I (re)posted several links on UK research into eyewitness ID a couple of weeks ago. Although both present a number of caveat concerning bad practice to avoid, the UK ones had a few other pointers to avoid.
IMO, I could imagine several issues in the case of MS:
a. His 60-80% suspicion was based on how the man held the child while walking downwards.
b. His wife apparently agreed that Smithman was of a similar stature.
c. Smithman wasn't wearing glasses.
d. The child was of a similar age and general description (aside from whoever noticed that the sleeves were long).
e. Gerry had just been made arguido, with all the negative tabloid (and ill-informed broadcast) coverage leading up to that, including "full DNA match" in the boot, etc.
f. Amaral was apparently only intending to get Martin over. Martin may not have wondered why that may be.
g. Amaral also said that it wouldn't be a physical line-up, so what would he have been shown, if anything? A rerun of Gerry walking down the plane steps?
h. How could it possibly be double-blind?
i. Would Martin have been sufficiently aware of the significance of any wording in the statement taken? I.e., would the fact that his impression was based solely on the way the man carried the child... or would that have been fudged over?
j. What would the PJ instructions have been? Would the PJ, at that stage, to be able to avoid conveying a sense of expectation of a positive ID, or positive feedback?
k. Would the fact of travelling all the way over have any subconscious influence (a sense of accomplishment / not wasting his / PJ time)?
"a. His 60-80% suspicion was based on how the man held the child while walking downwards." Did Martin Smith see Smithman carrying a child down steps in PdL?
"b. His wife apparently agreed that Smithman was of a similar stature." Studies have shown that confirmation even if wrong boost confidence but not reliability.
"c. Smithman wasn't wearing glasses." OK what was the point?
"d. The child was of a similar age and general description (aside from whoever noticed that the sleeves were long)." So is Martin Smith adding up all his family's recollections and adding them to his own memory - reconstructed memory.
"e. Gerry had just been made arguido, with all the negative tabloid (and ill-informed broadcast) coverage leading up to that, including "full DNA match" in the boot, etc." A know factor in inaccurate identifications. Nodding at the suspect.
"f. Amaral was apparently only intending to get Martin over. Martin may not have wondered why that may be." Possible source of error.
"g. Amaral also said that it wouldn't be a physical line-up, so what would he have been shown, if anything? A rerun of Gerry walking down the plane steps?" Not relevant to the actual Smithman situation.
"j. What would the PJ instructions have been? Would the PJ, at that stage, to be able to avoid conveying a sense of expectation of a positive ID, or positive feedback? " Probably not.
"
"h. How could it possibly be double-blind?" Whatever they did to Gerry and could do with 5 others, Get some PJ not involved with the case to run the reconstruction.
"i. Would Martin have been sufficiently aware of the significance of any wording in the statement taken? I.e., would the fact that his impression was based solely on the way the man carried the child... or would that have been fudged over?" Who knows!
"k. Would the fact of travelling all the way over have any subconscious influence (a sense of accomplishment / not wasting his / PJ time)?" Could be a factor. There were studies that emphasised the importance and that result in errors.