Flawed science?
I think it is obvious that an "expert witness" or "pshycological expert" can be found to take any side of an issue in ANY case, and believe he is right.
The "battle of expert witness testimony" occurs everyday in the courtrooms.
The notion that police force people to pick someone out of a lineup because they WANT to close the case or they WANT to get a certain individual off the street is more like what you mentioned, where people watch too much TV/Movies where this happens.
The jury heard the evidence, made thier decision on that evidence (hopefully), and convicted on that evidence. If that is not consistent with their duty and the law, then I am misguided.
"Expert" testimony on technical matters is a whole 'nother ball of wax - nothing to do with what I'm talking about.
The reality is that a great deal of what juries believe comes from outside experiences; they've been lead to believe eyewitness testimony and eyewitness IDs are very reliable, and if you believe the witness is not lying, then their testimony is automatically correct.
The reality is, based on scientific study, and the history of these cases, is that there should be reasonable doubt about ALL eyewitness testimony. I'd have a hard time convicting someone when that was the only or almost the only evidence.
And the academic studies showing this aren't from "hired gun" expert witnesses - just scientists interested in studying human memory.
One famous demonstration done in large psychology lecture classes is the professor hiring an actor to come in and steal something (without telling the class beforehand.) The incident happens and the students are asked to write down what the actor was wearing, what happened, etc. When they're reviewed, everyone reports wildly different clothing, appearance, sequence of events, etc, with most of them being very wrong.
Another really interesting one is plane crashes - time and time again, eyewitnesses will report crashing aircraft being on fire, when they were not (and often there is a videotape clearly showing no fire on the aircraft.) It's apparently a phenomenon where the brain inserts a false memory to make sense of viewing a traumatic experience.