At the moderator’s suggestion, I’m breaking this off into a new thread
Body language is notoriously unreliable at revealing deceit
Specifically, Bond and DePaulo (2006) conducted a meta-analysis regarding body language as a predictor of deceitful behaviour and found no relation between the two. In a separate meta-analysis conducted by Sporer and Schwandt (2007), twelve observable behaviours, including eye blinking, gaze aversion, postural shifts, hand movements, etc., were reviewed, and none were found to be correlated with deception. Three additional studies conducted by Wiseman et al. (2012) evaluated whether eye movement is a useful predictor of lying, with all three concluding it was not a useful predictor at all.
In addition, different cultures have different standards for body language - some children are taught to look you in the eye when speaking, while others are taught that this is rude and aggressive. Some mental conditions cause blinking, or hand movements - but don’t make that person a liar. It’s a bad idea to imagine that you can tell if a story is truthful based on appearances. The coherence of the testimony and how well it matches with other evidence is a much better approach.
I think that some people expect another person’s body language to be exactly as an actor would portray it. In the case of someone under extreme duress and emotion, few if any people will react the way an actor imagines it.
I detest when I choose my words carefully, intending them to express what I wish and meaning to be bound by what I said, only to have someone suggest that my tone, facial expression, or body language say something other than the words that came out of my mouth.
It’s been quite a few years, but for a paper on body language I reviewed over 30 studies on body language, focusing on judging truthfulness. Virtually all of them reached the same conclusion – people are very bad at determining anything from body language. Even law enforcement failed completely, with the exception of the Secret Service, which seemed to be pretty good at evaluating body language in regard to honesty. There was no information on how they did this.
Body language is probably something that can be quantified by averages, or bell curves, but those things are useless in judging an individual in a single situation.
They could work in assessing a large group-- the 10,000 employees at corporation X tend to be deceitful, as judged by body language (and supported by other factors, such as hard evidence that some sort of deceit must be occurring)-- none of which says anything about causes of deceit.
One guy, in a 20 minute interview with no context, cannot be judged to be anything based on body language.
If that were true, then actors wouldn’t be able to communicate things without words. There are a few things, like closing off your posture when you are uncomfortable, that happen when you are physically uncomfortable, as in, ill, and carry over to being uncomfortable with a situation enough you feel physically uncomfortable.
But no, nothing without some kind of a direct line to a physical experience has a lot of validity outside of culturally transmitted ones in adults, which therefore require cultural context. You would have to know be able to account for the majority of the cultural experiences of the group you are looking at for this to be useful, and again, it has to be a quite large group.
You begin to get weak correlations, which, to repeat, have nothing to do with CAUSATION, and don’t demonstrate very much that is useful.
I would say that, by definition, body language reading is confined to unconscious, non-deliberate postures. Intentions and feelings are thereby supposedly revealed. Trained actors and others who can mold their bodies during performances are excluded from consideration.
I wonder whether that matches other people’s understanding, or whether there is both conscious and unconscious body language (or whether there’s a clear distinction between the two). If I use my facial expression, posture, etc. to deliberately project confidence, or warmth, or menace, does that count as body language?
My understanding of polygraph techniques - when used appropriately - is that you’re using the device to try and narrow in on locations in the story that the suspect is telling, that they seem less confident in. The device helps you to identify those moments and thus prompts you - the inquisitor - into questioning that part more. As you do so, if they’re lying, then they’re more likely to have to invent details on the spot and thus more likely to create an inconsistency with other parts of the story and prove themselves a liar by contradiction or they just by come up with something completely nonsensical in a fluster. Or, if they never reveal any inconsistencies, they’ve still given a lot of information that you might be able to double-check against documentation, video tapes, call logs, etc. and catch them in a lie via evidentiary contradiction.
I’d expect that body language can help in similar ways. If there’s a sudden change, it might clue you in on what areas to question more deeply.
But it’s still mostly a matter of asking intelligent questions and then coming up with ways to double-check all of that against the evidence.
I have a great deal of experience with this in the field, having conducted hundreds of investigative interviews (perhaps 1,000+, I’ve not kept count) and taught courses that included the topic. Speaking from that experience, body language most certainly can indicate truthfulness under appropriate circumstances, though it is just one consideration.
It states (p. 216, bold emphasis mine): “To understand deception, researchers conduct experiments. They arrange for people to lie and tell the truth, and for others to judge the veracity of the resulting statements. For convenience, we call the people who lie in these experiments senders. the truthful and deceptive statements messages, and the people who judge these messages receivers. We are interested in receivers’ accuracy in judging senders’ veracity.”
The flaw with that approach is that the senders are not under real world stresses that affect their expressions (verbal and non-verbal). They’re tasked with telling relatively insignificant lies or truths. Put simply, study participants lack sufficient skin in the game.
By way of illustration, I like to think I’m reasonably successful at deceiving other players in low stakes board and card games where deception is an aspect of those games. However, I’m far less certain I would succeed in a high stakes poker game (with serious money on the line) or if I were being interviewed after having perpetrated a serious crime (with my liberty at stake).
I do agree that reading body language can be difficult and should not be the sole basis for reaching conclusions about truthfulness. There is a lot of variation in human communication and some people are very good liars (i.e., actors). Inversely, some people are nervous wrecks even when telling the truth.
ETA: I’d be interested in reading any studies that concocted creative ways to incentivize participants similar to a real world situation.
Yeah there seems to be a convension in TV / film that actors always convey their inner feelings, even in scenes where, in-universe, they are meant to be hiding their feelings (I can link some examples, but it would likely lead to a hijack). I guess we’re so used to it now that we would be confused if an actor did otherwise.
But yeah, in the real world, people are much better at pretending and/or just simply have a more neutral expression and demeanor most of the time.
You can probably infer fairly effectively, at least in broad terms, what his emotions are while you’re talking to him. (Or, if he’s an accomplished actor, what emotions he’s deliberately trying to mimic.)
What you can’t reliably infer from his body language is whether he is being truthful in whatever factual assertions he’s making. There are a shit-ton of people who can lie convincingly while conveying sincerity and candor by their body language. There are also a shit-ton of people whose body language makes them seem shifty and evasive while they’re speaking the honest truth.
Emotional affect is not a valid indicator of reliability or truthfulness, so all the “reading body language” blather is just wishful thinking.
The whole picking apart body language thing is just another element of rape culture. There’s not any one way a victim of sexual assault holds herself when talking about an assault. Everyone becomes a Jr. detective when they need to prove a woman is lying, but they don’t apply those same standards to their evaluation of the alleged perpetrator. I remember the Kavanaugh case showing photographs of Christine Blasey Ford smiling in response to a joke, with some people (women, especially) saying, “No REAL victim of rape would smile like this!!!” As if you never smile again after you are assaulted? It’s so weird the standards we apply to sexual assault victims to prove themselves worthy of our empathy.
Not tot mention all of those “guaranteed hook-up techniques” that apparently use things like mirroring body language to help you entice a woman to sleep with you? I’ve only heard of these online and 24th-hand so no idea about details.
There are no accurate means of judging reliability and truthfulness of ongoing or future actions. Even judging the reliability and truthfulness of past words and deeds is highly limited. Best advice I ever received, “Don’t believe anything you hear, and only half of what you see”. Relying on and believing people is always a risk, the most you can do is assign reasonable odds of confidence or betrayal based on past behavior.