I recently watched Making a Murderer and I noticed that the story centers on some pretty interesting ideas in both law and psychology.

I'm not going to go into too much detail about the series, because spoilers, but in case you're not familiar with it, it's about a 2005 murder case in Wisconsin in the United States.

A man called Stephen Avery is accused of the murder, but what really struck a chord with me was the story of his nephew, Brendan Dassey.

Again I'll avoid details, but there are a few things I want to explore: False memories, incorrect eyewitness testimonies and false confessions.

These things cause most of the wrongful convictions in the criminal justice system.

And here's more about them, scientifically.

False Memories False memory is a phenomenon where you or recall an event differently from how it actually happened, or you remember something that never happened.

You may not realise it, but even you have false memories.

Your memory is mostly reconstructive, where you remember a general event or idea, but over time, you actively incorporate missing elements and details with wrong information.

And your memories are slightly modified every time you retrieve and reconsolidate them.

In some cases, fake memories have even been "planted" in people's' minds.

In a classic study, psychologists spoke to participants about real events from their childhood and then they introduced details of a false event; a time the participant became lost at the mall as a child.

about events from their participants childhood.

Later on, 25% of the participants recalled this false event as true, and some even fabricated details around the event that never happened.

Incorrect Eyewitness Testimonies Most false memories are nothing to worry about, but they can be a huge problem for criminal investigations if they lead people to give incorrect eyewitness testimonies or false confessions.

First of all, incorrect eyewitness identification is the leading cause of wrongful convictions in cases where DNA evidence later proved innocence.

A lot of errors are due to the Misinformation Effect, where memory becomes less accurate because new information interferes with the ability to retain the original memory.

In another classic study, participants saw a staged car accident at an intersection with a stop sign.

Then half the participants were asked a follow up question that referred to the stop sign as a "yield" or give way sign.

When later asked what sign it was, those given the suggestion were more likely to claim that they had seen a yield sign.

Incorrectly identifying people has a big impact too.

In 1982, police suspected Marvin Anderson was guilty of a sexual assault, so they obtained a colour photo of him and showed it to the victim along with half a dozen black and white mug shots of other people.

The victim chose the colour photo and identified him in a police lineup where he was the only person whose picture they had seen before.

Marvin was innocent, he even had an alibi, yet he was still convicted.

He served 15 years in prison before DNA testing proved his innocence.

False Confessions Another cause of wrongful convictions are false confessions - They're a factor in 25 percent of DNA exonerations in the United States.

They're usually not the result of false memories, but the stressful conditions of police interrogation.

There are three main errors that lead to false confessions: The Misclassification Error, where investigators wrongly classify an innocent person as guilty; The Coercion Error, where this person is interrogated in an accusatory way that often involved lie about evidence and repeated promises or threats; and The Contamination Error, where after a false admission is given, they pressure the suspect to provide a story, and investigator often supply the facts of the crime.

This "post-admission narrative" is really important for the confession to seem real.

These techniques work because we're easily influenced by suggestion and reinforcement, and in some cases it begins to appear easier to confess than to continue to deny guilt.

Studies have shown that young people and people with mental illness or impairments are more likely to make false confessions.

People with poor memories, low self esteem, high levels of anxiety and low assertiveness are too.

This type of false confession goes at least as far back as the Salem Witch Trials in 1692 - About half the women accused of witchery were tortured into admitting it.

But confessions can also be voluntary, they're more likely to come from those suffering from mental illness.

When actress Elizabeth Short was murdered in 1947 more than 50 people confessed.

More recently, Donovan Allen falsely confessed to killing his mother - after an overnight, 14-hour long interrogation.

He later stated that his confession was false, but he was still convicted and spent 15 years in jail before he was exonerated by DNA evidence last December.

While no legal system is perfect, I think it's important to point out that many have different policing practices.

North American police are trained in the "Reid Technique", this accusatory process where police lead a suspect to believe they're guilty.

In Australia, England and elsewhere in Europe, police are trained in "investigative interviewing, which emphasises that the interview with the suspect is part of an ongoing investigation.

Making a Murderer is full of examples of false eyewitness testimony, and wrongful confession.

Our memory isn't perfect, and the science suggests that the discovery of information should take priority over a confession.

If you have seen Making a Murderer, let me know your theories down in the comments or on Twitter.

I am interested in what you have to say because I have lots of other thoughts that weren't appropriate to include here so I'd love to chat to you about it.

And I'll see you next time.