Notices & Reminders! Midterm #1 Some student’s marks have gone up! I had not included suspect vulnerabilities as one of the problems with the Reid Model (If you included this in your answer your mark went up) Thank you to the student who pointed out this mistake Midterm #2 October 29th 60 multiple choice (60%) 2 out of 3 short answer questions (40%) Chapter 6 Eyewitness Testimony Outline Independent and dependent eyewitness variables Recall and recognition information Line-up procedures and possible biases Expert testimony on eyewitness issues Recommendations for collecting eyewitness evidence Memory The stages of memory Encoding Stage Short-term Memory Stage Long-term Memory Stage Retrieval Stage Memory Not all information will go through all the memory stages There are factors that can affect each stage Memory can change each time we retrieve the event Memory types Recall Memory Reporting details of a previously witnessed event or person Recognition Memory Determining whether a previously seen item or person is the same as what is currently being viewed How do we study eyewitness issues? Archival data Naturalistic environments Laboratory simulations The most commonly used method The laboratory simulation Unknowing participant views a critical event The participant is then asked to describe what happened and the culprit involved They may be asked to view a lineup Many independent variables may be manipulated but only three general dependent variables in eyewitness studies Independent variables Estimator variables Variables or factors that are present at the time of the crime and that cannot be changed System variables Variables or factors that can be manipulated to increase (or decrease) eyewitness accuracy Both estimator and system variables can be manipulated in a laboratory study Dependent variables Three types in eyewitness studies Recall of the event/crime Recall of the culprit Recognition of the culprit Recall Open-ended recall (Free narrative) Witness either writes or orally states all they remember without any officer (or experimenter) questions Direct question recall Witness is asked a series of specific questions about the crime or the culprit Recognition Typical recognition task is the lineup Lineup A set of people presented to the witness, who in turn must identify the culprit if he or she is present Can be examined by: Accuracy of decision Types of errors made Interviewing eyewitnesses Primary goal of eyewitness interviews is to get a complete and accurate report of what happened Insufficient information may provide an officer with few leads Inaccurate information may lead to officers pursuing innocent suspects Interviewing eyewitnesses Standard Police Interview (Snook says “old school”) Officers introduce themselves Witness asked for open-ended recall of event Witness asked direct questions to determine specific information End interview by asking witness if there is any further information they can recall Interviewing eyewitnesses Police officers may limit their ability to collect information by: Interrupting eyewitnesses during open-ended recall Questioning eyewitnesses with very short, specific questions Asking questions in a predetermined or random order that may be inconsistent with the information being provided Watch Carefully… You are the witness! How fast was the Range Rover going when it hit the car? How badly was the man getting out of the tow truck hurt? The misinformation effect A witness’ recall report can be altered by the phrasing of a question Witnesses who are presented with inaccurate information after an event may incorporate that information in a subsequent recall task Explaining the misinformation effect Misinformation acceptance hypothesis Providing the answer the experimenter “wants” Source misattribution hypothesis Choosing the inaccurate memory even when the accurate memory is still accessible Memory impairment hypothesis The original memory is replaced with the new inaccurate memory How can the misinformation effect occur in real life? Officers may make assumptions and phrase questions to be consistent with this assumption Witnesses may overheard each others statements Police officers may incorporate inaccurate details from a previous witness’ interview into future questions Procedures that help police interview eyewitnesses? Hypnosis Cognitive interviews Enhanced cognitive interviews Hypnosis Hypnotically refreshed memory A hypnotized witness may be able to produce a greater number of details than a nonhypnotized witness ~10% of the population cannot be hypnotized; ~5% - 10% are highly suggestible Details provided under hypnosis are just as likely to be inaccurate as accurate Information obtained under hypnosis is not usually admissible in court Cognitive interviews Based on 4 memory retrieval techniques Reinstating the context Reporting everything Reversing order Changing perspective Enhanced cognitive interviews Expanded cognitive interview including various principles of social dynamics Additional components Rapport building Supportive interviewer behaviour Transfer of control Focused retrieval Witness-compatible questioning Recall of the culprit Witnesses are asked to describe the culprit’s appearance But these descriptions are often vague and apply to many people Quantity and accuracy of descriptions Descriptions are limited in detail and accuracy Hair, clothing, sex and height are commonly reported descriptors Recall following a long delay Memory repression Childhood sexual abuse memories are so traumatic that they are repressed into the subconcious Only as adults, through therapy, is the abuse recalled – Recovered memories False memory syndrome A therapy client’s false belief that they were sexually abused as a child Only through therapy and suggestive techniques do clients come to believe that they were abused when they were not Can traumatic memories be forgotten? Not having any memory is different from preferring not to think about it Criteria to consider when trying to determine if recovered memories are true Age of complainant at the time of the alleged abuse Techniques used to recover memory Similarity of reports across interview sessions Motivation for recall Time elapsed since the alleged abuse Recognition Can be assessed by: Live lineups or photo arrays Video surveillance records Voice identification Lineups Witness views a group of possible suspects and determines if one is the culprit Helps reduce uncertainty about whether the suspect is the culprit Lineup distractors Foils (distractors) People known to be innocent of the crime Similarity-to-suspect Matches lineup members to the suspect’s appearance Match-to-description Foils matched only on the items that the witness provided in their description Fair lineup One in which the suspect does not stand out from the other lineup members Estimating identification accuracy Target-present lineup The culprit is present in the lineup Target-absent lineup The culprit is not present in the lineup Type of Identification decision lineup Correct False Foil Correct False identification rejection identification rejection identification Target- X X X Not possible Not possible present Target- Not possible Not possible X X X absent Identification decision implications Correct decisions Identify culprit in target-present Rejection in target-absent Incorrect decisions Foil identification False rejection False identification Live lineups or photo arrays? Photo arrays used more often than live lineup Less time consuming to construct Portable – can be taken anywhere Suspect does not have the right to council as with live lineup Static – suspects behaviour may draw attention in live lineups Witness may be less anxious examining a photo array Another alternative is videotaped lineups Lineup presentation procedures Simultaneous lineup Present all lineup members at once Encourages witness to make a relative judgment by comparing lineup members Sequential lineup Present lineup members one at a time Must decide if it is the culprit before seeing the next lineup member Encourages absolute judgment where each lineup member is compared to the witness’ memory Lineup presentation procedures Showup Shows only one person, the suspect Used for deathbed confessions or if the suspect is apprehended immediately at or near the crime Walk-by Occurs in a naturalistic environment Public location where suspect is likely to be, when suspect is in view the witness is asked if they see the culprit Lineup biases Biased lineups Suggest who the police suspect and thereby who the witness should identify Suspect stands out from other lineup members False positives may be increased by: Foil bias Clothing bias Instruction bias Biased Lineup Unbiased Lineup Identify the bomber Identification from surveillance recordings It must be easier to identify the culprit when he or she is caught on camera, right? Many factors affect identification from video recordings Lighting View Disguise Who was in the video? Voice identification Factors that increase voice identification: Length of the voice sample Non-distinctive voices Viewing the culprit’s face when the incident was witnessed Factors that decrease voice identification: Whispering Placing the culprit voice near the end of the lineup A large number of foils Estimator variables Age No differences in accuracy for target-present lineup Older adults more likely to make incorrect decision from a target-absent lineup Older adults have more difficulty making correct rejections Estimator variables Cross-race effect Witnesses remembering faces of people of their own race with greater accuracy than faces of people of other races May be explained by: Attitudes Physiognomic homogeneity Interracial contact Estimator variables Weapon focus Witness’ attention being focused on the culprit’s weapon rather than on the culprit May be explained by: Arousal (cue-utilization hypothesis) Unusualness Are confident witnesses accurate? Neil v. Biggers 1972 The confidence of a witness should be taken as an indicator of accuracy Small positive correlation does exist But this relationship can be manipulated Expert testimony on eyewitness issues May be able to help the courts with decision making Controversial because of: The applicability of laboratory results to real world cases The reliability of results Common sense nature of research findings Public policy issues and guidelines Public misunderstands eyewitness testimony Overestimate identification accuracy Do not understand the influence of situational factors on identification accuracy Are not aware of system variables that may lead to increases (or decreases) in identification accuracy Guidelines for eyewitness testimony The person who conducts the lineup or photo array should not know which person is the suspect Eyewitnesses should be told explicitly that the criminal may not be present in the lineup Guidelines for eyewitness testimony The suspect should not stand out in the lineup as being different from the foils based on the eyewitnesses description or other factors A clear statement should be taken from the eyewitness at the time of the identification as to his or her confidence Lineup procedures should be videotaped Canadian guidelines Lineup procedure should be videotaped or audiotaped Officers should inform witnesses that it is just as important to clear innocent suspects as it is to identify guilty suspects The photo lineup should be presented sequentially Officers should not discuss a witness’ identification decision with him or her Evaluation Overall, how did you find this lecture? What was the best part of this lecture? What do you think needed improvement? Thank you!