EEG Lie-Detection Countermeasures

[David Ruhl]

Stumbled across this, thought it may be of interest:


Simple, effective countermeasures to P300-based tests of detection of
concealed information.

Rosenfeld JP, Soskins M, Bosh G, Ryan A.

Department of Psychology, Northwestern University, Evanston, Illinois
60208, USA. jp-ros...@northwestern.edu

We found countermeasures to protocols using P300 in concealed
information tests. One, the "six-probe" protocol, in Experiment 1,
uses six different crime details in one run. The countermeasure:
generate covert responses to irrelevant stimuli for each probe
category. Hit rates were 82% in the guilty group; 18% in the
countermeasure group. The average reaction time (RT) distinguished
these two groups, but with overlap in RT distributions. The "one-
probe" protocol, in the second experiment, uses one crime detail as a
probe. Here, one group was run in 3 weeks as a guilty group, a
countermeasure group, and again as in Week 1. COUNTERMEASURE: Covert
responses to irrelevant stimuli. In Week 1, hit rate was 92%. In Week
2, it was 50%. In Week 3, 58%. There was no overlap in the irrelevant
RT distribution in Week 2: Countermeasure use was detectable. However,
in Week 3, the RT distributions resembled those of Week 1; test-
beaters could not be caught. These studies have shown that tests of
deception detection based on P300 amplitude as a recognition index may
be readily defeated with simple countermeasures that can be easily
learned.

Psychophysiology. 2004 Mar;41(2):205-19.

http://www.ncbi.nlm.nih.gov/pubmed/15032986?dopt=Abstract


Via a blog about the psychology of deception:
http://deception.crimepsychblog.com/

[GilZ]

brain: 2, machine:0 (polygraph and P300), so far.
Who's next?

Gilberto. (no, I'm not next. It's just my closing)

On Feb 20, 9:54 pm, David Ruhl <D.A.R...@gmail.com> wrote:
> Stumbled across this, thought it may be of interest:
>
> Simple, effective countermeasures to P300-based tests of detection of
> concealed information.
>
> Rosenfeld JP, Soskins M, Bosh G, Ryan A.
>
> Department of Psychology, Northwestern University, Evanston, Illinois

> 60208, USA. jp-rosenf...@northwestern.edu

[Shawn Taylor]

Yes, but which is less bad? We use polygraphs now, would it be better
to use P300? Should the referenced paper be taken to say "don't use
P300" or "don't use P300 three weeks in a row?" What about other EEG
markers used in conjunction with P300? Would that be more reliable
than a poor polygraph operator?, a good one?
-shawn

[GilZ]

P300, yes, the latter, sounds like something interesting to
investigate, yes, hopefully.