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The persuasive power of false confessions

10 Post author: matt 11 December 2009 01:54AM

First paragraph from a Mind Hacks post:

The APS Observer magazine has a fantastic article on the power of false confessions to warp our perception of other evidence in a criminal case to the point where expert witnesses will change their judgements of unrelated evidence to make it fit the false admission of guilt.

The post and linked article are worth reading… and I don't have much to add.

Comments (4)

Comment author: SilasBarta 11 December 2009 04:21:06PM 1 point [-]

Wow, that sucks. Note to fingerprint experts: P(fingerprints|guilt) is not the same thing as P(guilt|fingerprints,confession). You don't get to use the latter for the former. That's an information cascade.

Comment author: ChristianKl 13 December 2009 11:41:06PM 0 points [-]

This simply shows that it's very important to get your priors right.

Comment author: wedrifid 14 December 2009 05:55:42AM *  2 points [-]

This simply shows that it's very important to get your priors right.

No, it shows it is very important to get an attorney and then say nothing.

ETA: The Miranda Warning wikipedia page is useful in as much as it explains just how much right you have to remain silent in a particular jurisdiction. For example, the Australian Miranda equivalent* is similar but adds the obligation for audio or video taping. The English equivalent is somewhat less reassuring. Apparently English juries are allowed to infer guilt if you don't talk, thanks to the Criminal Justice and Public Order Act 1994. They are apparently even allowed to infer guilt if you don't answer immediately but choose to answer later. Fortunately for Australians when our various states considered adopting changes based of the 'You Are Probably a Criminal If You Don't Talk and Public Order Act' they all rejected them.

* The term 'Miranda rights' comes from the Supreme Court decision in the case of 'Miranda vs Arizona'. The Australian rights were first upheld in the High Court in the case "Petty vs The Queen". Yet we don't hear the term 'Petty rights', even though I pretty much advocate sticking to them to the point of pettiness so the interviewer doesn't have an incentive to pummel away at your boundaries and so your brain doesn't get confused into thinking what is going on is in any way a conversation. Rapport is not your friend here, they are better at it than you and have explicitly higher status in the context. Of course, there was co-defendant in that case, "Petty vs The Queen, Maiden vs The Queen". 'Maiden Rights' sounds like what you feel entitled to if you were victorious in the annual jousting tourney.