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Interdisziplinäre
Forschungsgruppe Forensische Psychophysiologie
an
der Johannes Gutenberg-Universität Mainz
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Gamer, M. (2010). Does the Guilty Actions
Test allow for differentiating guilty subjects from informed innocents?
A re-examination. International
Journal of Psychophysiology, 76, 19-24. [pubmed]
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The Guilty Actions Test (GAT)
is a scientifically validated technique of forensic psychophysiology
that allows for the detection of concealed memories. However, it is
still debated whether it is better suited for differentiating guilty
from informed innocent examinees than the Guilty Knowledge Test (GKT).
Participants of the current study either committed a mock crime or they
acquired crime related knowledge by indirectly witnessing it on video.
A subsequent polygraph test was carried out using the passive GKT or
the active GAT question wording. Neither electrodermal, nor respiratory
or heart rate responses were found to differ as a function of truth
status or questioning technique. Results indicate that either
questioning technique yields high validity coefficients in detecting
crime related knowledge. Neither the GKT nor the GAT seems to allow for
a valid differentiation of guilty participants and informed innocents
when crime related knowledge is deeply encoded and participants are
motivated to pass the test.
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Gamer, M.,
Kosiol, D., & Vossel, G. (2010). Strength of memory encoding
affects physiological responses in the Guilty Actions Test. Biological Psychology,
83,
101-107. [pubmed]
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The Guilty Actions Test (GAT)
is a valid and scientifically sound technique of forensic
psychophysiology that allows for the detection of concealed memories.
However, its application has been challenged because the results might
be affected by the culprit's forgetting of crime details as well as the
leakage of information to innocents. In the current study, these
aspects were examined by varying the amount of time between a mock
crime and the subsequent GAT, as well as by contrasting culprits with
informed innocents. It turned out that culprits specifically forgot
peripheral crime details during a period of 2 weeks whereas informed
innocents showed similar forgetting for all details. As a consequence,
GAT validity based on electrodermal, respiratory and heart rate
measures remained temporally stable for culprits whereas the amount of
false positive errors for informed innocents decreased as a function of
time. These results indicate that the process of memory encoding and
consolidation has significant effects on the physiological response
pattern in the GAT.
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Gamer, M.,
& Vossel (2009).
Psychophysiologische Aussagebeurteilung: Aktueller Stand und neuere
Entwicklungen. Zeitschrift
für Neuropsychologie, 20, 207-218.
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Ziel
der psychophysiologischen Aussagebeurteilung ist die Differenzierung
von Tätern und Unschuldigen auf der Basis physiologischer
Reaktionen auf spezifische Fragen. Die beiden wichtigsten
Befragungstechniken, der Kontroll- oder Vergleichsfragentest sowie der
Tatwissentest, werden im vorliegenden Artikel dargestellt und
hinsichtlich ihrer Testgüte miteinander verglichen. Dabei wird
insbesondere die individualdiagnostische Eignung
„klassischer“ polygraphischer
Kenngrößen, die auf der Aktivität des
autonomen Nervensystems beruhen, diskutiert. Anschließend
werden neuere Ansätze, die auf der Messung der
Gehirnaktivität mittels Elektroenzephalogramm oder
bildgebender Verfahren beruhen, vorgestellt und kritisch
gewürdigt. Während die letztgenannten Techniken
derzeit noch nicht praktisch einsetzbar sind, steht mit dem
Tatwissentest ein Verfahren zur Verfügung, das auf der
Grundlage peripherphysiologischer Variablen eine valide Diagnostik von
Tatwissen ermöglicht und damit das forensische
Methodeninventar sinnvoll ergänzen könnte.
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