during the first two steps.
Bruch and her team divided the rules into two broad categories, "deal breakers" and "deal makers," used to exclude or include people for the next level of contact.
"I expect positive selection to kick in at a later stage of the search," he says.