Every evening, Wilmington daily commercial. (Wilmington, Del.) 1878-1928, 1922-07-08
LIARS AND BLOOD PRESSURE

washington. July s,--Soms day |
every prisoner Mt tho bar may have |
his story scientifically tested Tor |
truthfulness. Blood pressure has been |
tried and proved ms gauge OF de-
ceptlon, and a method has been evolv-
ed by which an expert can test with
reasonable exactness the truth OF the
spoken word.
Thus n prisoner may recount calmly
n plausible abb for a crime. Per-
haps he shows no visible symptoms
OF fear or nervousness. But IL ne IN
not telling the truth his blood pres-
sure. over which no has no control,
Ia reacting violently TO the fear OF
discovery. On the other hand, II no
,s telling the truth, however fantastic,
his blood pressure will bear him out
by remaining at q comparatively nor
mai level.
Tho blood pressure deception test
has been developed 20 practical
stage. II was used by tho Depart
nent OF Justice In connection with
wartime Spy cases. II Ia being used
now by O. criminologist Of the Berkeley.
California. police department.
Here In Washington tho man who
developed the tset has just tried u on
n negro accused Of murder. Evidence
is against the suspect. but the test
Indicates that his alibi is correct. lie
lis now being held while other sus-
poets are being trailed.
, This illustrates the place which the
-
hold in criminal investigation u Will
mot be taken az absolute proof Of guilt
| or innocence. But in a case where
; tho evidence would convict man IN
spite Of his plea OF innocence the de-
ception test may lead 20 further IN
ouirv into other clues. with the test
, IN use railroading man 30 Jail may
{ be no longer A frequent occurrence.
Tho pioneer Of the blood pressure
deception test Is Or. William NJ. Mars
a ton, professor ~ psychology ~ the
. American University. Dr. Msrstor
4 SAYS that there has been some mis-
, understanding about his work. ~
q uses three different kinds Of deception
, tests Of which tho blood pressure tes
In the most reliable. All Of the in.
. struments adapted for 80 In givint
l. the tests we're invente /some time ag'
. for various purposes. Or. Marstoi
A explains that he IS the inventor Of tn
3 blood pressure test, but not Of the in
3 strument.
y The Deceptive Complex.
Working at the Harvard IAborator-
in 1913, he evolved the theory tina
. blood pressure il an indicator Of de
z ceptIon. Fear and anger largely con
N stitute the deceptive complex. an
81, these are the only emotions that IN
= huence 20 any extent systolic bloc
pressure on which the tests are based
y DR.. Marston found BY experiment
=. that II anyone attempts 20 deceive In
n emotion Of fear Influences his bloc
IA pressure IN definite ways. Even
"a the possibility Of detection IS rennOt
n the organs responded somewhat 10 a.
"a inherent fear. II il not normal 70 Il
4 and this departure from normal IA
h. its reaction in the blood pressure.
ir Using an instrument which "a al
taohed 10 the arm. and which ne calls
4? sphygrn omanometer, the psychology
K made numerous tests which sI6taine
III his theories. Tests were made OF pei
M SONS held by the police deparJmeI
for theft. drug taking, prostitution, fo
m gerry, and bootlegging. After each te'
p was made DR.. Marston gave his verdi
y as 20 the truth or falsity OF the sui
tect's account. Then the investigate
was continued by medical examln.
ton, questioning other persons invOl'
81 1.a-a
is claimed that the blood pressure tes
were invariably substantiated By y
corrobOrative evidence.
Die DR.. Marston says that he has alwa,
irt got 100 per cent satisfactory results
n making the tests himself. That is.
le, him the sphy gmomanOmeter has pro
an ed 100 per cent reliable as a detect
Of deception Other operators. less ale
ng to psychological factors in case, a.
ed less experienced in making examin
tons, have been getting from 50
led 100 per cent satisfactory results.
It IS not simple matter 20 give
-" deception test. From q description
the method it Is readily apparent "
the an expert must give It Il it : 10
e. u any value.
Lite. \ woman may have d normal bio
pressure OF 800. The sphygmomar
meter IS fastened 70 her arm and I
m operator listens in. Whether the =
} IS questions ara connected with the c.
oss or net the subjects pressure woI
TEL probably jump 10 1870 and remain the
\ novice might at once conclude Il
the subject was not answering his gu
to tons truthfully, whereas this react
Ond would probably be due 20 gene
lall uneasineSS at the mysterious proce'
ing. AS the questions proceed the
orator may find that the chart ne
eli? drawing renls ms at a level Of 1870
D drops of toward normal. indicat
ght that the subject IS truthful in
Ing statements.
- Outside Influences Noted
On the other hand. the pressure Il
suddenly rise. even reaching q peak
un- 40 or $50 when significant questi'
lent ara answered This would generally
lem dictate a deception curve: not n
essarily, however To make an
travagant illustration. suppose that
lus- as an important question Is as
lteo a. ferocious gorilla should leap throl
we the window. This would have moth
sted n do with tho casa but the ss,bJe
blood pressure would rise TO a reco
breaking peak.
- The tests are given in a room
from disturbance, but even so the a
toner has to watch for outside in
ences that might affect the chart.