Opinion: How to interrogate a terrorist using diabetic biscuits

Is it more effective to force people to do things, or to charm them?

The surprising answer that’s tucked into the US Senate’s recent investigation into terrorist interrogation, is that, even with hardened Al-Qaeda terrorists, charm is usually more effective.

As Time’s write up notes:

The most successful interrogation of an Al-Qaeda operative by U.S. officials required no sleep deprivation, no slapping or “walling” and no waterboarding. All it took to soften up Abu Jandal, who had been closer to Osama bin Laden than any other terrorist ever captured, was a handful of sugar-free cookies.

Of course it took a lot more than this – but the key point to emerge from interrogators was that persuasion was far more effective at getting useful information out of terrorists. And when interrogators started using violence, they got less information. Torture isn’t just immoral, it’s ineffective too.

Why is this?

Well Robert Cialdini[1], one of the world’s leading behaviour change scientists, has written a fascinating guide to why persuasion worked in terrorist interrogations. The key points include the use of Liking, Commitment and Reciprocity, ideas which are rarely discussed in public policy:

  • Likeability makes people more likely to co-operate. Biscuits for Abu Jandal were the first step in establishing that the American interrogators were human beings.
  • Commitment draws on the idea that once people have committed themselves to a particular view of the world, they try to act consistently with it. So when Abu Jandal was shown evidence of Muslim deaths in the 9/11 attacks, his desire to be consistent with his existing view that Yemeni Muslims should not kill each other, led him to condemn the 9/11 terrorists. Once he had condemned the terrorists, it was consistent of him to help capture them.
  • Reciprocity – by making the first positive move, by giving diabetic biscuits unprompted, the interrogators prompted Abu Jindal to reciprocate by starting to talk. Reciprocation worked the opposite way for another terrorist, Abu Zubaydah, who stopped co-operating when CIA-hired contractors tortured him.

It’s worth a read in full, because of the implications for public policy (though as Robert Cialdini notes, interrogators lying is something we shouldn’t copy). Almost every kneejerk public policy response to difficult problems is to pass a law to force people to do things, at the cost of fines, prison or other sanctions.

What if we saw public policy challenges in a different light, and routinely used persuasion to solve them?

Here’s one other example from public policy that shows this can work.  In Texas a campaign cut littering by 75% in 5 years by using appeals to Texan patriotism (i.e. consistency with your identity) rather than threats of fines. Men who were perfectly happy to ignore a ‘don’t litter’ sign, stopped doing it when Texan celebrities like Willie Nelson told them it was unmanly.

I’m collecting examples of councils, governments and NGOs using behaviour change science to influence people positively. What examples have you seen?

[1] Declaration of interest: I am acknowledged in Robert Cialdini’s latest book, ‘The Small Big’.

* Rob Blackie is a candidate for the 2024 London Assembly elections. A former aid worker, he advises charities and corporates on strategy.

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This entry was posted in Op-eds.


  • David Faggiani 12th Jan '15 - 2:16pm

    I like the idea of interrogating terrorists (and other criminals) by exposing logical absurdities/implications of their beliefs. I would suggest this technique be coupled with a 9am start – it worked very well for our Moral Philosophy tutor at University. After an unrelenting term of those seminars, we would have told him literally anything, and we didn’t even get biscuits.

  • Peter Watson 12th Jan '15 - 3:27pm

    A few years ago I thought that sugar-free sweets for diabetics were a great way to “cheat” when trying the Atkins diet.
    The resulting strong laxative effect and noises that I thought only existed as sound effects in american gross-out movies make me feel sorry for these terrorists.

  • Diabetic biscuits are full of carbohydrates and like other so called “diabetic” food should be avoided like the plague.
    IRA operatives would often sing like a canary once caught.

  • Dominic Curran 13th Jan '15 - 12:42pm

    I’ve watched the LibDems in coalition do lots of things that have appalled me so much that I’m probably going to vote Green in May. Does that count, Rob?

  • When I was a small boy and all TV was black and white there was an excellent TV series call ‘Spycatcher’ based on the real life story of Oreste Pinto.

    The unspoken logic of every episode was that ‘our side’ was not only morally superior to ‘the enemy’ by not resorting to torture or the threat of torture but also that our side was therefore more effective at getting the information required.

    A similar theme runs through some of the spy fiction that was knife sent in the 1960s. George Smiley would have happily shared a cup of tea and a biscuit and engaged in quiet conversation with his suspect. He would have suggested that military intelligence was best when it employed a modicum of intelligence.

    Rob Blackie asks for examples of behaviour change; my guess is that he is already fully aware of the significant reduction in adult smoking in the UK over the last forty years. This has largely been achieved by information and persuasion. Behaviour change can work on a whole population level as well as an individual level. Charm offensives can work.

  • My original sentence got mangled by the technology.
    What should have said —
    “A similar theme runs through some of the spy fiction that was omni-present in the 1960s”
    was mangled and merged as —
    “A similar theme runs through some of the spy fiction that was knife sent in the 1960s”

  • Ian Sanderson (RM3) 14th Jan ’15 – 6:23pm

    Oreste Pinto is indeed a fascinating character. He was Dutch and in 1913 in his mid-twenties he was recruited into the Deuxième Bureau. Then later he worked for MI5. I believe he was still in Wandsworth when he died in 1961. Eisenhower whose SHAEF HQ base was on Kingston Hill just up the road from Wandsworth was a great admirer and apparently regarded him as the man who knew more about security than anybody else.

    I wish I knew more about him. My father (who was a longtime in the army) had been aware of him although I am not sure If they had actually met. So we watched the TV programmes together with my Dad occasionally muttering approving remarks, which was unusual because he regarded most films about the second world war as rubbish.

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