Ross et al, (1994) ‘The impact of protective shields and videotape testimony on conviction rates

Ross et al, (1994) ‘The impact of protective shields and videotape testimony on conviction rates


This is the third study we will be looking at from the ‘witness appeal’ section of ‘reaching a verdict’, as part of your OCR A2 Forensic Psychology course. It is further categorised into ‘Videotapes and Shields’

In cases where children are witnesses to a crime they may have to be interviewed and give testimony in court. The following study examines the rates of conviction when a child witness gives either testimony from behind a shield or by video link.

Such protective measures are intended to prevent the witness from any undue stress, however, it may have a negative impact upon the defendant as the jury may think the defendant is guilty from the witness having to be protected.

Credibility Inflation: when the child’s testimony is more believable, because they are not so distressed and can answer questions in a confident way.

Credibility Deflation: when the child’s testimony is seen as unreliable, because they are distant and needing special support.


Ross et al (1994) aimed: to find out if the use of protective shields and videotaped testimony increases the likelihood of a guilty verdict.

To investigate the effect that the use of protective devices has on jury reaction to testimony. Do they add to the child witness’s credibility or do they make the child seem even more fragile and unreliable?

Method and Design

An experiment using a mock trial based on an actual court transcript. A professional film crew recorded actors playing the roles in the case.

Three 2-hour films were created, which were completely identical apart from the manipulation of the IV:

  1. Control: with the child witness in full view.
  2. Screen condition: with the child witness behind a 4′ by 6′ screen.
  3. Video condition: where the child gave a evidence via a video link from another room.

300 college students. (150 male, 150 female) from an introductory psychology class, the majority were White and middle class. They were told it was a study of psychology and the law.

100 students were assigned to each condition.


Participants watched on of the three versions of the two hour film of a court case of alleged abuse, in which the child’s father was the defendant and the mother, two expert witnesses one for either side, with the child herself taking part as a witness. The alleged abuse was single touch while the father was giving the child a bath and the question whether it was innocent or sexual in nature. The judge in the case read a warning before either the screen or the video monitor was used, clearly directing the jury not to assume guilt by their use. After the case, the participants gave their verdicts and rated the credibility of the child witness on various aspects of her story. They also rated the defendant on his credibility.


Percentages refer to the percentage of convictions.

Control: 51%

Shield: 46%

Video: 49%

The findings show no significant difference across the the conditions Yes, a guilty verdict was slightly more common in open court and slightly less likely when the child was screened, but these differences are not statistically significant.

Ross et al (1994) then carried out a second set of experiments where the film was stopped as soon as the child finished giving their testimony – no further witnesses (the child was the first witness) no summing up arguments and no closing speech from the judge warning the jurors against putting too much faith in eyewitness testimony. This time the participants in the control condition were much more likely to return a guilty verdict.


These results suggest that protective shields and videotaped testimonies can be used for child witnesses in a way that does not prejudice the jury against the defendant, but it is important that these measures are used carefully. Consideration has to be given to the position of the child’s testimony in the order of the trial and jurors must be warned not to assume that techniques like screens or videotapes imply that defendant is either guilty or innocent.

Ross et al (1994) Evaluation

– Boredom effects – the participants may not have paid attention to all the video as it was rather long.

+ Validity – the videos were exactly the same apart from the manipulation of the independent variable.

– No qualitative data – therefore the conclusions have to be inferred by the researchers.

+ Usefulness – the results of this study suggest that shields and videos can be used without affecting the jury.

+ Quantitative Data – The quantitive data is easy to compare and analyse, which makes it easy to establish cause and effect through statistical significance.

Audio Podcast


Ross et al, (1994) ‘The impact of protective shields and videotape testimony on conviction rates


Further Reading

OCR A2 Psychology Student Unit Guide: Unit G543: Forensic Psychology (Student Unit Guides)


Article Name
Ross et al, (1994) 'The impact of protective shields and videotape testimony on conviction rates
This is the third study we will be looking at from the 'witness appeal' section of 'reaching a verdict', as part of your OCR A2 Forensic Psychology course. It is further categorised into 'Videotapes and Shields'