Graham Davies Week 4 Enhancing police interviewing of witnesses

Psychology and Police Interviewing Interviews with witnesses still remain the major source of information in solving crime Psychologists have been increasingly called upon to refine existing procedures for interviewing both suspects and witnesses Work on false confessions(Gudjonnson);hypnotic and cognitive interviews

Hypnotic Interview (Reiser, 1990) focussed attention (drawing pin) relaxation (imagery) distancing (TV screen) regression (context induction) suggestion (perfect recall)

Success – The LAPD Study (Reiser, 1980) 374 ‘dead’ cases witnesses re-interviewed under hypnosis 54% new information 16% cleared up

Reiser’s ‘Cybernetic’ Model of Memory All information is stored All is potentially available Hypnotic procedures have no impact on memories “The mind is like a videotape machine, everything is recorded, perhaps at a subconscious level and stored in the brain, but available under hypnosis” (Reiser, 1980)

Predictions of Cybernetic Model More complete recall under hypnosis Fewer errors Reduced impact of leading questions and post-event misinformation A facet of the wider debate as to whether hypnosis is an altered state of consciousness.

Research on Hypnosis and Memory No impact on lab tasks (Mingay, 1987; Erdelyi, 1992) Limited realism? (Yuille & McEwan, 1985) Confidence and leading questions (Putnam, 1979) But isolated positive findings, particularly with more realistic settings (Yuille & Kim, 1987)

Cognitive explanations for positive findings from hypnosis Impact of cognitive reinstatement instructions (Timm, 1981) Criterion shift (Dywan & Bowers, 1983) Hypermnesia (Cooper & London, 1973)

Social explanations for positive findings from hypnosis Compliance and belief (Wagstaff, 1999) Relaxation and surrendering control (Wagstaff, 1982)

Hypnosis: More than the sum of its parts ? High belief in hypnosis aiding memory (Orne, %) High impact on trial outcome (Wagstaff et al., 1992) People vs Kempinski (1980) False memory production (Orne, 1979)

The Backlash Hypnotic testimony now banned in 25 States People v. Shirley (1982) All three major organisations for hypnotists now ban use with witnesses

HOME OFFICE GUIDELINES (1988) Only qualified personnel Informed consent No investigators present Videotape of whole interview only when all other methods have failed the impact of R v Browning (1994)

The Cognitive Interview An approach to interviewing grounded in theories of memory function Simple ideas but widely taken up by the police world-wide Developed by Geiselman & Fisher (1984)

Theoretical Assumptions Memory as a bundle of features – retrieval involves feature overlap (Bower, 1967) Memories may be accessed via explicit but multiple pathways. Inappropriate cueing will lead to retrieval failure (Tulving, 1974)

Mnemonic techniques of the cognitive interview feature overlap induced by: - mental reconstruction of environmental/ personal context - report all details instruction retrieval paths exploited by: - recounting event in different orders - reporting events from a different perspective Plus explicit mnemonics (alphabet searching; resemblance to known person etc.)

CI vs ‘Standard’ Police interview and hypnosis (Geiselman et al. 1985) Police training film of violent crime Experienced police officers vs CI trained college student interviewers 40% increase in correct information and no effect on errors No difference between hypnotic and CI interviews.

The enhanced cognitive interview (Fisher & Geiselman, 1992) Much greater emphasis upon communication skills, less on memory Rapport building and interviewer support Witness-compatible questioning Focused retrieval (imagery) ‘Perspective change’ and ‘report all details’ de-emphasised

Field study on CI Effectiveness (Fisher et al. 1989) Tape recorded interviews by 7 detectives investigating crime ‘on the street’ Constant interruptions of witnesses Formulaic interviews Specific questions After training in the Enhanced CI Increase in information from 34 – 115% 94% of ascertainable facts corroborated

Later research emphasised the importance of appropriate controls Earlier studies flawed: number of accounts not controlled Importance of motivation and n questions But positive effects still present (Kohnken et al. 1994)

Criterion shift or improved accuracy ? Meta-analysis of published studies (Kohnken et al. 1999) 35% increase in correct information but only 18% increase in errors from a low base

Which components are the most important ? context reinstatement most reliable but least used by serving officers (Memon et al. 1995) children may have difficulties with some components (Saywitz et al. 1995) Reinstatement may be inadvisable in cases of trauma (Geiselman, 1995)