The dangerous power held by the interviewer

A recent episode of This American Life tells a fascinating and horrifying story of a murder confession gone wrong. The story is a reflection from the retired detective who seems to have sincerely believed the woman in question to be guilty. He realizes in his reflection that he was open to hearing what fit his theory and dismissed information or cues that didn’t support his theory (this is known as confirmation bias). This is a real concern for people doing user research who have preconceived notions about people, their behavior, their desired solutions, etc. One tactic is to develop greater self-awareness and learn to hear your own biases and assumptions.

Even more disturbing in this story is how the suspect began to provide details of the crime that supposedly only the person who committed the crime would know. In fact, this woman who would want to clear her name, responded to the questioning by shifting to please her interrogator, looking to provide the “right” answers. While the police didn’t realize it, she was picking up clues from the documents they were showing her and presenting them back as if it was her own knowledge. She wasn’t trying to confess, she was trying to succeed in answering the questions, even though it was significantly against her own interests. This is also a crucial concern for user researchers, where participants will want to please them and will work hard to figure out what “pleasing” looks like. The way you ask questions (e.g,. “Do you like doing it this way or would you rather have it happen automatically when you enter the store?”) has a tremendous influence in how they are answered.

The New York Times offers this summary

He tells about a woman who confessed to killing a man. She knew insider things like that the victim was wearing his wedding ring when he died, and that his credit card had been used at a People’s drugstore and a Chinese takeout place. Case closed.

A few weeks go by, and it turns out the woman has a strong alibi. Charges are dropped.

Years later, with the case still officially open, Detective Trainum went back to the file because he still suspected that the woman had gotten away with murder. He discovered that he and the other detectives accidentally videotaped the whole interrogation — not just the confession. That’s when he found out how an innocent person could know unreleased details of the killing.

At one point during the interrogation, they were trying to get her to admit to using the dead guy’s credit cards, and said, isn’t that your signature on these slips? And they showed them to her. So she read the name of the drugstore and the restaurant.

At another moment, they showed her the crime scene photos. In one, the left hand of the corpse was prominent. You could see the wedding ring.

So they had accidentally fed her all the incriminating details that she returned to them in the confession.


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