Eye Witness Testimony

Lecture 2

EWT recap Researchers relate general memory research to EWT Information processing model - used as method for organising and understanding factors which may influence reliability of information obtained from a witness

Acquisition stage – witnessing/ involvement in incident

Retention stage – waiting period prior to giving evidence

Retrieval stage – giving evidence Memory can be affected at each stage by a range of variables

Variables affecting eyewitness testimony and identification (from Hollin 1989: 154)

Social Situational Individual Interrogational

AttitudesConformity PrejudiceStereotyping Status of interrogator

Complexity of event Duration of event Illumination- time of dayTime delay Type of crime

AgeCognitive style Personality EthnicityGender Training

Artists sketchComputer systemsID paradesMugshotsPhotofits

Estimator vs System variables (Wells, 1978) Estimator variables

Factors which cannot be controlled by the criminal justice system (and can only be estimated).

E.g. the length of time the witness saw the culprit

System variables

Factors that are under the control of the criminal justice system (hence system)

E.g. the way a line -up is conducted

N.B. These are not two discrete categories

Estimator variablesEstimator variables

Stable witness factors Malleable witness factors Confidence & effect of feedback (Feedback

system variable ) Target characteristics Event conditions Post event factors

System variablesSystem variables

Questioning Instruction bias Presentation bias Content bias Investigator bias Culprit present/absent

Estimator variables Witness characteristics

Age - consistently linked to performance ( Wells & Olson, 2003)

Memory suggested to deteriorate Older adults find it more difficult to divide attention

Lower quantity and quality of recall Somewhat lower rates of correct IDs

When line up contains culprit perform nearly as well as young adults

In target absent line ups make more mistaken IDs 25-50% in some studies ( Pozzulo & Lindsay, 1998)

Children as Witnesses

Until recently British courts have not placed much weight on children’s testimony

Was rare to accept evidence from children under 8

And even older children’s evidence needed corroboration

Furthermore judges were required to warn juries that it was dangerous to convict the accused on the basis of a child’s evidence alone (‘judicial caution’)

Spencer (1987) called this ‘a child molester’s charter’

Children as witnesses

Memory ability does improve with age – younger children recall less information than older children (eg Clifford, 1993).

However this does not mean that young children’s testimony is inaccurate (eg Fivush, 1993)

Proportion of correct information not different from adults

Children more likely to choose during ID Leads increase in false ID especially in target absent lineups

Children as witnesses

Children suggested to be more susceptible to suggestive questioning / misinformation – younger more likely to be affected

However all memory prone to distortion by suggestion – the question is whether this tendency is significantly greater in children

Typical studies involve a staged incident followed by questions at a later date. Some of the questions are designed to mislead. (eg Ceci et al )

Problems – Deliberate attempts to mislead – would this happen in real life?

Events not unpleasant or memorable (for ethical reasons)

Children as witnesses

Fivush & Scharzmueller (1998) – 4 year olds could recall distinctive events when they were 2

‘it is now accepted that children are capable of producing competent accounts of incidents, provided that they are questioned in an appropriate manner’ ( Ainsworth 1998: 130)

Conclusion – it is not necessarily the age of the child but the way that they are interviewed that is important

Gender Males and females suggested to take in different aspects of an event

Females remember more detail ( Powers et al. 1979)

Females may make more correct identifications but may also make mistaken identifications – more likely to attempt an identification

Overall little differences However females better at identifying female faces than male faces

Ethnicity No evidence that specific ethnic groups perform better than others

25 years of research concludes that

Better at recognising people from own ethnic group (Meisser & Brigham 2001)

Irrespective of age of witness Only small relationship with familiarity of other groups

Cross race effect

Occupation and intelligence

Assumption that certain groups better than others e.g. police v lay people

Research has found no differences in accuracy ( Malpass et al, 2005 )

Police gave better quality descriptions of criminal event

Suggested that those with lower IQ perform in similar manner to very young and old

Confidence Assumption that a more confident witness is more accurate

Much research found only small correlation between confidence and accuracy

Malleable nature of confidence – influenced by feedback about performance

Interaction with personality

Effect of alcohol Effect on memory generally extensively researched and recently applied to eyewitnesses

Alters perceptual processes Influences ability to encode and store information

Interferes with formation of long term memories

Highly intoxicated decrease in recall and accuracy

More prone to making a false ID

Event characteristics

Length exposure – longer period better recall However no optimal time identified – need to take into account attention and interest

Distance from offence Position of witness in relationship to event Illumination of scene Less complete statements when incident took place at twilight as opposed to either day or night ( Kuehn, 1974)

Daylight best ( Yarmey 1986b)

Event characteristics stress and fear

Many studies – but ethical problems in lab. situations so only mild stress induced usually

Yerkes- Dobson Law suggests very low and very high levels arousal negative impact on encoding information

However meta analysis ( Deffenbacher et al, 2004)

Mild stress - diverts attention to event Higher levels - produce increase in memory performance

Extreme stress - dramatic decline in performance Applicable to victim witnesses Weapon focus phenomena ( Loftus et al, 1987) Causes narrowing of attention – loss of peripheral details being recorded

Event characteristics Type of attention given Importance attached to crime ( Leippe et al, 1978)

More likely to be able to identify if crime serious ( Ibid)

Issue – observers may not realise they are witnessing a crime until after culprit fled

May have seen them for while but not paid much attention if they were not behaving in significantly unusual manner

Target characteristics Distinctiveness appearance/ facial features Distinctive faces more likely to be recognised than non distinctive

Either highly unattractive or highly attractive more easily recognised ( Fleishman et al, 1976)

Women more easily recognised than men – hair ? Faces perceived as criminal falsely identified at ID

Simple disguises- even as simple as covering the hair result in significant impairment of eyewitness

Sunglasses although if targets wore sunglasses at time of recognition test this reduced ( Hockley et al, 1999)

Post event information

If multiple witnesses present They may well confer and attempt to reach a consensus about the crime/perpetrator

Any new information (from the press, other witnesses) can change original memory

Once this new memory has been incorporated it is difficult to remove

System variables

Questioning – next weeks lecture looks at interviewing witnesses

Instructions/ feedback Content Presentation method Behavioural influences Investigator bias

Interviewing Multiple descriptions – if interviewed on few occasions tend to give more information – phenomenon called hypermnesia

Repeated testing / questioning inflates sense of accuracy (Shaw, 1996)

repeated interviewing can also contaminate memory

Repeating same information Forgetting other information Also if incorrect information introduced by witness this can then become integrated into the account

Interviewing Misinformation effects Investigator may convey new information which then becomes incorporated into the witness’ account

Loftus ( 1996) witnesses watched simulated crime

Half witnesses receive misleading information about event

Then all witnesses attempt to recall original information

Those who had not received misleading information more accurate

Scores studies shown this effect Also leading questions

Identification stage Accuracy decreases if witness gives verbal description just prior to making an ID (verbal overshadowing effect)

‘Refreshing’ witnesses memory by this method may result in false ID

Use of mug shots Can result in source monitoring error Can wrongly identify suspect as being at scene of crime

Instead of just in mug shot Important then to determine if mug -shots been employed

Identification stageComposites Witness constructs likeness via computer programme

Shown to produce poor likenesses Can also contaminate memory If composite picture appears in press also problematic

Repeated viewing of composite contaminates memory

If suspect arrested on basis of composite Important to find out how generated and how often witness viewed it

Identification stage Line ups Either live or series photographs Research suggests no difference in accuracy rates ( Malpass et al, 2005)

America Technical Working group on Eyewitness Evidence (1999)

Suggest range of procedures to minimise mistakes

Relating to line up method Use of fillers Pre - line up instructions

System variables: Line up content Fillers – innocent line up members -should be a minimum of 5

Need to ensure that innocent person not chosen because they stand out in someway – same ethnic group as suspect etc

Also that suspect is not correctly identified because they blend in too much

Better to select fillers who resemble verbal descriptions of culprit

System variables: Line up content

Consistency of appearance – distinguishing features eg tatoos should be concealed or added to fillers

When showing a new suspect same fillers should not be used

If perpetrator wore a disguise These can be added to photo However issues – witness just identifying the disguise?

Culprit present/ absent Line may or may not include actual culprit eg if an innocent person the suspect

When culprit present in mock 6 person line up 54% made correct identification 21% no identification

When culprit removed without replacement 32% made no identification 68% identified someone who was not the suspect ( Wells 1993)

People use relative judgement effect Select person from line up who most closely matches memory of culprit

Ok when culprit present Not so good when culprit absent

System variables: line up Instructions Pre line up instructions to witnesses repeatedly shown to have impact on testimonies ( Steblay 1997)

If told culprit is present in line up considerably more mistaken identifications

If only told they may or may not be present mistaken identifications reduced by 41.6%

Only minimal reduction in accuracy rates

System variables: line up Line up presentation method Sequential v simultaneous presentation

Simultaneous – shown whole line up at once Relative judgement effect problematic

Sequential – one line up member shown at a time

Eyewitness required to make a decision before next member seen

Best results in terms of accuracy if participant does not know how many ‘suspects’ they will see

System variables: line up Reduces relative judgement effect - Each ‘suspect’ tends to be compared to memory

Sequential Shown to reduce the chances of mistaken identity in culprit absent line ups by nearly 50% ( Stelbay et al 2001)

However also associated with reduction in accurate line ups when culprit present

System variables: communication

Behaviour of person conducting line up - can communicate knowledge about who is suspect by verbal and non verbal signals ( Philips et al 1999)

Post identification suggestions shown to lead mistaken witnesses to develop high levels of false certainty (Wells & Bradfield, 1999)

Eyewitnesses who had made mistaken identifications Some given positive feedback Others no feedback

Those given positive feed back suggested they were more certain about the identity suspect than group given no feedback

Greater for those who make a mistaken identification than for those who make an accurate identification ( Bradfield et al, 2002)

Problems with eye witness research

Stephenson (1988) argues that most of the research into eyewitness reliability is flawed because it is artificial

Wells and Olson (2003) point out that the laboratory studies reveal serious potential flaws in eyewitness testimony but that this should be supplemented with research into real cases

These may reveal differences to the lab based research and new variables not yet considered by researchers

Cohen (1986) believes that research tends to look for the mistakes that eyewitnesses make and therefore presents a distorted view.

References Cattell, J.M. (1895). Measurements of the accuracy of

recollection. Science , 2 : 761-766.Crombag, H.F.M. Wagenaar, W.A. & Van Kopen, P.J.

(1996). Crashing memories and the problem of source monitoring.

Applied Cognitive Psychology, 10: 95-104.Freud, S. 91906) Psychoanalysis and the ascertaining of

truth in courts of law.Collected Papers; vol. 2, New York, Basic

Books. Hollins, C.R. (1989) Psychology and Crime: An introduction to criminological psychology, London, Routledge.Howitt, D. (2006) Introduction to Criminal and Forensic Psychology (2nd Ed ). Harlow, Pearson Prentice Hall.King, M. (1986) Psychology in and out of Court, London,

Pergamon Press.

ReferencesLoftus, E.& Palmer, J.C. (1974) Reconstructions of automobile destruction: An example of the interaction between

language and memory. Journal of Verbal Learning and verbal Behavior, 13: 585-589.

Loftus, E. & Pickrell, J.E. (1995) the formation of false memories.

Psychiatric Annals, 25: 720-725.Memon, Vrij and Bull (2003). Psychology and Law (2nd Edition). WileyWeber, N. Brewer, N. & Wells, G. (2004b) Is there a ’magical’ decision latency that discriminates correct from incorrect eyewitness identifications? Paper presented at 14th

conference ofthe European Association of Psychology and Law, Krakow,

Poland. Wells and Olson (2003). Eyewitness Testimony. Annual Review of

Psychology, 54, 277-295

Websites http://eyewitness.utep.edu The homepage of the Eyewitness Identification Research Laboratory, University of Texas. (Good for information and some practical exercises on line ups.)

http://www.psychology.iastate.edu/faculty/gwells/homepage.htm

Prof. Gary Wells homepage. Access to many of his articles, news items and to video footage of eyewitness identification.