Lecture 21: Neuroscience and the Law Flashcards
Two legal criteria are especially relevant to use of cognitive
neuroscience evidence for determining criminal responsibility
Insanity
Mens rea
Mens rea
mental component of a crime (as opposed to
‘actus reus’, the physical act of committing the crime).
Intention: did the individual intend to commit the crime?
Knowledge: did the individual know that harm would result?
Risk: did the individual know that the act was risky and could result in
harm?
Negligence: should the individual have known about risk even if they
didn’t?
Applications to Psychopathy
‘A person is not responsible for criminal conduct if at the time of such conduct as a
result of mental disease or defect he lacks substantial capacity either to appreciate
the wrongfulness of his conduct or to conform his conduct to the requirements of
the law’ (Model Penal Code of American Law Institute; not law itself, but serves
as basis for changing/enacting laws in many states).
Aharoni et al. (2008) note that the Model Penal Code was
modified so as not to excuse psychopaths:
“…the terms ‘mental disease or defect’ do not include an
abnormality manifested only by repeated criminal or otherwise
antisocial conduct.”
Symptoms of Psychopathy
Societal Cost of Psychopathy?
Facts about Psychopathy:
* .05-1% of general population meet criteria
* 15-25% of criminals meet criteria for psychopathy
* Psychopaths commit more offenses than other
criminals
* Psychopaths commit 4x as many violent offenses as
other criminals
* Psychopaths are estimated to account or 30-40% of all
violence in society (not attributed to gangs, war, etc)
Brain Dysfunction in Psychopathy?
Researchers have postulated that psychopaths are
characterized by abnormalities in various brain regions.
* Kiehl (2006, Psychiatry Research) has advanced the
“paralimbic” hypothesis of psychopathy: proposes that
multiple regions within and adjacent to the limbic system are
dysfunctional, including the amygdala and ventromedial
prefrontal cortex.
* These regions are thought to be underreactive to emotional
and other salient stimuli, including moral violations.
Moral decision making activates
social/emotional regions,
including ventromedial PFC, amygdala
Moral Decision-Making Deficits in Psychopaths
Increased moral picture > non-moral picture response in ventromedial
prefrontal cortex, previously implicated in moral decision making, in
nonpsychopaths but not psychopaths
Reward processing and psychopathic traits
Psychopaths have substantially increased risk of substance abuse problems.
Dopmaine reward system has been linked to substance abuse problems.
These observations led Buckholtz et al. (2010) to hypothesize that psychopathic traits
(measured by a standard scale similar to PCL-R) would be associated with
dysregulation of dopamine reward circuitry – specifically, nucleus accumbens (NAcc).
Community sample of 30 adults (aged 18-35 yrs) without history of drug abuse.
Used PET to examine dopamine release in NAcc during administration of amphetamine
versus placebo (PET can be used to examine activity in dopamine receptors).
Used fMRI to examine brain activity in NAcc during monetary reward anticipation task
(on reward trials, told that they could win money on upcoming trial by pressing a button
while target on screen, vs. trials where no money at stake; brain activity measured
during anticipatory phase, prior to pressing button, and compared for win vs. no
money trials.)
Impulsive-antisocial traits positively correlated
with NAcc activity during reward anticipation
Psychopathy associated with weaker connectivity
between
NAcc and vmPFC
Weaker connectivity between NAcc and vmPFC associated with stronger
(i.e., more dysregulated) NAcc response to subjective value
A recent study of community adults provides evidence for increased
volume of NAcc and other regions in the striatum in individuals who
score high on psychopathic traits
the evidence strong enough to admit in court?
Two key criteria for admissibility
Frye and Daubert standard
Frye standard: is the method used generally accepted in the
relevant scientific community?
Daubert standard: is the method tested, peer-reviewed and
published, does it have a known error rate, is it generally
accepted in the relevant scientific community?
Lie Detection: From the Polygraph to FMRI
Traditional polygraph involves
measuring emotional arousal via SCR, respiration, and related responses to target and control items.
Highly controversial
No Lie MRI, Inc.
rovides unbiased methods
for the detection of deception and other
information stored in the brain.
The technology used by No Lie MRI represents
the first and only direct measure of
truth verification and lie detection in
human history!
No Lie MRI uses techniques that:
Bypass conscious cognitive processing
Measure the activity of the central
nervous system (brain and spinal
cord) rather than the peripheral
nervous system (as polygraph testing does)
Guilty Knowledge
Test
The Guilty Knowledge Test (GKT) is a psychophysiological questioning technique that can be used as part of a polygraph examination which purports to assess whether suspects conceal “guilty knowledge” by measuring their physiological responses while responding to a series of multiple choice questions.
Eyewitness Misidentification and Wrongful Conviction:
DNA Evidence
“DRM” Paradigm
The Deese-Roediger-McDermott (DRM) paradigm represents a conventional experimental methodology for examining false memories; this paradigm involves the presentation of associated words (bed, rest, etc.), which induce a false recall and/or false recognition of a non-presented word (critical lure; sleep).
true>False recognition fMRI activity in left temporal (b&c) and
parietal regions (a) implicated in auditory/phonological
processing, following purely auditory study of DRM lists
detecting individual memories through the neural decoding of memory states and past experience
Key questions: Could a multi-voxel pattern classifier that had been
trained to discriminate brain activity linked to successful and
unsuccessful face recognition based on group data from an old/new
recognition task distinguish brain activity in individual participants
for individual faces, based on
1) Subjective recognition: e.g., brain patterns observed when
participants responded “old” vs. ”new”?
or
2) Objective status of a face: e.g., whether a face was actually old
or new when participants’ subjective responses were the same (e.g.
‘old’ to an old face (Hit) vs. ‘old’ to a new face (FA).
