a novel, countermeasure-proof, p300-based protocol for detection of concealed information
DESCRIPTION
A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information. J.Peter Rosenfeld, Michael Winograd, Elena Labkovsky, Ann Ming Lui Department of Psychology Institute for Neuroscience Northwestern University. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/1.jpg)
A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information
J.Peter Rosenfeld, Michael Winograd, Elena Labkovsky, Ann Ming Lui
Department of PsychologyInstitute for NeuroscienceNorthwestern University
![Page 2: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/2.jpg)
Previous P300 DD protocols used Separate Probe(P),Irrelevant(I) and Target(T) trials.
80% to 95% correct detection rates….but….
*Rosenfeld et al. (2004) and Mertens, Allen et al. (2007):These methods are vulnerable to Counter-measures (CMs)
via turning I’s into covert T’s.
![Page 3: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/3.jpg)
Results from Rosenfeld et al. (2004): Farwell-Donchin paradigm(BAD and BCAD are 2 analysis methods.)Diagnoses of Guilty
Guilty Group Innocent Group CM Group
9/11(82%) 1/11(9%) 2/11(18%)
Amplitude Difference (BAD) method,p=.1
Cross-Correlation(BC-AD) Method, p=.1
6/11(54%) 0/11(0%) 6/11(54%)
![Page 4: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/4.jpg)
Results (hit rates) from Rosenfeld et al. (2004): Rosenfeld paradigm
Week BAD* BC-AD*
1: no CM 12/13(.92) 9/13(.69)
2: CM 6/12(.50) 3/12(.25)
3: no CM 7/12(.58) 3/12(.25)
*Note: BCD and BAD are 2 kinds of analytic bootstrap procedures.
![Page 5: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/5.jpg)
In the “Complex Trial Protocol,” P/I and T/NT decisions are separated:
Two stimuli per trial, 1.2-1.5 s apart. The first is P or I presented in white
font. The second is the same P or I
presented either in T color (green) or one of 4 non-T colors (red, yellow, etc.)
(The second could also be T and NT numbers, or whatever.)
![Page 6: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/6.jpg)
![Page 7: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/7.jpg)
4 STIMULUS TYPES
STIMULUS TYPE NUMBER PROBABILITY
Probe Target 30 .09 Probe non-Target 30 .09 Irrelevant Target 30 .09 Irrelevant non-Target 240 .73
All Probes 60 .18 Oddballs 90 .27
One probe and 4 irrelevants
P (T/P) = .5… vs… P (T/I) =.11 (Confound?)
![Page 8: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/8.jpg)
DESIGN: as in ’04 paper, Exp. 2: 3 weeks in one group Week 1 Naïve Week 2 CM Week 3 Repeat Week 1 One block with one probe type, but
category varied and counterbalanced across subjects/weeks: 1)mother’s first names 2) family surnames 3) home towns
Main Study plus near replication. Innocent Control Group for FPs.
![Page 9: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/9.jpg)
Countermeasures in Week 2: Also as in ’04 paper
Left finger press to Irrelevant # 1 Left toe wiggle to Irrelevant # 2 Right toe wiggle to Irrelevant # 3 Imagine Prof slaps you for Irrelevant#4 All these are done covertly so that
operator cannot detect them.
![Page 10: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/10.jpg)
![Page 11: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/11.jpg)
![Page 12: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/12.jpg)
RTs (all stimuli). Replication like ‘04 study: no overlap.
![Page 13: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/13.jpg)
P & I Individual RTs in CT Protocol (Flat liner at bottom did not beat test.)
![Page 14: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/14.jpg)
Statistical tests within each subject:
T/F-tests comparing Week 1 RT or RT Variance versus Week 2 are all p<.01, and < .001 in the one subject who beat the test in Week 2.
Thus CM use is detectable.
![Page 15: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/15.jpg)
In ’04 paper (old protocol), probe declines over weeks:
0 1 2 3 4WEEK
200
300
400
500
600
700
AM
PLI
TU
DE
,p-p
, co
mpu
ter
u nits
.
IRRELEVTARGETPROBE
![Page 16: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/16.jpg)
NEW RESULTS: P300s
![Page 17: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/17.jpg)
P300, p-p
![Page 18: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/18.jpg)
Two* possible (P-I) tests:
1)Traditional: Probe versus mean of all Irrelevants, P vs I-All.
2)Probe versus Maximum Irrelevant P vs I-max (“simple hit”) or Probe
versus I-max not associated with elevated RT (“RT-screened Hit”).* at .9 or .95 confidence levels.
![Page 19: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/19.jpg)
Main Study. Within-subject correct detections of guilty subjects based on bootstrap comparison of probe P300 against the average of all irrelevant P300s over 3 weeks.
WEEK Hit Rate [Hit Rate] Week 1 (no CM): 11/12 (92%) [12/12*( 100%)] Week 2 (CM): 10/11 (91%) [11/12* (92%)] Week 3 (no CM): 11/12 (92%) [12/12* (100%)]
Main Study: False positive(FP) group. Confidence=.9 Confidence=.95 Test FPs Hits A’ FPs Hits A’ Iall .08 .92 .95 0 .92 .98 Imax 0 .92 .98 0 .92 .98
![Page 20: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/20.jpg)
Main Study: Simple and RT-qualified diagnoses (at confidence = .9, Probe vs. Imax (or RT-qualified Imax) across 3 weeks (n values in parentheses). CM use also shown.
Week 1 (12) Week 2 (11) Week 3 (12)
Simple hits .92 .73 .92
Hits/RT qualified .92 .91 .92
CM use 0.0 1.0 0.0
![Page 21: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/21.jpg)
Near Replication: Within-subject correct detections (“Hits”) of guilty subjects based on bootstrap comparison (at 2 confidence levels) of probe(P) P300 against the average of all irrelevant P300s (I-All) over weeks, and against the largest irrelevant P300 (I-Max).
CONFIDENCE LEVEL: 0.90 WEEK P vs I-All: Hits, [FPs], A’ P vs I-Max: Hits,
[FPs] A’ 1: 12/12 (100%),[8%] .91 11/12 ( 92%), [0%]
.98 2: 12/12 (100%) 11/12 ( 92%) * 3: 9/10 (90%) 7/10 (70%)
CONFIDENCE LEVEL: 0.95 WEEK P vs I-All: Hits, [FPs], A’ P vs I-Max: Hits, [FPs],
A’ 1: 11/12 (92%),[0%] .98 11/12 ( 92%), [0%] .98 2: 12/12 (100%) 11/12 ( 92%) * 3: 9/11 (82%) ** 8/11 (73%)**
![Page 22: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/22.jpg)
CTP Mock Crime Study: Preliminary Results. Note Target= 11111. (Mike Winograd’s study)
![Page 23: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/23.jpg)
Conclusions (& Why ? ) The complex trial protocol is CM-
resistant and accurate in the CIT Context.
*The S1 involves no classification or decision, unlike older protocols, whose target classification task is removed, leaving all resources devoted to probe/irrelevant recognition.
*CMs force more attention to first stimulus increased probe (& Irrel) P300s.
![Page 24: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/24.jpg)
NEXT? We need to extend CTP to our
hybrid CQT screening protocol (Rosenfeld et al., 1991.)
We need to try 3-4 blocks a session, each with different probe category.
CTP should be even better with more Irrelevants.
![Page 25: A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Concealed Information](https://reader035.vdocuments.net/reader035/viewer/2022081603/56813532550346895d9c99de/html5/thumbnails/25.jpg)
A Novel, Countermeasure-proof, P300-Based Protocol for Detection of Deception (DD).