Why has the LAPD chosen to remain resistant to science-based eyewitness identification practices?

The title of an August 24 LA Times article says it all: “LAPD Reluctant to Change Its Handling of Photo Lineups.”  Having lineups conducted by someone other than the detective assigned to the case, who knows which photo shows the person they suspect, is backed by decades of science, but the LAPD opposes it.

The reason for having someone other than a person who knows the “right” answer administer the lineup is based on a well-established scientific protocol to avoid unconscious human bias.  Researchers long ago established that when the administrator of an experiment gives the subject choices from which to pick, the subject picks the right choice more often when the administrator knows which choice is the right answer.  This is called the experimenter-expectancy effect.  It is a form of cognitive bias, in which the person running the experiment who knows the preferred answer gives the subject making the choice subtle but unmistakable cues, without either intending to or realizing it.  To avoid this, scientists :”blind” the person administering the experiment and communicating with the subject.  The administrator therefore does not know the right answer, and therefore cannot communicate it.

Blind experiments are among the most basic requirements of science; we would never take an over-the-counter medicine if we knew that it hadn’t been tested this way.

And yet, with jurisdictions as different as New Jersey, Connecticut and Texas going with eyewitness procedures based on science, including blind lineup administration, LA Police Chief Charlie Beck continues to resist.  According to the Times,  Beck said “if you don’t adhere to the rules, either process is flawed. It’s more important to do them correctly than it is which process you use.”

No — wrong.  I’m an admirer of Chief Beck (and his predecessor, William Bratton), after seeing the transformation of the formerly-broken  LAPD into one of the better large police departments in the country.   But in this instance, Chief Beck is wrong.  What’s important is to move to a process that produces measurably fewer errors.  Sure, people can screw up anything by doing it wrong.  But the evidence is not in doubt: putting a person not involved in the case in charge of lineups eliminates bias — not because police are bad or unfair, but because they are human beings, subject to the same cognitive errors all  human beings are.


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