Witness appeal


penrod and cutler


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  • Created by: Amy Leech
  • Created on: 28-03-13 22:21

Castellow; The effects of physical attractiveness

Background:  Research has confirmed that physically attractive D's are treated more leniently by mock jurors than unattractive D's. The 'halo' effect and Dion's 'what is beautiful is good' also suggest we are biased towards perceiving attractive individuals in a positive way.

Aim: To investigate 1. whether an attractive D is less likely to be found guilty than an unnattractive D and 2. whether an attractive witness means a D is more likely to be found guilty.

Sample: 71 male and 74 female undergraduates on an introductory psychology course.

Method: A lab experiment using an independant measures design. In a mock trial format, based on sexual harassment case. Participants read the case, which was accompanied by photos of both D and plaintive. Photos used had been rated independently by a large sample on a 9point scale and the lowest (least attractive) and the highest ( most attractive) scoring photos were selected. IVs: 1.gender of participant; 2. D's attractiveness, 3. Plaintiff's attractiveness. Main DV was participants verdicts (i.e. not guilty/guilty); also asked to rate D and plaintiff on 11point bi-polar adjective scales (e.g. dull, exciting).

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Castellow; The effects of physical attractiveness

Results: Attractive defendants were given fewer guilty verdicts (71%) than unnattractive (83%) with an attractive plaintiff, and 41% compared to 69% guilty verdicts with an unattractive plaintiff. On 11 measures of personal characteristics, both males and females rated the attractive defendant more positively than the unattractive defendant on all variables. 

Evaluation: Independent rating of photos eliminates researcher bias. Determinism - attractiveness wil vary with cultural ideals. Not very useful, however essential to identify factors which might bias jurors and possibly lead to miscarriages of justice. 

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Penrod and Cutler; The effect of witness confidenc

Background: Jurors seem to be highly influenced by witness confidence, perhaps believing that a confident witness is more likely to be accurate/reliable.

Aim: To identify juror sensitivity to witness confidence and other factors. 

Sample: Undergraduates and eligible and experienced jurors.

Method: Participants watched a videotape. 10 variables (IVs) were manipulated (with 'high' and 'low' conditions) e.g. disguise ('high': suspect heavily disguised; 'low': suspect minimally disguised); weapon focus ('high': weapon clearly brandished; 'low' :weapon visible); witness confidence ('high': expressed 100% confidence in identification; 'low' expressed 80% confidence). DVs: jurors' verdicts.

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Penrod and Cutler; The effect of witness confidenc

Results: Percentage of guilty verdicts for disguise and weapon focus resulted in 63-64% whether high or low (not significant; neither were the other seven variables). Witness confidence (about identification) was the only statistically significant result with 100% confidence expressed by witness resulting in 67% guilty verdicts, compared to 60% guilty verdicts given when 80% confidence expressed by witness.

Evaluation: In 9 other studies reported here, testing the relationship between identification accuracy and pre-identification confidence in ability to make an identitification, the confidence - accuracy correlation ranged from 0.00 to 0.20, i.e no correlation - very weka correlation. In other words, confidence in ability is not related to accuracy in identification. The useof eligible and experienced jurors as part of the sample strenghtens reliablity only marginally. Determinism (social) witness confidence. It is imperative that jurors critically examine all evidence and are not swayed by witness confidence, to prevent miscarriages of justice.

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Ross; The impact of protective shields/videotaped

Background: Protective devices for child eyewitnessess are used to reduce psychological stress: however, there is concern about whether their use is prejudicial i.e. implies guilt (credibility deflation) of defendant/believability of witness (credibility inflation).

Aim: 1. To investigate the impact of protective shields/videotaped evidence on guilty verdicts. 2. To investigate if protective devices result in crediblity inflation or deflation.

Sample: 300 introductory psychology students(gender balanced); the majority were white and middle class.

Method: A lab experiment using an independant measures design. Participants assigned equsally to three conditions (IVs): child testimony given in 1) open court (in full view); 2) behind (4x6 ft) screen; 3) via video-link. Participants watched (one of 3 versionss) of a 2 hour, trial simualation based on a real case, filmed by a professional crew in a real courtroom, with actors role-playing a child sexual abuse case. DVs: 1 Verdicts (guilty/not guilty); 2. Credibility rating of D; and 3. Credibility rating of witnessss. Two real attorneys gave advice to ensure trial was ecologically valid in terms of legal procedure.

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Ross; The impact of protective shields/videotaped

Results: No significant differences in guilty verdicts were found between the three conditions; however; females gave more guilty verdicts, 59% than males, 39%. No significant differences in the three conditions regarding the jury's perception if the D's credibility, but females rated the D less credible than males (consistent with their guilty verdicts). There were no significant differences found across three conditions reagrding the crediblity of the witness; however; female students rated the child as more credible (consistent with their guilty verdicts). A second experiment using 60 student participants, followed essentially the same procedures, although in addition it manipulated warnings given to the jury about the use of shields/videotapes. The film was stopped and measures were takena fter the child had given evidence; this is not the procedure followed in the real courtroom.

Evaluation: Large samples are more reliable, although student samples are atypical/unrepresentative. Mock trials and lab experiments, where decisions have no consequences, are low in ecological validity and therefore we have to be very careful in applying/generalising the findings. No evidence of social determinism/situational explanations of behaviour from these courtroom procedures. Not very useful however to ensure no miscarriages of justice it is very useful to know courtroom procedures do not bias the judicial process.

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