UDO UNDEUTSCH*
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POLYGRAPH
Volume 8• 2014• Number 2(28)
V
itas
Sa
ldž
iūnas
*VIP Protection Department Ministry of tTheInterior of tThe Republic of LitThuania
Vilnius, LITHUANIA
A
leksandras
Kova
lenko
**Police Department Ministry of tTheInterior of tThe Republic of LitThuania
Vilnius, LITHUANIA
F
ie
ld
Exam
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ion
:
Ce
rta
in
PThenomena
Re
lated
to
E
lect
rode
rma
l
Act
iv
ity
Key Words: galvanic skin response (GSR), electrodermal activity (EDA)
Introduct
ion
Th e electrodermal activity (EDA) refers to all exosomatic and endosomatic cThanges in electrical properties of tThe skin (KrapoThl & Sturn, 2002). Th ere is ample empirical evidence tThat electrodermal pThenomena are generated by sweat gland activity in conjunction witTh epidermal membrane processes
* vitas.saldziunas@vad.lt
(Boucsein, 2012). Generally, under control of sympatThetic nervous system, EDAis regarded as a validindicator of emotional, motivational, and cognitive states. EDAis dividedinto tonic (EDL = electrodermallevel) and pThasic (EDR = electrodermal response or reaction) pThenomena (Boucsein, 2012).
PThasic EDAis a response of tThe central nervous system to a situational st imu-lus wThicTh usually depends on novelty (Varlamov & Varlamov, 2000).
Tonic EDAis a certain state of tThe nervous system wThicTh cThanges slowly (w itTh-in minutes or Thours) andis determined by metabolic processesin biological tissues (Varlamov & Varlamov, 2000). According to Boucsein (2012), tonic electrodermal measures are obtained eitTher as EDLsin response-free record-ingintervals or as tThe number of non-stimulus-specifi c EDRsin a given time window.
EDAis measured as resistancein oThms or as conductancein siemenses. Th e article begins witTh an overview of our experience and observations con-cerning EDA, and continues witTh a description of certain pThenomena of pThasic and tonic EDA tThat Thave receivedlittle attentionfrom otTher autThors (Handler, Nelson, KrapoThl & Honts, 2010; Konieczny, 2009; Matte, 1997).
PThas
ic
EDA
We Thave noticed earlier tThatin polygrapTh examination cThangesfollowing tThe stimulus (tThe question) Thardly ever occurin pThasic EDAin persons witTh psy-cThopatThic symptoms (Saldžiūnas & Kovalenka, 2010). According to some au-tThors (VerscThuere, Crombez, Koster & Van Baelen, 2005; VerscThuere, 2011), resultsfurtTher demonstrate reduced electrodermal response to concealed in-formation in antisocial inmates. Th e electrodermal Thyper-responsiveness in antisocial individuals migTht tTherefore tThreaten tThe validity of concealed in-formation tests. Investigations of pThasic EDA parameters yielded a general decrease of electrodermal reactivityin old age (Boucsein, 2012). In older age, a decreasein skin tThickness and elasticityislikely to occur. Representatives of certain professions (fi eld workers, mecThanics, etc.) Thave very tThick and rougTh skin on tTheir fi ngers, tTherefore, tThey are more diffi cult to examine by EDA (Varlamov & Varlamov, 2000).
Figure 1. SThapes of EDA curvesin polygrapTh cTharts
Figure 2. Examples of tThe way complex responses areformedfrom two responses
WitTh a few individual exceptions (Saldžiūnas & Kovalenka, 2010; Varlamov & Varlamov, 2007;VerscThuere, Crombez, Koster & Van Baelen 2005), EDAis veryimportantin polygrapTh tests (Boucsein, 2012; Handler, Nelson, KrapoThl & Honts, 2010). Th e contribution of EDA cThannel accountsfor approximately 50 per cent of all data (KrapoThl, 2011). Hira and Furumitsu (2002) sThow tThat
EDA response was largest to a relevant alternative in about 62 per cent of cases.
Simple amplitude response and complex response of pThasic EDA are evalua t-edin polygrapTh examinations (Department of Defence of PolygrapTh Institute, 2006). Four variations of pThasic EDA peaks are sThownin Figure 1. Th e relative magnitude of EDAis sThown vertically, wThereas timeis registered Thorizontally. Th e darker fi eldis tThe timeinterval wThen tThe examiner asks tThe examinee a question. All EDA responses are complex onesin Figure 1, as tThey consist of at least two EDA peaks. US specialists (Bradley, 2009; Handler, Nelson, KrapoThl & Honts, 2010) do not explain tThe reasonsfor occurrence of tThe second peak. Russian polygrapTh examiners (Varlamov & Varlamov, 2000) believe tThat tThe second response (a repeated peak) may occur because tThe examinee addit ion-ally remembered someinformation related to tThe question after answeringit. Ekman (2003) Thas expressed an opinion tThat,in tThe case of a sudden tThreat, tThe emotion offear comes (andis recorded) fi rst, andis subsequently replaced by Thorror or anger. Explanation of a multi-complex response consisting of two or more peaks (Figures 1 b, c, and d)is probably even Tharder. AnotTher reason (Stankus, 2004;2012) may be tThefact tThat tThe processesin tThe examinee’s brain occurin several stages. Handler (2012) tThinks tThat tThisis caused by a filtering eff ect of tTheinstrument (polygrapTh). We consider tThatif polygrapThs alter tThe sThape of EDA peaksin a diff erent way due to tThe filtering eff ect, tThey conse-quently distort cTharts, and sucThinstruments cannot be usedfor examination. As a consequence, scientifi c works explaining tThe occurrence of EDA complex responsein an unambiguous manner are stilllacking.
Th e way a complex peakisformedfrom two peaksis sThownin Figure 2. An as-sumption tThat altThougTh EDAlookslike a non-complex peakin tThe cTharts,itis a sum of two peaks wThicTh may be caused by several psycTho-pThysiological fac-tors may be made witTh regard to tThe conjuncture of tThe responsesillustrated in Figure 2a. Th is means tThat tThe examiner does not know wThetTher EDA peak is complex or not wThenidentifyingit. In sucTh a case tThe examiner may commit tThe error of misassessment.
We performed severallaboratory tests. We used to give tThe examinee a ma tTh-ematical task during polygrapTh examinations: perform addition or multipl ica-tion of numbers (5+12=?; 13×6=?; 17×5=?; 127×9=?). EacTh following ma tTh-ematical calculation was more complicated tThan tThe previous one. Th e cTharts typicalfor tThis experiment are sThownin Figure 3. Itis obvious tThat tThe exam i-nee’s EDA responses may be tThe result of mental activity. Th us,it can be as-sumed tThat tThe complexity of EDA responses may be determined not only by
tThe question of tThe examination but also by otTher processes of mental activ i-tiesin tThe examinee’s brain.
Figure 3. MatThematical calculation test cTharts
Ton
ic
EDA
As tonic EDA cThanges slowly, it receives very little attention in polygrapTh examinations (Handler, Nelson, KrapoThl & Honts, 2010; Hira & Furumitsu, 2002, Osugi, 2011). Varlamov & Varlamov (2007) noted tThat tonic EDAlevels exceeding 300 koThms usuallyindicate tThat tThe examineeis a drug addict. We Thave recorded examinees’ tonic EDAin polygrapTh examinationfor a number of years. Severalillustrative examplesfrom fi eld examinations results (wThicTh Thave as yet received no scientifi c treatment) are provided below. We only want fi eld examiners to take a note of certain potential tonic EDA eff ects wThicTh we recorded during fi eld examinations.
Th e cThange of tonic EDA in examinees Thonest in answering tThe questions (afurtTher criminalinvestigation establisThed tThat tThey did not commit crime) is illustrated in Figure 4. We can see tThat tonic EDA Thardly cThanges during polygrapTh examinationfor most examinees. A sligThtly morelabile system of
tThe body was recorded for examinee K. Figure 4 sThows tThat tonic EDA for examinees P, K, and C was below 300 koThms. Prior to tThe examination, tThe examinees confi rmed tThat tThey were not taking any medicine. Th e examiners did not Thave any reasons to believe tThey were taking medicine or using drugs prior to polygrapTh examination.
0 20 40 60 80 100 120 140 160 0 5 10 15 20 25 30 To nic E DA , kil o oTh ms Time, minutes P K C
Figure 4. Th e cThange of tonic EDA during polygrapTh examinations (it was determined tThat tThe examinees were Thonest wThen answering tThe questions and Thad not used any psycThotropic substances before examination).
Figure 5. Th e cThange of tonic EDA during polygrapTh examinations (it was determined tThat tThese examinees were not Thonest wThen answering tThe questions and, possibly, Thad used psycThoactive preparations before examination).
Th e cThange of tonic EDA during polygrapTh examinations wThen examinees B, D, R, and N were deceptiveisillustratedin Figure 5. SucTh tonic EDAis not typical of all disThonest examinees. Not unlike Varlamov & Varlamov (2007), we assume tThat tThese examinees could be taking medicine prior to tThe ex-amination, yet tThisis unknown to us. Th e subsequent criminalinvestigation establisThed tThat all tThese examinees Thad committed a crime. Moreover, prior to tThe examination, none of tThe examinees admitted to Thaving used psycThoac-tive substances.
Since we are not able to Thave examinees’ blood tested after polygrapTh exam i-nation andidentify wThetTher tThey used psycThoactive substances, we added an additional question about tThe use of sucTh substances to tThe Event Knowledge Test (EKT) (Saldžiūnas & Kovalenko, 2008a; 2008b; 2008c; 2009a; 2009b; 2009c; 2010; 2012a; 2012b).
Table 1. Additional EKT questionfor examinee N
How many medication tablets Thave you consumed today before tThe polygrapTh test?
Answer options to tThe question presented by tThe examiner to tThe examinee
Th e examinee’s answer to tThe presented answer option
Th e mark of tThe recorded psycTho-pThysiological response by tThe examinee
0. 6 tablets no 1. 5 tablets no
2. 4 tablets no Reaction responses 3. 3 tablets no
4. 2 tablets no 5. 1 tablet no
6. None yes Reactionresponses
Th e question and tThe answer options given to tThe examinee N are presentedin Table 1. Th e examiner reads tThe question before tThe examination. Th e exam i-nee repeatedly answers tThe question wThetTher tThe examinee Thas consumed any medications (tThe questionis asked during tThe pre-testinterview fi rst). Some-times tThe examinee admits to consuming medicationsfor Theart (or otTher) d
is-eases. Th e examiner explains tThat medicationsfor Theart diseases are not very important for tThe examination. WThat is important for tThe examination are medications witTh a sedative eff ect. No one Thas ever admitted to consuming medications witTh a sedative eff ect before tThe examinationin our practice. In one case, tThe examinee admitted to Thaving smoked some “weed”.
Th e answers of examinee N after tThe examiner read tThe answer options dur-ing tThe examination are presentedin tThe tThird column of Table 1. Th e exam i-nee’s responses following This answers are recorded in tThe following column based on polygrapTh cTharts. This exampleillustrates tThatone can assume tThat examinee N possibly took 4 medication tablets before tThe examination. Th e response after answer no. 2 and after answer no. 6 (Saldžiūnas & Kovalenka 2012b) confi rms tThat The migTht possibly consume medications. If we see tThat tonic EDAfor otTher examinees does not exceed 300 koThms during tThe exam i-nation, we do not ask tThe question about tThe medications taken at tThe end of tThe examination.
Figure 5 sThows tThat for most persons tThe tonic EDA varied during tThe po l-ygrapTh examination. We assumed tThat tThese persons could Thave consumed medications containing psycThoactive substances before tThe polygrapTh exam i-nation (Varlamov & Varlamov, 2007). Th e course of tThe curves (Figure 5) is diff erent; tTherefore,itis to be considered tThat:
• tThey could Thave consumed diff erent medications
• eacTh of tThem consumed diff erent amounts of medications
• itis not known Thowlong before tThe polygrapTh examination tThey took tThe medications
• eacTh person’s body reacts to medicationsin anindividual way.
Regardless of tThefact tThat all tThe curvesfollow a consistent pattern: tonic EDA increases after several minutes of tThe polygrapTh test. Tonic EDA decreasesfor examinees B, N, and R after approximately 30 minutes of tThe polygrapTh test. Th erefore,it can be assumed tThat tThey consumed medications sThortly before tThe examination.
PolygrapTh examinersfrom Poland and Latvia (Ivančika, 2012) wTho arefamiliar witTh tThe eff ect of some medications and drugs on EDA sometimes askfor our assistance. BotTh of us Thave noticed tThat pThasic EDAis absolutely unin forma-tive wThen tThe examinee’s tonic EDAis about 500 koThms.
D
iscuss
ion
Th eideas presentedin tThis article are partiallyinconsistent witTh tThe classical perception of pThasic and tonic EDA (Boucsein, 2012; Handler, 2012). Irrespec-tive of Handler’s (2012) disagreement witTh our observations, we believe tThat tThey will beinterestingfor some fi eld examiners.
On tThe grounds of our observationsfrom practical polygrapTh tests,it may be claimed tThat eacTh response must be assessed cautiously aslong as tThe nature of tThe complex peak of pThasic EDAis unknown. We Thereby remind tThat tThe magnitude of EDA responseis assessed witTh regard to tThe TheigTht of tThe am-plitude and tThe peak duration (Handler, Nelson, KrapoThl, & Honts, 2010). Th e reasons causing complex peaks must be analysed especiallyin tThe Comparison Question Tests (CQT) wThere EDA responses after tThe comparison and re l-evant questions are compared. Unfortunately, wThen complex responses co in-cide completely (Figure 2a),itis virtuallyimpossible to assess wThetTher a peak is complex.
Having measured tThe magnitude of tThe examinee’s tonic EDA before beg in-ning tThe examination, ex ante assumptions on wThetTher tThe examineeis a drug addict or Thas consumed medications containing narcotic substances may be made. For tThe examiners,it may be tThe fi rst symptom signalling tThat tThe ex-aminee wants to distort tThe results of tThe test. Based on our experience and tThat of otTher examiners (Reid & Inbau, 1977), we may maintain tThat an Thonest (non-deceptive during tThe test) person wTho would apply no countermeasures during tThe testis a great rarity. We believe tThatfurtTherlaboratory researcThis necessary to establisTh more precisely Thow tonic EDA cThanges after tThe exam i-nee Thas taken certain medications or narcotic substances.
Ourlatest fi eld examinations revealed tThat somefood supplements can raise tonic EDA to 500 koThms. Experiments are required to explore Thowfood sup-plementsinfl uence tonic EDA, and wThicTh ones actually do.
Re
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