When children report about an event they can be highly accurate. But if they talk to other witnesses, children's testimony may become tainted. A doctoral thesis from the University of Gothenburg examines children's vulnerability to co-witness influence, and presents a new method that can help child witnesses to provide more detailed witness reports.
Emma Roos af Hjelmsäter's thesis is based on a series of studies where children aged 7-13 were interviewed regarding an event they had experienced two weeks earlier. Prior to the interviews, some of the children listened to a co-witness' account of the same event – an account which contained some misinformation. Although the children's reports were generally quite accurate, the results showed that the information provided by the co-witness influenced the children to make errors when they reported about the event.
'The children were influenced to add false information, that is, some of the things they reported had in fact never occurred. But they were also influenced to omit true details', says Roos af Hjelmsäter.
Legal consequences
Thus, the thesis shows that the children were influenced to make two types of memory error: addition of false details and omission of true details. Both these types of memory error may have serious legal consequences.
'If a witness reports false details the investigation may be led in the wrong direction, and ultimately this may even result in the wrong person being convicted. On the other hand, if a witness leaves out or falsely denies a correct detail, crucial aspects may be neglected, and the case might never reach closure', says Roos af Hjelmsäter.
Roos af Hjelmsäter points out that since eyewitness testimony is the most common type of evidence in criminal cases, it is important to study factors that may affect the reliability of eyewitness testimony. It is also important to consider what type of event and information the testimony concerns. Roos af Hjelmsäter studied different types of information and found large differences depending on the type of detail the children were asked about.
'Previous research has often concluded that children are both unreliable as witnesses and easy to influence. However, my thesis shows that when children report about central aspects of a personally experienced event, their reports can indeed be quite reliable', says Roos af Hjelmsäter.
Positive effects
One of the studies included in the thesis explored the effect of a "self-administered interview" (SAI), a questionnaire in which the children individually wrote down their memories soon after the event. The results showed that this helped children recall the event – when they were interviewed two weeks later, children who had previously used the SAI gave more detailed descriptions of the event.
'This is an important finding considering the fact that children tend to give sparse information while legal contexts often call for very detailed witness reports', says Roos af Hjelmsäter.