After covering a series of high-profile true crime cases, I’m ashamed to admit how long it’s taken to pick up on the tongue flick as a behavioural giveaway of some significance.

It was probably thanks to the LIVEFEED video in the Henri van Breda axe murder trial, that I actually began to really notice it. Because it happens so quickly, you tend to miss it in real time, or even in television coverage.

Since the LIVEFEED was immediately available on YouTube, I was able to go back and review what I thought I’d seen and heard in court, and that’s when a whole new world opened. Henri often lifted his hand just as his tongue poked out, or just as his lip would snarl. It was virtually impossible to catch this unless one slowed down the YouTube video and rewatched it again and again.

Then I noticed the same thing in the Rohde case. Then you start seeing just how often it comes up in true crime. When you realize it’s out there, it starts coming out of the woodwork. What you want to watch out for, besides the tongue flick itself, is the context within which it happens. What is being said, what idea is being brokered when the person flicks their tongue?

Below, John flicks his tongue as he’s congratulating himself about “the point at which justice comes into our system.” He’s referring to the Grand Jury system, and implying the Grand Jury voted not to indict the Ramseys, when in fact they had voted to indict. Watch the clip here.

In the screengrab below Patsy is explaining that the $100 000 is for the arrest and conviction of the killer of their daughter. If the killer was under age 10, then Colorado law wouldn’t even recognize the crime, so there could be no arrest or conviction, and so there was no way that reward could be paid out.

Patsy’s tongue flick happens as she says: “We feel there are at least two people on the face of this earth that know…” Uh-oh. Watch the clip here.

Burke’s tongue flick happens when Dr Phil is taking him through the morning when they discover JonBenet is missing. He describes Patsy coming into his room, and then a cop coming in and shining a flashlight [Burke pretends to be asleep]. When Dr Phil says: “It’s still dark when this happens…” Burke pokes out his tongue. Watch the moment here.

In the Madeleine McCann case, Gerry’s tongue flick happens immediately after he says: “Everything we’ve done is to increase the chances of her being returned.” Then he looks down, and the flick happens. Is that true? Is everything done to increase the chances of Madeleine being found and returned to them? Watch the clip here.

What prompted Scott Peterson’s tongue flick [below]? He says: “A lot of the questions are ‘how do you stay focused and keep working…?'” Does Scott mean the questions are about him continuing with his life almost as if nothing has happened? If so, part of the answer to that may be his affair with Amber Frey.

In the same interview he says “it [the affair, which by then was public knowledge because Amber had told the media] had nothing to with it…” and then “I had nothing to do with it.” Didn’t it?

Read the analysis on Chris Watts here. He does more than one tongue flick in his seven minute interview.

In the Rohde case, which is still sub judicae, Jason Rohde [accused of murdering his wife and staging it to look a suicide] not only flicks his tongue often, but shrugs constantly.

Henri van Breda was an excellent case to learn to catch the tongue flicks. Because of his laid-back demeanour on the stand, and his well-groomed and educated manner of answering questions, you tended to miss the tongue flicks entirely. Only when making a close study of the livefeed, watching snippets repeatedly, did you begin to notice the many times Henri would touch his face. Behind his hand you saw the tongue reflexively slipping out, and the lip curling, as if to hide a nervous smile or twitch of the upper lip.

Below is a rare screengrab where his face is not obscured by his hand, although his head is turned away from the camera slightly. On this occasion, the convicted triple axe murderer was asked to demonstrate – using a balsa wood prop of the axe – how the axe murderer bludgeoned his father while he [supposedly] watched from elsewhere in the room. According to Henri, the attacker laughed while raining axe blows on his father in particular. It may be that his hand isn’t blocking his face on this occasion because it’s holding the axe.

Watch the relevant clip here.

What’s the actual significance of the tongue flick? It could be several things. It could be the psychological idea of tucking into a good meal, in the sense that what’s being asked is something of immense value, but the suspect is determined not to give this information up. As a result, there’s a sense of relishing this delightful leverage, of knowing something someone else doesn’t.

It may also be to hide another microexpression, like a smile, or a nervous curling of the upper lip, and in this sense the tongue flick might be reflexive.

Often we associate a flicking tongue with a snake. Snakes flick their tongue, but that is done to smell. Human beings aren’t trying to smell when they flick their tongues, except that those questioning them are trying to intuit something. So in a sense, there is this psychological effort to perceive something, to smell something. The tongue flick intuits that on a primal level. The suspect is asked a series of questions which the suspect probably could offer a lot more information. This information is on the “tip of their tongue”, but there would be dire consequences if this information is simply volunteered.

Also, the suspect tends to know before he is asked what is being asked [or suspected] of him. So when the question is fielded, often on camera, there is a sense of savouring it, almost as one would a nice meal.

The tongue flick’s real value, as I’ve mentioned before, isn’t that it happens, but when it happens. Catch the tongue flick and then go back and see what prompts it, and a world of psychological possibilities is revealed, including the crown jewel in unsolved true crime cases: motive.