The Power of Suggestion

“Objection, your Honor, the Defense is leading the witness.”

If you’ve watched TV courtroom dramas, you’ve heard this common expression. One lawyer is complaining that the other lawyer is asking leading questions; the questions suggest the answers the witness should give. As such, it unfairly taints the witness’ testimony.

As often happens, a recent courtroom drama made me wonder if there’s any science behind the objection. Perhaps not surprisingly, there is.

In Daniel Schacter’s book The Seven Sins of Memory, he describes the sin of suggestibility in which people are susceptible to incorporate incorrect or even misleading information into their memories. The information can come from a wide variety of external sources – reading descriptions from other people, watching videos, or listening to others – but people later misremember the source of the memories. The memories based on outside information seem just as real as those based on our own experiences.

The book summarizes a series of experiments in which participants viewed a simulated armed robbery, answered intentionally misleading questions about what happened during the robbery, and then later were asked to verify whether their memories of the event came from the video or the questionnaire. Even when participants initially knew they hadn’t remembered information from the video and that the information had been suggested by the questions, the participants believed the information was accurate and later claimed they remembered it from the video. A false memory had been created.

The power of suggestion does not just happen in the courtroom and is not always intentional. During an investigation, police officers interview an eyewitness multiple times, asking questions from many different angles in the hopes of jogging their memory. However, there is an inherent danger that some of these questions are suggestive of new information and the eyewitness might later misremember the source of the memory. Eyewitness testimony is inherently unreliable.

All of this makes me consider my own childhood memories. Research shows it’s relatively simple to implant false childhood memories. I wonder how many of my memories are based on the original event and how many are derived from repeated discussions with my parents over the years. Remembering the events together clearly strengthens the belief in my own memory but doesn’t necessarily increase the accuracy.

While I doubt my parents were intentionally “leading the witness,” human nature suggests they bring up the ones they remember the most fondly. Over time, these are the ones I am most likely to discuss around them. We have a collective shared memory.

The power of the suggestion means you can’t trust your own memory.