Sana Khadar

Rebecca says a really clear example from Australian history of how people might judge someone based on their behaviour and believe that they're engaging in deception is the Lindy Chamberlain case.

You're probably familiar with this case, but if not, Lindy Chamberlain was accused of killing her nine-week-old baby daughter, Azaria, while her family were camping at Uluru in the Northern Territory in 1980.

In a trial that received enormous public attention and media coverage, Lindy was convicted by a jury of 12 people in 1982 of the murder of her daughter.

In Lindy Chamberlain's case, it was four years before new evidence, the discovery of one of Azaria's pieces of clothing near a dingo den, would lead to her acquittal and release from prison, where she'd been serving a life sentence.

A final inquest in 2012, 32 years after the original event, confirmed that Azaria Chamberlain died as the result of being attacked or taken by a dingo.

From ABC Radio National, this is All in the Mind.

I'm Sana Kadar.

Today, it's part four of our four-part series, Forensic, on the psychological tools police use to crack crimes and how they can sometimes fall short.

Okay, so if there aren't any solid behavioral ways of telling whether someone is lying or not, what about looking at brain activity?

This is an area that's long been of interest for researchers and law enforcement.

The idea that you could scan someone's brain and tell if they're lying or not.

But there's a core challenge when it comes to brainwaves and lie detections.

Arthur Lee is an assistant professor at Boston University in the United States, and he researches complex mental states and how you might decode them using neuroscientific methods.

A couple of years back, he and colleagues at the University of Berkeley turned to a puzzle that had plagued science for decades.

Because as Arthur says, there are now ways to detect whether someone is lying with some level of accuracy, at least better than chance, in lab experiments.

But those same tests do a very poor job discriminating deception from other emotions or states in the brain, like selfishness or nervousness.

That means you can get false positives.

And in the real world, that could translate to false convictions.

So the team set out to create a kind of foundational experiment, trying to get closer to what lying actually is.

And the experiment they ran to do that comes from the 2013 Martin Scorsese-directed, Leonardo DiCaprio-starring film, The Wolf of Wall Street.