For the next two days, the three housemates the group consider the most intelligent will play scientists, while the rest will be lab rats. The scientists must correctly predict how well the rats will do in various amusing experiments.
Photo Gallery - Big Brother 'Lab Rat' task:
Copyright: Channel 5The first challenge involves the rats walking through a human-size hamster wheel, while the second is titled 'Eyes on the Prize' and involves the rats staring at prizes as Big Brother attempts to distract them with a 17ft snake, a Justin Bieber lookalike singing 'Baby' and a burlesque dancer performing a cheeky routine.
The third challenge is called 'Carrot or Stick' and will involve cheerleaders and gunge. The winner of 'Carrot or Stick' will then be pranked as Big Brother gives the other rats earpieces for a pretend hypnotism challenge. The scientists will contact the housemates and tell them to perform certain acts and the test will be to see if the one non-earpieced housemate follows the rest of the group.
Finally, one housemate will sleep in the large task room tonight (June 19) with soothing messages such as "You are a smart, intelligent rat" and "You are a successful rat" being played into the room. Big Brother will test if the uplifting messages help that rat in Wednesday's (June 20) 'Impossible Maze' challenge.
Big Brother continues every night on Channel 5.