What are microexpressions?

We have heard them mentioned again and again in series such as Lie To Me, being "protagonists" in the art of determining if a person is lying or not; We know they have to do with the expressions of our face, but what are they really? How do they manifest?

The microexpressions are involuntary movements of the muscles of the face, in especially emotional moments and that are related to a situation that can cause us anxiety; either for positive or negative reasons. Currently, it has been determined that the seven basic emotions (Happiness, anger, sadness, surprise, contempt, fear and disgust) can not be "falsified", because the muscles of the face move, in most cases, automatically, and there is no way we can reproduce those movements in a perfectly conscious way, even with a lot of practice. Even professional actors, whose work is precisely in that falsification, could not be more effective than those not initiated in the performing arts if they face a situation of imminent danger or deep emotional stress, because their reaction will be as primary as ours. .

Automatic and involuntary

The microexpressions are not called precisely because they are very small, but because their duration in the human face is incredibly short (approximately one twentieth of a second). At such speed, and combining it with conversation, body movements, manual gestures and lighting (all the elements that distract), it is very possible to ignore them. That is why for a true study of those micromotions, it is necessary to film the subject in high definition, so that we have the possibility to see the recording again and again, if possible, frame by frame.

To facilitate its study, Paul Ekman, an American scientist, created the Facial Action Coding System (FACS), which is a method for classifying the movements associated with the muscles of the face. Since the combination of the movements of the individual muscles would be a titanic but impractical task, Ekman decided to group the muscles into "groups" or units of action, in such a way that their classification was easier. Of course, the phrase "easier" is a euphemism that falls short, because even with this simplified approach it is possible to count more than 10,000 different facial expressions.

The "Wizards Project"

Ekman carried out an investigation called "The Wizards Project (magicians)", later called Project Diogenes. It was to determine what percentage of the population was able, in a natural way, to determine at a glance if a person is lying or not. The so-called "Magicians" that determined the study, were those people who could locate lies with an effectiveness greater than 80% (presumably for its facility to detect microexpressions in a natural way), while an ordinary person is not much better than a person. 50% random The study revealed that only 0.0025% of the population has this ability, because of 20,000 people studied, only 50 met the criteria. Facts like this have helped to feed the "myth" of mentalists who are able to read people's minds, when in reality they are simply individuals with an excellent capacity for observation.

Practice makes a master

There is also an online tool called Micro Expression Training Tool (METT) which is a very simple flash application where we can learn about microexpressions and the different types of emotions, which muscles are involved in which manifestation and practices or "drills" to review our abilities. Obviously, as we move with the tool, it becomes progressively more difficult; and on the other hand, the exercises that previously seemed impossible to us begin to be solved with great ease, since our brain is getting used to seeing precise areas of the face that are common to several emotions.

Current applications

The study of facial microexpressions has proved its worth in many different fields such as criminology, psychology, medicine and even 3D character animation.

Hanging

Hanging, according to Tardieu is defined as an act of violence in which the body taken by the neck in a tie tied to a fixed point and left to its own weight, exerts on the suspender loop a strong enough traction to produce abruptly the loss of knowledge, the arrest of vital functions and death.

The anoxemia by hanging is aided by its ease of handling, since it is easy to get a rope and a link where to hang it. For death to occur, it is enough that part of the subject is hung and not the whole person, some people have been found with knees on the floor or even semi-sitting. This is achieved because only 2 kg is necessary to obliterate the jugular veins, 5 kg to obliterate the carotid arteries, 15 kg to obstruct the trachea and 25 kg to suppress the permeability of the vertebral arteries.

There are hanging by suicide, accident, judicial execution, suicide is the most common, the accidental is given by children playing the "hanged". The judicial is by judicial order or death penalty. The crimes are often masked by resorting to "suspension" leaving the authority thinking that it is suicide. Suspension is a term used only for corpses that are hanged, but died of something else. If he has not died from anoxemia, Tardieu's spots are not found in the suspended.

Mechanism of death:

When the knot is in the mouth or under the chin and the rope slides well, the occlusion of the vessels and airways occurs rapidly, leading to rapid death, producing a pale face. If the knot is on one of the sides, it is seen in front of the ear, and the vessels on the opposite side are semipermeable, congestion occurs due to the suppression of the venous return, producing the cyanosed face.

When the knot is below the chin the head is back

When the knot is in the neck the head is forward.

Symptomatology of the hanged: Three periods are considered

'Hanging'

1. Anesthesia: presents the following symptoms

Heat sensation in the head

Ringing ears

Visual disturbances

Brain clumsiness

Intense pain in the neck

Loss of consciousness

2. Convulsive period:

Contractions of the muscles of the face (grimaces)

Uneven movements of upper and lower limbs: can cause injury to the subject

3. Final period due to anoxemia:

Precedes death

He can be removed and with care he will come back to life for a few hours, but he will die from the effects of the shock or hypostatic pneumonia

When it comes to the emission of urine and feces, it is impossible for him to live

Death is prevented by artificial respiration and if there is no damage to bodies or spinal cord.

Autopsy:

Pale face color, muscle tone and tongue position have little value.

The groove must be carefully studied: its direction, shape, appearance, consistency and depth. If the bond is hard and thin, the groove will be deeper, well-limited edges and the marked permeation of the dermis. It is considered a hard groove. If the material used is a belt, the groove will be soft.

There are unique, double and rarely triple grooves, depending on the number of bends of the loop or the number of these. The grooves below the larynx are rare.

The grooves can be:

Incomplete, complete

 

Oblique from front to back and from bottom to top, leaving the highest part in the knot

The bottom of the sulcus is pale and cyanosed by blood plasma.

The lower edge less marked unlike the upper part of the groove, there are ecchymosis and blood disorders, there is tearing of the carotids, and blood may be spilled in the area. There is dislocation or fracture of cervical vertebrae.

In thorax, there is pulmonary congestion, subpleural emphysema and bronchi full of mucus.

The brain is congested or ischemic, according to the handles around the neck

The diagnosis about the cause can give us data on whether the hanging is the cause of death, or if it is a suicide, a crime or an accident.

Branches of Criminalistics

Within the criminology there are technical applications of the work of different disciplines, auxiliary sciences and expert laboratories, among which are:

· Forensic anthropology: is the application of the science of Physical Anthropology to the legal process. To be able to determine the sex, size, age, ethnic group, and even reach the facial reconstruction of human remains. To be able to determine the sex, size, age, ethnic group, and even reach the facial reconstruction of human remains.

·Forensic ballistics: science that analyzes the firearms used in the crimes. It usually includes the study and analysis of projectiles and impacts determining the caliber of the fired weapon.

·Dactiloscopy: is the set of techniques and procedures that have as purpose the study and classification of fingerprints; using powders, iodine vapors, sodium cyano-acrylate or by means of the laser beam.

·Documentscopy: discipline related to the practical and methodical application of scientific knowledge, with the purpose of verifying the authenticity or determining the authorship of the documents.

·Hair and fiber study: Through chemical study it can be determined if the hair in the study is about human or animal hair, as well as other characteristics.

·Forensic Photography: The participation of the photographer to make the photographic fixation of the scene and everything related to it is fundamental; however, it is only the first part of his work, since later he will have to go to the forensic photography laboratory to carry out the development of the material with which the opinions will be illustrated.

·Forensic genetics: The study of biological material, such as saliva, semen, blood, hair, and other tissues, allows the typing of deoxyribonucleic acid (DNA), a modern identification method that, due to its great precision, has been called genetic fingerprinting.

Hematology: In this specialty the application of chemistry is essential if a stain that was found in the place of the fact is blood and if it is animal or human; in the case of human blood, the groups, subgroups and the RH factor will be determined.

·Forensic Medicine: If it is considered that the laboratory is the place where scientific research works are carried out, either the necrocomium or the Forensic Medical Services can be estimated as the laboratories that the doctors use for the thorough study of the corpse, and to determine their identity and cause of death.

·Forensic dentistry: is the application of dental knowledge for identification purposes and useful in Labor, Civil and Criminal Law. It is the branch of dentistry that deals with the management and proper examination of dental evidence and the assessment and presentation of dental findings, in the interest of justice.

·Forensic chemistry: It is the branch of Chemical Science that is in charge of the analysis, classification and determination of those elements or substances that were found in the place of the facts or that could be related to the commission of an illicit.

·Forensic toxicology: is the branch of toxicology that studies the methods of medical-legal investigation in cases of poisoning and death.