Brain Forensics

Inside
BrainSource

The American judicial system is an adversarial process that aims to fairly resolve civil disputes between plaintiff and defendant. In criminal courts, the aim is to justly determine a defendant’s guilt in breaking the law, charges of which are brought by the prosecution.

By "adversarial" the system relies on forensic (arguable) evidence that supports one side or diminishes the other. Forensic opinion, in general, relies on an array of admissible evidence and expertise, only some of which may be scientifically or objectively based. Circumstances, fallible eye-witness, deduced motives, logical and impassioned argument, social beliefs, and fragments of sundry evidence, which one side or other claims relevant, constitutes considerable forensic presentation.

The aim of forensic neuropsychology is to contribute objective and scientifically-founded clinical evidence in a judicial proceeding where brain and behavior issues exist. While each side of a case, the prosecution and defense, or the plaintiff and defense, may present their own—and differing—neuropsychological evidence, in an ideal situation there should be sufficiently incontrovertible scientific foundation of evidence. Unfortunately, even with similar foundation, each side may reach different conclusions. There is, as yet, no way to remove the bias of personal beliefs, the emotions of personal experience, and the incompleteness of scientific methodology and findings.

To enable as fair and sound a basis as possible for forensic evidence, findings from scientific research must prevail. Of course, much scientific research is open to criticism for methodology or some inadvertent bias that taints objectivity or generalizability. This is why scientific evidence must reflect aconvergence of evidence that reveals a measure of consistency in support or rejection of a forensic issue.

Any time the condition of the brain becomes an issue in a civil or criminal case, it is incumbent on the brain-behavior expert—usually, the neuropsychologist—to be able to support every piece of his or her evidence with scientific foundation.

The brain-behavior specialist contributes state-of-the-art-and-science perspective in assisting in answering the following questions:

	Is (or, was, at the time of the crime, in the case of a criminal proceeding) the brain functioning within culturally accepted standards of normal?
	If so, what constraints and variations in brain functions might coalesce with non-neurological factors to bear on psychological processes (such as anger and impulse control, personality disorders, memory reliability, suggestibility, and decision-making) leading to criminal or abnormal behavior?
	If not, what are the dysfunctional systems of the brain that might account for abnormal behavior affecting an individual's adjustment in society?
	What neuropathology can account for and cause dysfunctional systems?
	What are the practical effects of the dysfunction on emotional, vocational, family, and personal behavior?
	What is the status of the dysfunction and neuropathology (that is, what is the permanence or potential for recovery)?
	What circumstances regarding brain functioning might help account for criminal behavior?

Reliable, valid, and scientifically accepted means to answer these questions form the basis for expert testimony—forensic neuropsychological (brain-behavior) evidence. The clinical neuropsychologist has been qualified as an independent expert in most, if not all, jurisdictions. By virtue of his or her professional training (Ph.D. or Psy.D. degree), experience, specialization, and professional recognition (usually, ABPN or ABCN Board certification) the neuropsychologist can provide the most learned assistance in understanding brain and behavior relationships.

If ours were a perfect world we would be able to sort out the variables that determine a human condition or a human behavior, weight each according to some neurological importance, and reach a definite and incontrovertible conclusion. Forensic neuropsychology depends on sorting out as many of the relative and reliable variables as science has revealed so far, assigning weights according to best estimates of importance based on scientific research, and concluding with a probabilistic statement.

The judicial system is bent on resolution, not on probabilities. Therefore, the strength of argument that supports (particularly a weak) probability determines the win or loss of the case.

Admissibility of scientific brain-behavior evidence in court proceedings is based upon several rulings:

	Evidence is based on generally accepted techniques and methods within the scientific field (Frye v. United States, 1923),
	A witness is determined to be an expert in a field based on knowledge, skill, experience, and education (Federal Rules of Evidence, Number 702 and 703), and
	Expert testimony is founded in scientific methods that are relevant, reliable, and valid (Daubert v. Merrell Dow Pharmaceuticals, 1993).

Brain-behavior diagnoses and explanations of normal versus dysfunctional brain systems rely on:

	The wealth of empirical, normative, and comparative brain-behavior research accumulating over the past three decades,
	Quantitative and objective neuropsychological assessment techniques to evaluate an individual’s brain functioning,
	Broad and multidisciplinary foundation for logical interpretive strategies for inferring neuropathology, and
	Cognitive and behavioral patterns that explain specific acts and competencies (or lack thereof).

The forensic brain-behavior expert is expected to:

	Offer opinions backed by reliable and valid scientific findings,
	Account for possible or potential conflicting or incongruent bases for conclusions,
	Integrate cross-discipline findings and explain, based on scientific foundation, consistencies and discrepancies,
	Rely on standardized and actuarial assessment practices to derive functional and practical conclusions,
	Sort out complex data from which clinical inferences are derived into manageable, understandable categories,
	Use assessment procedures that are ecologically relevant (i.e., real-world practical), that support diagnoses and reveal practical, relevant functional weaknesses or losses,
	In the absence of robust objective evidence to explain a potential brain-behavior relationship, rely on accepted theory drawing from multidisciplinary fields of neuropathology, developmental neuropsychology, neuropharmacology, and related fields,
	Explore and explain ancillary and potentially confounding issues of malingering and premorbid influencing factors, and
	Use available empirical studies of ecological implications of assessments and theoretical and experimental bases, to describe brain-behavior relationships in terms of practical and reliable consequences.

The field of brain forensics demands professional responsibility, breadth of scientific knowledge, resourcefulness to draw from multidisciplinary fields to strengthen conclusions or resolve data conflicts, highest standards of ethical and objective principles, and resolve to contribute integrity to the judicial system to preserve respect for uncompromised rights to fair and just treatment.

These resources reflect professionally accepted standards in brain forensics:

The Practice of Forensic Neuropsychology, Robert J. McCaffrey, Arthur D. Williams, Jerid M. Fisher, and Linda C. Laing, editors, Plenum Press, 1997.

Psychological Evaluations for the Courts, Gary B. Melton, John Petrila, Normal G. Poythress, and Christopher Slobogin, The Guilford Press, 1997 (second edition).

Brain Imaging in Substance Abuse: Research, Clinical, and Forensic Applications, M. J. Kaufman and J.Frascella (Eds.), Humana Press, 2001.

The Forensic Evaluation of Traumatic Brain Injury: A Handbook for Clinicians and Attorneys, G. J. Murrey, J. Yedid, J.A. Davis (Eds.), CRC Press, 2000.