Remember when Facebook confessed to toying with our feelings? Well, Netflix have been at it as well, mucking around with their movie streaming service while doing all manner of psychological experiments on us while we scratch our behinds.
Netflix engineers Gopal Krishnan, Steve Urban, Rangarajan Sreenivasan and Vineet Kannan, have been doing their tests on viewers in a bid to see how we react, so they can collect data, crunch some numbers, and look at the way they do things in the future.
Of course, loads of retailers do this as well, so you shouldn't be too worried - save your tinfoil hat for special occasions.
This is A/B testing, which gives different menu options for different users. So, most people will see a show or a film with the artwork that is displayed on promotional posters or the DVD cover. However, others will see alternative artwork.
In their findings, Netflix found that faces showing clear emotional expressions are likely to get more clicks, as are shows and movies that feature the baddie of the story, rather than the hero.
The engineers said: "The general concept behind A/B testing is to create an experiment with a control group and one or more experimental groups (called “cells" within Netflix) which receive alternative treatments."
"Each member belongs exclusively to one cell within a given experiment, with one of the cells always designated the “default cell"."
"This cell represents the control group, which receives the same experience as all Netflix members not in the test."
"As soon as the test is live, we track specific metrics of importance, typically (but not always) streaming hours and retention."
"Once we have enough participants to draw statistically meaningful conclusions, we can get a read on the efficacy of each test cell and hopefully find a winner."
"From the participant's point of view, each member is usually part of several A/B tests at any given time, provided that none of those tests conflict with one another (i.e. two tests which modify the same area of a Netflix App in different ways)."