James Bullen

The other police mistake the undercover cop for the perpetrator of the crime.

They catch him...

Kenny Conley completely misses what's happening metres away from him.

What is it that makes some people notice and other people not?

Is it just random chance based on how the experiment runs or is it something intrinsic to some people?

Recognising that this strange phenomenon exists is important, Hayley Cullen says, because it influences how eyewitnesses are seen in a courtroom.

Our bias towards thinking that someone would notice a crime happening right in front of them is so strong that when they don't, we don't trust that person.

It does seem totally bizarre that our brains would do this, but Hayley says inattentional blindness is normal and healthy.

Along with inattentional blindness, another factor that means an eyewitness might not clock what's going on is the idea of ambiguous crime.

An example of this, which Hayley has written about, is the case of Cheryl Grimmer.

And you've kind of alluded to it there and mentioned it, but kidnapping as an ambiguous crime, what does that mean?

And you've done some experiments that test kind of eyewitness reactions to kidnappings.

What did you do and what did you find?

So in one version, the scene just ends while the girl and the older woman are talking to one another.

There's no crime that happens.

Then in the third version, the video ends with what they call the unambiguous crime.

Hayley says that could change the way these kinds of experiments are done in the future and what we understand about how eyewitnesses make sense of what they see.

As we talked about right at the top of the episode, the stakes are high here.

Eyewitness testimony is a powerful piece of evidence in the justice system, and it can make or break convictions.

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