The author here makes an interesting claim: No one - not even habitualy violent people - can start acting violently without first taking time to prepare themselves mentally to commit a violent act. And also that during this process their bodies will send nonverbal clues that violence is about to occur. This will happen on an unconscious and physiological level and is therefore impossible to prevent, regardless of any conscious attempts to conceal a violent intent. This is applicable to both cold-blooded criminal violence and violence that occurs as a result of extreme emotions.
As a result - according to the author - these certain nonverbal signs will always precede eruption of violence. (And therefore a person aware of these signs will be able to avoid being victimized in many situations simply by moving out of the proximity of a person whose body displays such signs.)
The author lists only one exception to this rule: people so severely mentally unstable that it is hard to believe they can be anywhere else than locked up in a mental ward.
As to what are these signs in particular: Unfortunately, the author refers here to the book "Manwatching" by Desmond Morris. Outside of the reference to the book, he only lists a few broad categories: "They range from physiological (Skin flush/pale, muscle tension, breathing, etc.,) to motion (how someone moves while under the influence of adrenaline) and to speech (cadence, tone, pitch)."
While I don't know much about this topic, neither from theoretical sources nor (thankfully) from my own experience, I find it surprising because of:
- The common adage that for most hardened evil-doers killing a man is just like killing a mosquito;
- The doubt how could such a hard limitation evolve alongside the inclination to use violence (which as history shows humans seem to have) - after all giving early warnings is not something a person inclined to commit violence would likely want and also a hard need for a time for preparations can be lethal when facing a surprise attack and circumstances that demand immediate response in order to survive;
- Does this also apply to psychopaths? Because from what I was reading about them I find it odd. Yet these are not always found in mental wards, so the author doesn't count them as exceptions.
- I used to believe that for people with formal training, high experience or simply a fair amount of self-work, a person can bring themselves to acting on a "decision -> action" model, rather than on a "decision -> mental preparations which take time and during which the body sends outstanding phisiological signs -> action" model.
Is it an accepted scientific fact that no man - barring those in mental wards - can commit a violent act without first needing time for mental preparations and without having their body give out easily recognizible nonverbal signs?