A criticism of research investigating EWT concerns individual differences of witnesses.
An eyewitness typically acquires information from two sources, from observing the event itself and from subsequent suggestions (misleading information). A number of studies (e.g. Schacter et al, 1991) have found that, compared to younger subjects, elderly people have difficulty remembering the source of their information, even though their memory for the information itself is unimpaired. As a result, they become more prone to the effect of misleading information when giving testimony.