The distance d from PI = (3, -4) to P 2 = ( -2, 1) is d =

EXPERT TESTIMONY (book notes) History ● Jenkins vs. United States Admissibility ● Frye Standard = ​ Fry vs. United States ○ If a scientific procedure or theory was generally accepted by a particular scientific field ○ Probative value: ​a piece of info helps prove a particular point or is useful in deciding an issue before the court ○ Prejudicial: the potential damage of bias a piece of evidence or testimony may cause ○ Balancing act ■ Expert testimony must be more beneficial than biasing ● Daubert vs. Merrell Dow ○ Junk science: ​expert testimony on issues that were not well established in the scientific community but were useful to the legal system in some manner ○ Frye general acceptance test was not the proper rule Challenges to Expert Testimony ● Cross-examination ○ Discrediting an expert witness ● Opposing expert ○ Leaves the judge and jury confused ○ Decrease the impact of the defense’s expert witness ● Judicial instructions ○ A way to influence jurors regarding their evaluation of expert testimony Factors That Influence Expert Witness Credibility ● Dressing professionally ● Good eye contact ● Good composure ● Hired gun effect: ​making experts appear less credible because the experts have been paid by a given side to testify ○ Highly paid experts who testified frequently were less believable and less liked by jurors ○ More likely to believe experts from their local community ■ Experts who actively practice ■ Experts who are paid nothing Criticism ● Taking over the courtroom ● Ultimate Issue Testimony: ​ expert not only gives a conclusion but answers the ultimate legal question that is presently before the court ○ Beyond the role of an expert in mental health ○ Psychology is still divided on the appropriateness of ultimate issue testimony ● Corruption of science ○ The legal system and psychology is very different ○ Financial incentives ○ Extra-forensic relationship ■ Biased testimony ○ Attorney pressure ○ Political and moral beliefs ■ Ex. abortion or conservative ○ Notoriety ■ Receiving public acclaim can be very attractive ○ Competition ○ Lack of recognition or bias Ethics of the Expert ● Competence ○ Psychologists have to stay within their scope of practice ■ Education ■ Training ■ Experience ○ Avoid practicing as a lawyer ○ Does not mean knowing everything ● Informed consent and confidentiality ● Financial arrangements ○ Psychologists should not perform forensic services on a contingency fee: money based on the conclusion ● Multiple relationships ○ Being both a treating therapist and a forensic evaluator Syndrome Evidence ● Look at a specific area in which a great deal of controversy exists both from a legal perspective and from a psychological perspective ● Psych info that is useful in one context is questioned if used in another context ● Syndrome: ​ a set of symptoms that occur together in a meaningful manner and typically have a triggering event ● Profiles: more specific ○ Used to predict behavior because someone matches a particular list of characteristics drawn from the syndrome ● Initially used in courts to explain unusual behavior by a victim in order to educate the jury ● Based on clinical experience and not extensive research ● A high number of people may be identified with a syndrome when they don’t have one ● Substantive evidence: ​used to prove the guilt or innocence of the criminal defendant ● Character evidence: ​not allowed unless the defense opens the door by claiming the defendant is of upstanding character