The programme hoped to demonstrate how crowds, when they think they're anonymous, behave much worse than they would if they were individualised. The set up was a fake gameshow. The audience believed they were there as audience, rather than the subject of the experiment. The gameshow featured hidden cameras watching a ordinary member of the public in a bar. All the other characters were either friends in on the set up or actors.
The audience were offered 2 scenarios: one positive (=A), one negative (=B), and asked to vote on which scenario they wanted to happen next. Invariably the majority of the audience chose the negative option, which was then carried out, all watched by hidden cameras. This, according to Derren, showed mob behaviour in action. However, as a writer I disagree. These were the options.
1st Choice - X in bar:
A: have a pretty girl flirt with X
B: have girl accuse X of touching her bottom and call over her angry boyfriend.
2nd Choice - still in bar:
A: Angry boyfriend apologises and buys X a drink
B: Barman accuses X of not paying his bill and demanding money, or he'll be thrown out.
3rd Choice - X leaves bar and goes to a shop.
A: He's the shop's 5,000th customer and gets bag of goodies
B: He's accused of shoplifting; the police are called.
4th Choice - Police arrive, look at CCTV footage (offstage):
A: X is let off, there's nothing on the film
B: The film points to X's guilt - he's arrested.
5th Choice - phone call from work colleague, she tells him:
A: She's won a TV, and is going to give it to him
B: He's going to be made redundant on Monday
6th Choice - dropped off back at home by police
A: He gets £10,000 for taking part
B: He's kidnapped by masked thugs.
All the A choices were Closed choices. The story either ended at that point, or would continue in a predictable manner. All the B choices were Open choices, in that you didn't know where the story would go or that it was adding more drama not closure. All the B choices also involved conflict.
So, instead of demonstrating mob rule and a natural propensity to cruelty, I would argue that the programme showed people want excitement and conflict and on-going situations. Good story telling, in other words.