The memory of a fleeting glance is unreliable

In fact, a 1994 study found that up to 48% of witnesses tend to pick the wrong person out of a lineup,even when many are confident in their choice.Memory based on short glimpses can be unreliable,and we often overestimate our own accuracy.Knowing all this,a unanimous identification starts to seem less like certain guilt,and more like a systemic error,or bias in the lineup.And systemic errors don't just appear in matters of human judgement.