Final answer:
The defense may claim that six-year-old Shirley's testimony could be invalid because her memories are highly susceptible to suggestion. Research by cognitive psychologists like Elizabeth Loftus substantiates concerns over the fragility and suggestibility of children's memories, particularly when influenced by leading questions or external information.
Step-by-step explanation:
The testimony of six-year-old Shirley could be argued as invalid on the grounds that her memories may be susceptible to suggestion. Cognitive psychologists, such as Elizabeth Loftus, have demonstrated through research that children's memories can be heavily influenced by external suggestions. This phenomenon is known as the misinformation effect, where subsequent information can alter a person's recall of an event. For instance, studies by Stephen Ceci and Maggie Brucks revealed that young children can be prompted to indicate incorrect details when using anatomically correct dolls, demonstrating a high susceptibility to suggestion.
The integrity of eyewitness testimony, especially from children, must be maintained through careful interviewing techniques. To reduce suggestibility, interviewers are encouraged to use neutral and less leading questions, which allows children to more accurately recall events. Modifications to police lineup procedures, such as implementing a blind photo lineup, have been recommended to prevent leading cues that may influence witnesses. Moreover, the judiciary may inform jurors on the potential for misidentification and suppress unreliable eyewitness evidence.