Also, feedback from other witnesses can also inflate witness's confidence in their selection. That's why it's so important for police to not comment on a witness's selection. By the same token, witnesses become less confident in their memory if it is not reinforced or it is discouraged. It would be better if the person who administers the eyewitness test does not know who the suspect is. This is referred to as blind testing of the witness.
Studies also show that jurors tend to over-believe eyewitnesses.
That's another reason why it's so important to inform jurors of what the reliabe interviewing techniques are so they can use their own judgment in determining whether to believe an eyewitness. I don't believe so. The law treats circumstantial and direct evidence the same. I think we have to be careful that jurors don't pile inference upon inference, labeling that circumstantial evidence. I think it is always preferable to have physical evidence to prove that a person committed a crime.