- Created by: SarahD95
- Created on: 11-05-14 12:00
Frowd et al - Recognising Facial features
Aim: to investigate whihc is more recognisable internal or external facial features
Method/Design: 3 lab exps (Stirling uni), independent measures design
Participants: EXP1 - 30 staff/students from stirign uni 15M&5F, 18-60, £2 to sort 40 composites of 10 celeb photos using E-FIT, EXP2 - 48 undergrad students, 21M&27F, pick celeb faces that match composites shown
Results: EXP1 matched external features & whole faces correctly 33% of time and 19.5% with internal features. EXP2 external features mastched correctly 42% more easily than internal features 24% of time this was consistent across difficult and easy types.
Conclusion: EXP1&2 performed just above chance with internal features and did equally well with external and whole faces, which suggests that even with recogniasable faces like celebs it is hard to reconsrtuct the internal feactures
Loftus et al - Weapon focus
Aim: provide support for the 'weapon focus' effect when wrestling a crime
Method/Design: lab exp
Participants: 36 students Washington uni, aged 18-31, 1/2 recruited through ad $3.50, 1/2 exchange for psych credit
Procedure: control ps shown slides of people in Taco Bell line, person B hands cahier a cheque
Exp ps shown same slides as the control but person B pulls a gun instead
Ps filled a multichoice , 20 item Q and pick person B out of 12 head-shoulder photos and rate confidence on their choice ona scale of 1-6
Results: Questionnaires showed no signif diff bewteen the 2 conditions. Control ps chose correctly 38.9% of time whereas weapon condition chose correctly 1.11% of time. No differecen in confidence of the ps across the conditions and eye fixation data showed an average of 3.72 on the gun and 2.44% on the cheque
Conclusion: ps spent longer looking at the weapon therefore had more diffculty indentifying the suspect. The influence may be greater in reality when a wirness would be more aroused
Fisher - Cognitive interview technique
Aim: to test the cognitive interview (CI) in the field
Method/Design: field exp, actual interviews of real witness by serving police dectives
Participants:16 detectives robbery division of Dade County Florida, at least 5 years experience
Procedure: ps were asked to record a selection of their next interviews using the standard interview technique as normal. Ps were divided into 2 groups, G1 trained on CI & G2 used stantard technique. G1 - 4, 60min training sessions, 7 detectives completed the program, next 7m more interviews were recorded by both groups. Post training interviews analysed by a blind team at uni in California
Results: the CI trained detectives collected 47% monre info than before and 63% more than the untrained detectives. No diff in accuracy across conditions and CI took longer.
Conclusion: string support wsa gethered for CI as more info was collected with no loss of accuracy and only a little time increase
Mann - Detecting true lies
Aim: to test police officers ability to distinguish truths & lies during police interviews with suspects
Method/Design: field exp (police station)
Participants: 99 kent police offciers 24F and 75M av age 34.3
Judge truthfulness in rl police interviews shown 54 clips & filled a Q about their experience in detecting lies, after each clip, they indicated whether telling truth/lie and rate confidence
Results: no signif diff between lie and truth accuracy but both were signif above chance (50&). Experience in interviewing was correlated with truth and lie accuracy. Most frequently mentioned cues were gaze , movements, vagueness, contradictions in stories and fidgeting.
Conclusion: the more experience an officer has th better they are at detecting lies. Good lie dectors rely more on story cues than body language.
Inbau - Criminal interrogation & confessions
9 step inerrogation technique
1. Direct confrontation
2. offer the suspect the opp to shift blame on to another or explanantion
3. Suspect should never be allowed to deny guilt. Interupt suspect if they attemp to deny guilt
4. Ignore denials, suspect will often try to give reason why they could not have done the crime
5. Reinforce sincerity by staying close, keeping good eye contact, use first names
6. suspect eventually becomes quieter, if suspect cries infer guilt
7. give 2 choices, 1 is more socially acceptable, but whatever tehy chooes they admit to guilt
8. Get the suspect to admit guilt in front of witness
9. Document their confession and get them to sign to avoid them retracting later
Inbau thout theuse of this technique was justified because it was used on people who were deemed suspects through their prelimary interview but it has been found that using this technique on young or mentally impaired people can lead to false confessions.
Gudjohnsson - False confessions
Aim: to doc a case of the FC of a youth who was distressed & under interrogative pressure
Method/Design: case study, single subject design
Participants: (FC) 17 yo boy, av intelligance, no mental personality was not obvs abnormal
- 1987 2 elderly women found dead in their homes, savings were missing & sexual assualted
- FC was arrested because of inconsistencies in accounts of movements during an early enquiry
- Also, he was spending more money than usual however forensic evidence to link him to the case
- During the interview he was accuesed repeatedly of lying
- Q were leading and accusatory, police also suggested sexual impotency
- He found this very distressing and after 14 hours of aggressivs questioning he confessed
- Took back his confession the next day
- Confessed aging under pressure about inability to have good relationships with women
- after a year in jail he was released when another person pleaed guilty to the crime
Conclusion: this is a clear case of 'coerced compliance'. He felt pressurised and confessed to escape the situation.
Hazelwood - Lust murderer (organised/disorganised)
36 convosted sexually orientated murders including Ted Bundy & Chase Mason
Crime scene can be used in the same way as fingerprints to help identify the murderer
- Orderly life
- Kills after to going to some sort of critical event
- Actions reflect planning, order, control (restraints, bring weapon to crime scene)
- Offender is more likely to use verbal approach with victims
- Average-high inteligance & socially competent
- More likely to be employed
- Crime - moment of passion - no pre planning
- Using whatever is to hand as weapon
- May leave blood, semen, fingerprints, murder weapon
- Less intelligent & socially imcompetent
- Most likely unemployed
Canter - Top-down approach (USA)
Aim: to test the realiability of organised/disorganised typology
Procedure: 100 cases were assesd to fins out if the features hypothesised to belong to each typology would be concictently and distinctively different.
- All cases were from USA, 3rd crime commited by each serial killler, analysed using The Crime Classification Manual to classify crimes as organised/disorganised based on replies to interviews.
Results: twice as many disorganised as organised crime scenes identified (suggest disorg is more common/easier to identify).
- 70% of cases body was concealed and in 75% sexual activity occured
- Further analysis failed to reveal any signif diff bewteen the 2 (org/disorg)
Conclusion: instead of there being a distinction between the 2 types of serial murder, all crimes had to have an organised element to them as they hadnt been caught after 3 killings
- Personality variables would be a better factor to research (individual differences)
Canter & Heritage - Bottom-up approach (UK)
Aim: to identify behaviour pattern from similarities bewteen offenders
Method/Design: content analysis of 66 sexual offences committed by 27 sex offenders was conducted to find 33 offence variables taht were clearly linked to potenial behaviour characteristics
The data was subjected to smallest space analysis
Results: central behaviours included - vaginal intercourse, no reaction with victim, impersonal language, suprise attack and victims clothes were dicturbed.
Less central behaviours included - attempted intimacy with victim, sexual behaviour, overt violence and agression, impersonal interaction and criminal behaviour and intent.
Conclucion: All 5 factors have been shown to contribute to all sexual offences but in different patterns for different individuals, therefore can lead to understanding how an offenders behaviour changes over time or whether 2 or more offences were committed by the same person. This is known as Canter's 5 factor theory.
Canter - Case study (John Duffy)
John Duffy was a serial ****** and killer, who in 2000, confessed to committing 25 offences bewteen 1975 and 1986. His victims were always women aged 15-32 and tageted near railway stations in and aroiund london.
Canter got involved in the early 80s and based his profile on the locations of the crimes and the evidence of Duffy's behaviour. According to his profile Duffy was a marauder who committed crimes near his home.
Preliminary profile: Canter suggested the suspect would:
- Live in Kilburn
- Married, no children - Has marriage problems
- Had few friends
- Martial arts/body builder
- Physically small (5'4"), unnatractive, right handed
- Needs to dominate women
- Fantasies of ****/*******
2000 people on suspect list, JD was about 1505 went to #1 as he matched the profile acurately