Facial Expression of Emotion

from theory to application

A. Freitas-Magalhães

FEELab Science Books

1st Edition 2011

 Also by A. Freitas-Magalhães

Facial Expression of Emotion. Encyclopedia of Human Behavior, Elsevier/Academic Press, 2010.

ISBN 978-0-12-226920-2

Emotional Expression: The Brain and The Face (Vol. 2). University Fernando Pessoa Press, 2010.

 ISBN 978-989-643-061-0.

Emotional Expression: The Brain and The Face (Vol. 1). University Fernando Pessoa Press, 2009.

ISBN 978-989-643-034-4.

The Psychology of Emotions: The Allure of Human Face. University Fernando Pessoa Press, 2007.

ISBN 972-8830-84-7 - ISBN 978-989-643-031-3 (2nd Ed., 2009).

The Psychology of Human Smile. University Fernando Pessoa Press, 2006.

ISBN 972-8830-59-9 - ISBN 978-989-643-035-1 (2nd Ed., 2009).

           For Msuasy

Facial Expression of Emotion:

From Theory to Application

by

A. Freitas-Magalhães

Published by

FEELab Science Books

www.feelab.org

Copyright © 2011 by A. Freitas-Magalhães

Cover design by S. Po

Book design by S. Po

All rights reserved.

No part of this book may be reproduced in any form or by any electronic or mechanical means including information storage and retrieval systems, without permission in writing from the author. The only exception is by a reviewer, who may quote short excerpts in a review.

Printed in Portugal

First Printing: March 2011

ISBN-978-972-99700-3-0

Abstract

Reading the map of the face remains a challenge to modern science. Facial expression of emotion can have a contagious effect among individuals in their social interaction. The debate on facial feedback and learning, in their cerebral, physiological and situational aspects, is well documented in the literature. The face has always been seen as a mechanism of adaptation and survival, a view borne out by empirical research. Of the various theories on the facial expression of emotion, the holistic approach, which postulates that facial expression is the result of diverse and complex moderating variables, currently has most followers.

Keywords: culture, emotion, facial expression, human brain, nonverbal communication

Glossary:

Facial expression Neuromuscular activity via which messages and signals are emitted.

Emotion Spontaneous and intense neuropsychological reaction which makes the organism produce an action.

Nonverbal communication The expression and perception of nonlinguistic signs between individuals.

Culture A set of meanings, attitudes and behaviours specific to a given cultural group.

I. INTRODUCTION

The face is the most visible part of the body. Hence its vital importance in the psychosocial development of the individual. The face is a complex and many-dimensioned system which has been extensively studied over the years (Freitas-Magalhães, Castro, Batista & Santos, 2010). The face is capable of expressing over 10 thousand different emotions. Early research on the facial expression of emotion concentrated on identifying and characterizing the structural nature of facial movements (e.g., Hjortsjö, 1969; Izard, 1971). Later, attention shifted to identifying and characterizing the functional nature of these same facial movements. Researchers in the field of facial expression of emotion have now turned their attention to the implications and applications of facial expressions in diverse social contexts (e.g. healthcare, justice, education). Every face is unique, the stamp of the individual, and no two faces are identical (Freitas-Magalhães, 2009b; Timothy & Laird, 2009). However, many patterns of facial behaviour are shared and pass from one generation to another. Facial expression functions as a form of adaptation. So is the face like a genetic code which we gradually decipher in our social exchanges over the course of our lives? That's a question which continues to provoke scientific debate. Current scientific research on the facial expression of emotion owes much to the work of researchers such as Bell, Darwin, Duchenne, Schlosberg, Landis, Hjortsjö, Tomkins, Ekman, Fridja, Izard, Osgood, Fridlund, Russell and Camras. The identification and recognition of a facial "program", with consequent measurability, has preoccupied many researchers over the years. For example, Bruce and Young (1986) analyzed face processing as a set of seven types of information code. Is a theoretical model that involves neuropsychological dissociations to access specific semantic information of facial expression recognition. Other theoretical approaches (i.e., Burton, 1998) suggest the involvement of artificial neural networks derived from complex systems. Emotion may or may not provoke a facial expression; and facial expression may or may not be prompted by emotion. This is why it is so important for us to understand the brain-emotion-face process. Each emotion (and its accompanying perception) has its own associated neural circuits. It's essential, therefore, to understand the traits on the human face put there by the emotions generated in the brain. Human facial expressions are the result of muscular movements which express emotional states or signals. Behaviourist and geneticist approaches examine the use and meaning of the muscular movements of the face - eyes, nose, mouth, eyelids, eyebrows, forehead, neck. Reading the map of the face remains a challenge to modern science. Facial expression of emotion can have a contagious effect among individuals in their social interaction (e.g., Bänninger-Huber & Gruber, V., 2010; Freitas-Magalhães & Castro, 2010b). The debate on facial feedback and learning, in their cerebral, physiological and situational aspects, is well documented in the literature. The face has always been seen as a mechanism of adaptation and survival, a view borne out by empirical research. Of the various theories on the facial expression of emotion, the holistic approach, which postulates that facial expression is the result of diverse and complex moderating variables, currently has most followers.

II. EMOTION: A COMPLEX AND MULTIDIMENSIONAL PHENOMENON

Over two centuries have passed since Bell (1806) published his anatomical groundwork of facial expression, a work which was to form the foundations of later scientific research and even today is frequently cited. Bell was the first researcher to offer a definition, albeit tenuous, of emotion. The definition of emotion is not consensual, as it is a complex and multidisciplinary phenomenon. For example, some feelings are associated with emotions. But if all emotions generate feelings, not all feelings derive from emotions. The difference lies in duration, intensity and frequency (Freitas-Magalhães, 2008a). Despite the difficulties in arriving at a consensual definition of emotion, the literature does agree on the importance of neuron, motor and experiential processes. Emotion is an automatic, intense and rapid response - either conscious or unconscious - to the world around us, and a neuronal impulse which induces the organism to perform an action. The functions of emotion are associated with adaptation and expression. Emotion functions as a catalyst between conduct and the environment, and is a prelude to action. Emotion plays a crucial role in the learning process. Experiencing emotion allows us to learn emotionally, so we can deal with future situations; and emotion is a means of preparing us for action. Emotion manifests itself in the form of kinesic and kinetic processes in the scope of the repertory of non-verbal communication. It contributes to the expression of feelings and may also reflect social status and power in terms of facial configuration. The different types of emotion help make communication more fluent and also assist in the identification and comprehension of defence mechanisms and rules of interaction (e.g., Freitas-Magalhães & Castro, 2009a; Nikittin & Freund, 2010). The components of emotion are conscious experience (sensation), physiological reactions (organs and systems of emotional activity) and expressive behaviour. Emotional systems have been extensively discussed in the literature and include cognition, facial expression and the activity of the autonomous nervous system (ANS). The universal recognition of facial expressions derives from an innate program for each of the basic emotions (Darwin, 1872; Izard, 1994). However, changes in expressivity change what is felt. The characteristics of emotion spread the distinctive pancultural signal for each emotion, universal facial expressions determined phylogenetically, the involvement of various signals, the duration is limited, facial expression reflects aspects of emotional experience, the different degrees of intensity for measuring the subjectivity of experience, facial expressions can be inhibited, expressions can be faked, each emotion has its own aspects and each activates an alteration pattern on the level of the autonomous nervous system (ANS) and central nervous system (CNS).

III. FROM THE BRAIN TO THE FACE: AN EMOTIONAL JOURNEY

The general theory is based on the premise that emotion has evolved in accordance with everyday activity; its adaptation implies differentiated patterns for each emotion and that cognition and physiology play a part in the activation of emotion. Emotion is activated in the brain circuits and involves lateralization; positive emotions (Harmon-Jones, Schmeichel, Mennitt & Harmon-Jones, 2011). are governed by the left hemisphere and negative emotions by the right hemisphere; efference, the emotion program implies distinct expression via movement of the facial muscles; and facial feedback, which relates to the proprioceptive, cutaneous and vascular dimensions of facial expression which are influenced by emotion. Facial expression of emotion lasts from 1 to 5 seconds. The vascular theory holds that emotion and cognition function operate via different mechanisms and that changes in facial expression change what we feel, creating or influencing emotional experience. Emotion causes physiological alterations which prepare us for action and which, over the years, evolve on the adaptive and expressive levels. Emotion is a brief reaction, but it can form the basis for the formation of feelings or other conducts. Emotion is a neurophysiological reaction to stimuli which mediate situations of danger and satisfaction. Not all of the emotions occurring in the cerebral structures are conscious. There is an extensive literature attesting that emotion develops in the limbic system, a set of structures located below the cortex and related with the cortical zones. The interaction between the limbic system and the cortex makes us aware of emotion, which may then act as a moderating variable. Emotional processing activates different cerebral structures, such as the hypothalamus and the pituitary gland, whose primary physiological functions are to regulate cardiac and muscle movements. Over the years, the emotional system has evolved to place greater emphasis on the consciousness of emotion (Fridja, 1953). However, no significant evolution has occurred in the primary pulsions. Take, for example, the processing of fear: in the first place, the amygdala (Whalen, Davies, Oler, Kim, Kim & Neta, 2009) registers the stimulus almost automatically, without any interference from conscious mechanisms. The amygdala then notifies the hypothalamus, which triggers a set of physiological reactions. This process occurs almost instantaneously, with interaction between unconscious reaction and conscious response which is not fully understood. Studies have clearly shown that the amygdala is one of the key centres for the processing of emotion, for. it is the amygdala that issues instructions to other brain areas for the appropriate emotional response to be made. The brain functions, therefore, as a kind of dressing room for the expression of emotions which subsequently appear on the stage, i.e. the face. The amygdala plays a crucial role in the emotions, and damage to it can cause selective deficits in the recognition of facial expressions of fear, but also other emotions (e.g., Freitas-Magalhães & Castro, 2010a). The amygdala is comprised of nuclei which are responsible for differentiated reactions. For example, while the central nucleus triggers the immobilization reaction in the presence of a phobic situation, the basal nucleus stimulates the flight response. The different ways in which men and women react can be explained by the way these nuclei are affected by the sex hormones. The amygdala is a repository of experience (Sato, Kochiyama & Yoshikawa, 2010). It operates unconsciously, involving various brain structures (e.g. the thalamus, hypothalamus, hippocampus, cerebral cortex etc.). This is on reason why it is difficult to treat phobias in a clinical context. However, we can - and should - learn how to deal with the stimuli and in this way mitigate the intensity of phobic reactions. In the case in point, the amygdala captures the facial expression and produces a certain reaction. Scientific discussion continues on the issue of whether the activation of emotional reactions is a conscious or unconscious process. Much literature (e.g., Freitas-Magalhães & Castro, 2010d) contends that emotion is initially a physiological reaction to e.g. a threat to the integrity of the system. Once the amygdala has relayed the signal, conscious feeling, involving the orbitofrontal and cingulate cortex, emerges.

IV. FACIAL EXPRESSION: FROM UNIVERSALITY TO CULTURAL INFLUENCES

The research of Ekman and Friesen just over half a century ago made a considerable contribution to our knowledge of the facial expression of emotion (Freitas-Magalhães, 2009). Until then, the study of facial expressions had enjoyed little prestige among psychologists, despite the contributions of Allport, Hull, Osgood et al. At this time, the work of Schlosberg on the representation of the information exhibited by the face drew most attention. Still, very little extended research was dedicated to it. The much needed paradigm shift came with the work of Tomkins (Tomkins, 1962), for whom non-verbal communication - namely facial expression - was a superlatively rich source for the study of human behaviour. Ekman and Izard were influenced by Tomkins' work, particularly with regard to the planning and execution of intercultural studies, in their examination of questions such as Do facial expressions convey universal emotions? How do we interpret facial expressions? The work of Ekman in New Guinea in the late 1960s reinforced the view that, contradicting Mead, spontaneous expressions are universal, while also showing that facial expressions can be influenced by so-called rules of exhibition which are specific to a given culture or social context. Ekman's findings were backed up by the evidence gathered in anthropological studies. Psychologists such as Fridlund (1994) and Russell & Fernández-Dols (1997), however, have questioned this evidence as well as the methods used in arriving at judgements on the display of facial expressions (Katsikitis, 2003). Expressions of fear, anger, disgust, sadness and joy register values of intercultural congruence. Discovery of the universality of facial expression triggered the need to devise methods and techniques of scientific measurement for the evaluation of facial movement. Thus in the 1970s there emerged the Facial Action Coding System (FACS) for the classification of muscular movements, and the Maximally Descriptive Facial Movement Coding System (MAX) for the verification of the most important muscular movements in the identification and recognition of a given emotion. Also at this time the first scientific findings on the measurement of the electrical impulses associated with movements of the facial muscles began to appear. Measurement of the facial expression of emotion continued to be a challenge for researchers. And the principal problem affecting measurement methods already devised was how accurately and objectively these methods could measure. The identification and recognition of facial movements and their association with certain emotions has provoked extensive and heated scientific debate. The techniques and methods devised by Izard, Ekman and Friesen (the FACS was updated in 2002) (Ekman, Friesen & Hager, 2002) in the late 1970s were based on the research of Hjortsjö into the workings of the facial anatomy. Identifying Affect Expression by Holistic Judgment (AFFEX), the Facial Affect Scoring Technique (FAST), the Facial Expression Coding System (FACES) and EMFACS (which converts action units into emotional states), the FACS Affect Interpretation Dictionary (FACSAID), electromyography (EMG), functional magnetic resonance imaging (fMRI), Baby-FACS and FACEM (which measures facial movements in terms of a dozen basic states) are some of the other instruments now used in measuring the meaning of facial movements. Current research also draws on databases (e.g. F-M Portuguese Face, Pictures of Facial Affect and Karoliska Directed Emotional Faces) and software (e.g. METT, SETT, FaceReader, FaceXpress, i-Brain, i-Emotions, i-Smiles).

V. FACIAL EXPRESSION: ITS CONTRIBUTION TO THE STUDY OF THE EMOTIONS

The evidence for the universality of facial expressions has led research to extend into other areas, such as healthcare, justice and education. The scientific community now sees facial expression as a psychobiological phenomenon of considerable interest to the comprehension of human attitudes. Given that each expression is associated with a particular physiological activity in turn associated with a particular emotion, the idea of interaction between a given emotion and the central nervous system gained increasing numbers of supporters, especially in the early 1990s with the work of Davidson and Cacioppo among others. Spontaneous facial expressions are the result of a subjective emotional experience. Typical emotions appear in response to given situations, which bears out the claim that events precede emotions. Facial expression is the mirror of our ontogeny. The ability to give facial expression to our emotions appears at an early stage of infancy (Camras & Shutter, 2010). Thus the face is a fulcral element in human interaction from a very tender age - and indeed is the first means of communication on which we can draw. Emotions occur according to a special process. There are various expressions for each emotion. For example, Ekman catalogued over 60 expressions of fear, which reflects the intensity of this emotion. Each emotion is comprised of specific affective states, and it is the composite nature of these states which determines the differences between the emotions. Facial expressions are seen as evidencing subtly positive or negative states. Emotions may vary in terms of vocal expression, but not in terms of facial expression. And some expressions, such as smiling, are used in various states.

Positive emotions and negative emotions

Negative emotions trigger serious problems which may take the form of e.g. phobias, anxiety disorders, aggression, violence, depression, suicide and eating disorders. For Tomkins, negative emotions produce a specific signal. However, research conducted in the 1990s failed to confirm this theory, pointing instead to the existence of various templates, which supports the differential theory of emotion. Positive emotions represent the satisfaction of the individual. The limbic system is related with sensations of pleasure, diminishing other types of activity which may influence the normal course of satisfaction. According to the literature, there is an association between emotional states of pleasure and zygomatic muscular activity. It also shows that happiness is not always signalled by a smile. For example, the smile of a child is more evident in the context of social interaction than in situations of happiness and can also be observed more in situations of discomfort. The smile is coordinated by the ocular function and success in a sports competition is not evidenced when receiving the prize. The smile is in fact a specific phenomenon of the facial expression of emotion and one of the paradigmatic features of the study of facial expression of emotion, as a multidimensional phenomenon which is at the source of much disagreement among researchers with regard to its causes and functions (Freitas-Magalhães, 2004). One type of smile which has attracted much scientific attention - and yet elicited little agreement - is the so-called Duchenne Smile, which is characterized by zygomatic activity in combination with the orbicularis oculi (Duchenne, 1862; Freitas-Magalhães & Castro, 2009f).

Basic emotions

The human face exhibits basic universal emotions with a muscular configuration specific to each: joy (corners of the mouth raised), disgust (cheeks raised, nose puckered, upper lip curled), anger (eyebrows lowered, eyes narrowed, lips compressed), contempt (chin raised, part of corner of mouth raised slightly), fear (eyebrows raised, eyes wide open, mouth open), surprise (eyebrows arched, eyes wide open, jawbone slack) and sadness (eyebrows slanting from centre to edge, mouth slack).

What does the face show?

Facial expressions are the reflection of the experiences and messages of the endogroup (the group of belonging) and the exogroup (the comparison group). The terms we use to describe emotions are not unique or unequivocal. Once again the intercultural question comes into play. The message generated by an emotion has to be captured instantaneously. The start, duration and end of the movement are the stages which have to be taken into account. Involuntary and momentary expressions activate a particular muscular contraction, giving indications on the type of associated emotion. Positive emotions share a particular expression (e.g. the smile), which can be observed in terms of time, intensity and context. Negative emotions (e.g. sadness) also exhibit a particular morphology of expression (e.g. corners of the mouth, eyebrows) characteristic of unhappy states (Freitas-Magalhães & Castro, 2010f). Some emotions are given no expression on the human face. This means we are unable to identify a facial expression, vocal expression or bodily behaviour associated with them - no discernible pattern or sign of distinction exists. This is a legacy of ontogeny and phylogeny. There is a template at the central nervous system (CNS) level which is unique for the emotions. The fact that an emotion is not linguistically coded does not mean that this emotion does not exist. There can be emotion without facial expression. Research using electromyography (EMG) has detected alterations in the pattern of facial activity. This would seem to contradict Tomkins, who asserts that facial expression is always part of emotion, even when it is not visible. Voice and posture (e.g. head and hand movements) also contribute to the configuration of the emotions. Isolated head movements do not of themselves communicate emotions. It may be possible that emotion can be characterized by vocal expression but not facial expression. Ekman (1992) agrees with Tomkins in contending that each emotion has its facial expression and its vocal expression too. The existence of emotions with no expressive or auditory signal has occupied many contemporary researchers. Ekman (2003) maintains that we must bear in mind certain discrepancies in the mode of facial expression of emotion (e.g. anger as a result of irritability), emotional state (anger as a result of hostility) and affective disorders (sadness as a result of depression).

Facial expression without emotion

People can fabricate and feign the facial expression of emotion. But this occurs when they are not in any emotional state. The literature attests to the distinction between genuine and false expressions. Some muscular movements cannot be made voluntarily. In the latter half of the 19th century, Duchenne (1862) identified the orbicularis oculi, the muscle which surrounds the eyes. This muscle contracts in involuntary smiles but not in voluntary smiles. The orbicularis oculi comprises two portions: the central and the lateral. The first portion can be contracted voluntarily, but the second cannot; and it is the contraction of this second portion which is absent in "false" smiles (e.g., Freitas-Magalhães & Castro, 2009c). Duchenne's theory now enjoys global consensus. Expressions such as anger, fear and sadness also involve specific muscular configurations which cannot be exhibited voluntarily (Freitas-Magalhães & Castro, 2010g).

A special phenomenon: The human smile

Not all smiles are the same. Laboratory analysis of the human smile has established a reference framework which distinguishes between true and false smiles, and which involves identical asymmetry and different amplitude and duration. Distinctions are established between true smiles and false smiles, spontaneous smiles and intentional smiles, Duchenne smiles and non-Duchenne smiles. The Duchenne smile and the social smile are extensively documented in the literature. The first is spontaneous; the second intentional. The Duchenne smile - named after the French neurologist Guillaume Duchenne, who was the first to identify it - involves muscles activated by an unconscious cerebral process. With the Duchenne smile, the lower eyelids dilate and the corners of the eye wrinkle. The smile is an indicator of what its wearer is feeling and reveals the emotional state ascribed to it. Forced smiles point to low levels of happiness. The smile is controlled by emotion. A true smile, which involves activation of the muscles around the mouth and the eyes, reveals joy and involves the motor cortex, the muscle around the eye (which controls movement of the eyelids) and the amygdala. A false smile, however, involves conscious brain structures and the motor and premotor cortices, with the eyes averted and deliberate contraction of the muscles around the mouth, drawing the lips outwards, and also involves the premotor and motor cortices, the frontal cortex and the lesser and greater zygomatic muscles.

Gender and age: Differences and implications

Women are more attracted by faces exhibiting positive emotions in men than in women, regardless of age, while men are more attracted by negative emotions without distinction of gender (e.g., Freitas-Magalhães & Neto, 2003). This is one of the conclusions of research into facial attraction and the effects of the emotions. The procedure consisted of displaying images of faces exhibiting basic and secondary emotions and judgements on identity and attractiveness made by individuals. The findings suggest that women feel more attracted by the faces of men exhibiting positive emotions and belonging to the 18-25 age group, with levels of attractiveness decreasing as age increased. Men feel more attracted by negative emotions in the 18-25 age group, and again the level of attractiveness decreases with age. The findings also suggest that distinct perceptions of attractiveness vary according to the type of emotion exhibited on the face, and that such perception also varies according to gender and age. The conclusions also suggest that facial expressions reflect and determine how emotions are expressed. They confirm the principal effect of the facial muscles (Freitas-Magalhães, 2007a) in the representation and determination of the emotions, while differences according to age and gender were observed. Women claim to feel emotion more intensely than men. Individuals in the 40-60 age group also claim to feel emotion with greater intensity. The findings corroborate the facial feedback theory, according to which the facial expressions exhibit not only emotional experience but also determine the way the basic emotions are lived and labelled (e.g., Freitas-Magalhães & Castro, 2009d; Stanley, Heesacker, Perrin, & Graf, 2010).

VI. EMOTION MANIFESTED ON THE FACE: SOME THEORIES COMPARED

The new scientific approach accepts some associations between facial expression and emotion, but insists the central question is not the associations themselves but the nature of them. This is the real core of the debate on the facial expression of emotion. The facial expression of emotion is influenced by culture, age and gender. It makes reference to multiple standards within the scope of non-verbal communication, which reinforces the behavioural ecology view of the emotions. Spontaneous expressions are rather the reflection of phylogenetic criteria. The smile, according to this theory, appears from the experience of an affective state. It is not an intention of friendship, but a positive feeling. The emotions do have social intentionality, as rational behaviour does, but we must take into account a behavioural disposition characteristic of a certain receptor. Facial expressions can occur when the emitter is alone. With regard to facial expression and the effect of the intensity with which the basic emotions are exhibited, the literature observes that the human face is incapable of displaying two emotions at the same time. The research procedure consisted in collecting information on the intensity of the seven basic emotions (joy, sadness, anger, fear, surprise, disgust and contempt) exhibited by individuals. Muscular-skeletal movements were measured in terms of microexpressions in fractions of a second. Participants were unable to exhibit two basic emotions (e.g. joy and anger) on their face at the same time when asked to do so. The findings show that the brain processes the exhibition of the basic emotions sequentially. The findings also suggest that women exhibit the basic emotions quicker and more intensively than men, regardless of age. Surprise and fear are the basic emotions that both women and men are quickest to exhibit, while contempt and disgust are those which take most time to appear on the face (e.g., Widen & Russel, 2010) The literature also shows that the right hemisphere is more associated with negative emotion than the left hemisphere. For example, the identification and recognition of the basic emotions of fear and sadness tends to activate the structures of the right hemisphere more than the left, while the signals produced are received and processed by the left hemisphere. These signals must circulate in that order if we are to be conscious of the emotions. Facial expression of emotion also activates the right frontal cortex. Emotional information is processed in neuronal circuits and the reaction and response to them depends on the type of stimulus. For example, the positive emotions follow a different path from the negative emotions, for they are intimately linked to the cerebral artery which segregates dopamine, the neurotransmitter responsible for feelings of satisfaction and pleasure. The consciousness and evaluation of the intensity of emotion is the responsibility of the thalamus. Functional magnetic resonance imaging (fRMI) enables us to identify the course of the reaction and response of brain structures. The literature attests that the facial expression we know as the smile is more rapidly identified and recognized (i.e. consciously) than a neutral expression, and that the brain needs only 350 ms for the global perception of emotional interpretation. Emotion is characterized by duration and intensity. Emotion is a guide for adaptive behaviour. Emotion is consensually described as a neuronal impulse which causes the organism to produce an action. Modern evolutionary theories are concerned with the identification of the functional axis of the emotions, arguing that just as emotion can be the cause of facial expression, so the latter can be the cause of emotion. And the recognition of discreet or subtle emotions is a fundamental question in the evaluation of this process. Approaches towards the facial expression of emotion have changed since the late 1970s. Traditionally, expressions such as the smile have been considered as facial expressions. But this is where a range of differences begins to emerge. The new approaches focus on the expression-emotion pairing (e.g., Freitas-Magalhães, 2007b). The facial movements are called signals. Facial expression is viewed as a heterogeneous phenomenon and the point of analysis is the emotional state of who is emitting and who is receiving the message associated with a given facial expression. The communication process is considered, and analysed, in its entirety. The modern era of the study of the facial expression of emotion began in the 1960s with the work of Tomkins, which was later an influence on Izard and Ekman, among others. Tomkins's theory holds that each basic emotion is associated with a unique cerebral emotional process. The basic emotions vary in their degrees of intensity (e.g., Freitas-Magalhães & Castro, 2011). This theory of the basic emotions has received criticism, however. The new approach to the facial expression of emotion stresses the multidimensional character of the emotions, paying particular attention to the components underlying emotional processes (Freitas-Magalhães & Castro, 2010e). One of the criticisms levelled at the theory has to do with the fact that research into the facial expression of emotion is centred exclusively on the judgements made by the receiver of messages. The momentary emotional state of the receiver of these messages is not taken into account. And the judgements made by the receiver do not necessarily correspond with the emotion as lived. This view of the facial expression of emotion stresses the idea that the receiver does more than merely receive and decode the expressed message. The facial expression of emotion involves the emitter in a range of effects. For example, when detecting a lie, the receiver is not merely detecting the lie but also verifying a standard of truth. For the person receiving the message, more than merely verifying the traces of the lie, s/he verifies the truth-framing process. Can the facial expression of emotion predict human behaviour? The traditional theory of the basic emotions is now being re-examined in the light of new approaches, which stress the dynamic processes of the various components involved, with particular emphasis on the social context and its relationship with cognition and activation. Social learning is a dimension which must be taken into account in the process of construction and exhibition of the facial expression of emotion, since the communication process involves both sender and receiver and it is not essential that an emotion be attributed to the message. What's at stake is the universality of this process. In the traditional view, facial expression is always a particular signal of emotion, with the consequent process of decoding on the part of the receiver, regardless of gender and age variables. The process is innate and immediate. It's precisely in regard to the processing of the comprehension of facial expression that the debate and the different approaches emerge. According to the traditional view, the facial expression of emotion occurs according to an innate standard shared by all cultures. According to the modern view, social influence has a considerable effect on this process. In other words, the signal manifested on the human face is interpreted according to different perspectives, since a range of facial traits can be observed for each emotion. No rational evidence for the existence of such a range is known. The research is extensive and the findings are not consensual, principally with regard to the facial expression of spontaneous emotion. And this is a result of the components involved in the cognition process. For example, some emotions are more easily recognized than others. The basic premise is that this process requires that the emotion is part of the stimulus and as such must be immediately recognized, as if it were part of a congenital standard. Now the attribution depends not only on the genetic process, but also on the cultural background of the individual processing and emitting and the individual receiving and perceiving. For example, the literature observes that a smile is not always a sign of happiness, and that the ways we recognize a smile are not in fact consensual. Hence modern theory on the facial expression of emotion argues for the existence of what it calls a minimum universality, pointing to the fact that facial expression can occur in any place at the instancing of a psychological process, i.e. people make inferences based on facial traits. However, judgements reveal discrepancies with regard to identification and recognition. The judgement that the receiver makes of facial traits is summarily expressed as a specific emotion. Yet this process is influenced by our surroundings. The judgement of a given facial expression of emotion is not as simple as it might at first glance appear to be. The process - often the immediate identification of a signal - involves complex variables such as gender, age, affective state and social context. The idea is that the recognition of the facial expression of emotion is not just the recognition of a signal but the result of a learning process of the utility of such a signal in the dyadic process of human communication. In the light of the above, and despite previous research, further intercultural investigation is required, for the effects of the facial expression of emotion are diverse.

VII. MACROEXPRESSION AND MICROEXPRESSION

The analysis of the facial expression of emotion, spontaneous or intentional, addresses amplitude, asymmetry, duration, onset, offset, intensity and head movements. Macroexpressions last between half a second to 4 seconds and can be observed in everyday conditions. Microexpressions last less than half a second and occur when the individual is concealing or repressing his/her feelings. Microexpressions are not immediately detected by the observer. However, with a little training, we can learn to express and recognize microexpressions. "Subtle" expressions are related with the intensity of the emotion and occur only when an individual is undergoing the onset of an emotion. They also appear in response to another individual in contexts of reduced emotional intensity. We can observe a strong correlation between the degree of identification and recognition of subtle expressions and the degree of detection of falsehood or deception. The time taken for macroexpressions to appear and disappear varies between 0.5 and 4.5 seconds, and occurs as part of a normal process of the exhibition of the emotions. The time taken for microexpressions to appear and disappear is less than half a second, and frequently as short as 1/5 or 1/15 of a second. Some expressions involve the whole face, i.e. enlist all the facial muscles at the service of a certain pattern, including the forehead, eyes, cheeks and lower jaw. Facial expressions which involve all the associated components are observed only in the eyebrows, or eyes and cheeks or lower jaw. Analysis can be made in terms of angles (frontal, whole face frontal; 3/4 angle where the face is seen from an angle of 45 degrees, and in profile, where the face is seen from the side, at an angle of 90 degrees). The intensity of macroexpressions can be moderate or strong, corresponding to codes C to E of the Facial Action Coding System (FACS). Microexpressions are of low intensity, corresponding to codes A and B of the FACS. Facial expression is also measured in terms of distance (short, as in social interaction between close friends or family members; medium, as in social interaction among known and unknown individuals, and long, as in the identification of a face in the crowd or at a considerable distance). Recent research has revealed that subtle expressions, but not microexpressions, are a more accurate and useful tool for the detection of falsehood and deception. Thus, learning how to identify and recognize subtle expressions helps us learn how to detect lies (e.g., Freitas-Magalhães, 2009c; Freitas-Magalhães & Castro, 2009e; Vrij, Granhag, & Porter, 2010). Subtle expressions occur only when an individual is beginning to feel a given emotion and in low-intensity contexts. When we identify and recognize a subtle expression, we are identifying the emotion that our interlocutor exhibits and the subtle variations in its expression. To identify and recognize a microexpression, we need to be able to verify an expression visibly replete with emotion in a short space of time (1/2 second or less). In the laboratory analysis of facial expression, a range of methods and techniques are used. For example, Psy7Faces is a method devised for detecting subtle expressions and microexpressions. The Micro Expression Training Tool (METT), Subtle Expression Training Tool (SETT) and SubX are computer programs designed to train us in identifying the basic emotions. The most commonly-used instrument for measuring facial expression is the Facial Action Coding System (FACS), which provides a scientifically rigorous method of classifying the movements of the facial muscles. Current research suggests that traits can be identified and recognized for lie detection purposes. The basic premise is simple enough: if there are different ways of expressing the content of the basic emotions, then profiles for psychophysiological alterations can be devised. The research manual, published in 2002, lists 44 Action Units (AUs) for evaluating facial expression via combinations. For example, the expression of joy maps to AUs 6 and 12. The intensity is measured on a scale of a (trace) to e (maximum evidence). Onset, apex and offset mark the stages during the muscular movement evaluation process.

VIII. NEUROMUSCULAR STRUCTURE AND FACIAL EXPRESSION

The way the brain constructs emotion has been the subject of much in-depth research in recent years. The brain is divided into two hemispheres, and processes information cross-wise: each hemisphere controls the opposite side of the body. Each half of the cerebral cortex has four lobes (frontal, parietal, occipital and temporal), each with a specific function. The temporal lobe regulates certain emotions (joy and anger); the frontal lobe regulates movement and reasoning; the parietal lobe regulates touch, sensations of heat, cold, and pressure; and the occipital lobe interprets the information sent it by the optical nerve. As for the nervous system, of the 12 pairs of cranial nerves it is the facial nerve (VII) which controls the movements of face and neck, as well as the sense of taste. The motor fibres drive the facial muscles and in this way allow us e.g. to move our eyebrows, open and close our eyelids, narrow our nostrils, smile, pull faces and kiss. The muscle around the eye allows us to close our eyes (voluntarily, when we want to sleep, and involuntarily, to blink); the muscle around the mouth allows us to close our mouth or stick our lips out (e.g. to give a kiss); the frontal muscle allows us to raise our eyebrows and frown our forehead; the masseter muscle allows us to chew; the nasal muscle allows us to open and close our nostrils and the temporal muscle allows us to move our temples. Another example of the differentiated movement of the muscles: the expressions made by humans are not exactly the same as those found in the chimpanzee (humans configure joy differently from chimpanzees; when the latter show their teeth they are revealing fear).

IX. THE HUMAN FACE: MODERATING VARIABLES

The effect of visual and auditory stimuli

Visual stimuli exercise more influence on emotional perception than auditory stimuli, and there are gender and age differences in emotional reactivity when the neuropsychophysiology of the emotions is examined via the verification of the visual and auditory effects of positive and negative emotions (Rinn, 1991). The effects of visual stimuli are more visible than those of auditory stimuli both in positive and negative emotional reactions. Regardless of their age, women are more influenced by the visual stimuli of the basic emotions of joy, sadness and surprise. Men are more influenced by visual stimuli of the basic emotions of anger and joy, decreasing in intensity from age 45 onwards. Research has revealed that visual stimuli of fear and sadness are mentioned by participants aged 65 and over.

Effect of skin colour

According to the literature, skin colour affects the psychological perception of the smile. The expressiveness of the smile reveals that women are more influenced by skin colour when they see a smile. Research has demonstrated that our perception of smiles in individuals of a different colour of skin reinforce attachment to the endogroup in relation to the exogroup and facial stereotypes in the context of the rules of social exhibition and theories on the facial expression of emotion. The Smile Perception Scale (SPS), devised by this author in 2003, comprises 19 opposing pairs and measures the factors Evaluation (Ev) and Expressive Movement (EM) in two types of facial expression: the broad-type smile (lips apart, corners raised, both rows of teeth on show, the whole face exhibiting significant physiological alterations, accompanied by muscular movements) and the neutral or unsmiling face (lips together, corners not raised, teeth not displayed, no physiological alterations of face and no muscular movement).

Facial feedback

The facial expressions reflect and determine how emotions are expressed, namely the psychological construction of the emotions and the effect of the movement of the facial muscles. The research procedure involved asking participants to use their facial muscles to express the basic emotions. One of the examples used was fear (“Raise your eyebrows and knit them”; “Stretch your lips horizontally towards the ears”). The participants later noted whether they had felt the emotion represented, and with what intensity. The findings confirm the principal effect of the facial muscles in the representation and determination of the emotions, and age and gender differences were observed. Women say they feel emotions more intensely than men. Participants in the 40-60 age group also claimed to feel emotion with greater intensity. These findings corroborate the facial feedback theory.

The effect of stereotypes

Facial expression and the effect of the smile on the psychological perception of stereotypes show that an individual who smiles is perceived as intelligent and attractive. Smiling people were perceived as happier than those with a neutral expression. The broader the smile, the happier its wearer. Women were perceived as more intelligent and attractive when wearing a superior or closed smile than when with a neutral expression. There were no significant differences in perceived intelligence in men. The findings suggest that smiles affect men's perception of beauty. A smile makes a woman more attractive, and attractiveness increases in linear fashion from a neutral face to a broad smile. The 60-70 age group makes no significant distinction in its perception of the different types of smile and associated psychological characteristics. But this difference is significant in the 18-25 age group. Women tend to underestimate the effect of a smile in other women, attaching greater value to the smile of a man. A smile in itself is the expression neither of intelligence nor beauty - its effect depends on variables such as the gender and age of its wearer and observer.

The smile of criminals

Criminals who smile are more favourably perceived, and seen as less responsible for the crimes they have committed, than criminals with a neutral expression, especially among women (Freitas-Magalhães & Castro, 2009e). Analysis of facial expression and the effect of the smile in psychological perceptions of criminals revealed that criminals who smile are more favourably perceived, and seen as less responsible for the crimes they have committed, than criminals with a neutral expression, especially among women. The conclusion is that women and male criminals are perceived more favourably, and seen as less responsible, by women, while men only make such a distinction in relation to women. Research has also revealed that the age effect is operative in men aged between 18 and 50, for whom there are no significant differences in their perceptions of the facial expressions of criminals. The more serious the crime committed, the less the importance attached to the smile, both by men and women. The findings reveal that this significant reduction in the smile effect is more pronounced in men.

Activation and perception

Findings on the psychophysiology of the smile and the construction and effect of the emotions reveal that the smile not only reflects certain emotional states, it can also help to produce them. Women and men attest to experiencing positive emotions when they smile, and this experience varies according to gender and the type of smile exhibited: women say they feel happier when they wear a broad smile and men when the wear a superior smile, as the literature records. For example, the muscles which are activated when we smile send a message to the brain informing it of the experience of happiness, even when context and circumstance have not actually produced this particular emotion. This is the premise on which the theory of facial retroaction is based. Conversely, neither women nor men say they feel any emotion when they wear a neutral expression. A closed smile is the first indicator of the feeling of happiness, although it has little intensity either in men or women. None of the participants said they felt any kind of negative emotion when exhibiting one of the smile types studied. The findings suggest that wearing a smile has strong therapeutic effects in the induction of positive emotions in diverse social contexts. The smile has been classified into four different types: The broad-type smile (lips apart, corners of mouth raised, both rows of teeth on show, the whole face exhibiting significant physiological alterations, accompanied by muscular movements) the superior smile (lips apart, corners of mouth raised, upper teeth on show, the whole face exhibiting significant physiological alterations, accompanied by less intense muscular movements), the closed smile (lips together, corners of mouth raised, teeth not on show, no significant physiological alterations to the face as a whole, limited muscular movement) and the neutral or unsmiling face (lips together, corners of mouth not raised, teeth not displayed, no physiological alterations of face and no muscular movement).

The effect of visual memory

Women reveal better visual memory in the identification and recognition of human faces, as shown by research (e-g. Freitas-Magalhães, 2009a) into the effect of memory on the psychological perception of the face over different periods of time (5, 10 and 30 minutes). The ability to remember a face decreases significantly the more time elapses between exhibition of the face and the request to identify and recognize it at a later stage. The eyes, mouth, nose and facial shape are the elements most cited as facial identifiers. Regardless of their age, women are more assertive in the identification and recognition of faces, but especially in the 45-65 age group.

The effect of facial deformation

There is a pattern of construction of facial expression associated with each basic emotion, as discovered by recent research into the effect of facial deformation in the psychological perception of the basic emotions (Freitas-Magalhães, 2009d). The research procedure consisted in the identification and recognition of the basic emotions (joy, sadness, surprise, fear, anger, disgust and contempt) via the exhibition of purposely deformed faces extracted from F-M Portuguese Face (F-MPF), a database compiled by this author in 2003 and spanning ages ranging from 18 to 80 years. Degree of assertiveness in the identification and recognition of the facial expression of emotion diminishes as movement decreases and deformity increases. Sadness and contempt, two emotions which require little muscular movement when the subject of purposeful deformation, are the emotions which register the lowest identification and recognition ratings. Joy, anger, disgust, fear and surprise were more assertively perceived, and in the order given. Regardless of their age, women are more assertive in the identification and recognition of the basic emotions in deformed faces, especially in the 45-65 age group.

The effect of tears

Research into the psychophysiology of weeping and the effect of tears on emotional experience has found that women on average cry two or three times a week, and more frequently show their tears than men (e.g. Freitas-Magalhães, 2008a). The procedure consisted in the gathering of information (via questionnaire) on the frequency and intensity of weeping and the emotional and physical circumstances in which weeping occurs. The findings suggest that while women cry more than men, the latter cry more intensely when they do. Age differences were observed in the manifestation of tears: women in the 18-30 and over-60 age groups cry more frequently, but more intensely in the 35-55 age group. With men, weeping is more common in the 18-30 and over-60 age groups, but more intense in the 35-50 age group. Women tend to cry in their bedrooms and with their female friends, while men claim not to choose the location and place the emphasis on the circumstances which incite their tears. Both sexes are in agreement with regard to the reactive nature of tears, i.e. weeping is provoked by external factors; however, women also noted that sometimes they cry without knowing why. The death of kin, family breakups, loss of employment and the detection/treatment of illness are the most important causes for the production and manifestation of tears. The findings also indicate that women have (or claim to have) no shame about crying in public, while men are more withdrawn and only cry in public in exceptional circumstances. Both sexes see weeping as a reactive mechanism, a compensatory phenomenon which offsets the tribulations of life.

Facial symmetry

The classification of faces as "more masculine" or "more feminine" depends on the degree of symmetry they present, a phenomenon related with the mechanisms of attraction. According to research, symmetry is related to biological processes, where it functions as an indicator of attraction and the genetic suitability of a prospective partner. According to the findings of research into facial expressions and the recognition of the basic emotions, women can more readily and more consistently identify the basic emotions via facial expression - a faculty they retain over the course of their lives. Research involved individuals aged from 18 to 70. Joy, anger, sadness, surprise, disgust and fear were the emotions studied. In women the standard for the perception of the basic emotion of joy is in the 18-25, 40-50 and 60-70 age groups. Women perceive this emotion more spontaneously, frequently and rapidly than men. No homogeneous pattern can be identified for men, although anger and disgust are the emotions they identify most frequently and rapidly. Research revealed that men in the 60-70 age group identify sadness and fear more frequently and spontaneously. Women in the 18-25 age group perceive joy and sadness more frequently and spontaneously, while men more readily identify anger and rejection. Men in the 40-50 age group perceive sadness and surprise more frequently and spontaneously, while women more readily identify joy. While women frequently and spontaneously identify all the emotions, regardless of the age or gender of the individual exhibiting them, men more frequently and spontaneously identify the emotions exhibited by females. Perceptions are not linear across all age groups: the 60-70 age group had difficulty in correctly identifying the emotions expressed. The Micro Expression Training Tool (METT) and the Subtle Expression Training Tool (SETT), devised by Ekman in 2003, were the instruments used in the collection of empirical data. The facial expression of emotion was exhibited for only one quarter of a second, with participants subsequently asked to identify the emotion exhibited.

Expression and twins

The smile and its effect on the psychological perception of twins (Freitas-Magalhães, 2005). The objective of this research was to determine whether, controlling the face variable by the presentation of twins, people are perceived differently because of their gender. The broad smile was the smile type which exerts most influence on the psychological perception of the person, followed by the superior smile, closed smile and neutral expression. A gender effect is also observed in the comparison of smiles in twins: women identify more with a smile by the female twin, while men make no distinction.

Perception of facial expression in babies

Women are more spontaneous and consistent than men in the perception of the basic emotions conveyed by the facial expressions of babies aged one year, as research into the facial expressions and the recognition of emotions has shown. Joy, anger, sadness, surprise, disgust and fear were the basic emotions studied. The findings merely confirm that the identification by women of the basic emotions is the result of bonding interaction from the first three months of life, intensifying from 8 months without gender distinction. Men are less spontaneous and less consistent in their identification, manifesting errors of emotional perception in babies of both sexes between five and six months of age. Women are also better able to spontaneously identify positive emotions than negative emotions (e.g., Freitas-Magalhães, 2009b; Freitas-Magalhães & Castro, 2010c). Gestational age is a moderating variable in emotional perception. The 18-35 age group registers the least discrepancies in emotional perception, regardless of gender, while the 35-50 age group exhibits alterations, inaccuracies and errors in its emotional perceptions, a phenomenon especially marked in men.

X. TRUTH AND FALSEHOOD IN FACIAL EXPRESSION

Expressing and reading the emotions on the human face are two verbs which should be conjugated in the present, as they contribute to healthy interaction. Expressions are not merely signals - they are also freighted with emotional content. Persons who are blind from birth never change their facial expression. Learning seems to have little influence. Observation of the expression of the emitter presupposes that the receiver gets it immediately. Inhibition, via intentional muscular configuration, is performed consciously. The literature shows that individuals unable to imitate facial expressions after cerebral stimulation are unable to identify and recognize them to the same extent as those able to imitate are. Facial expressions can be false, and this falsity can be detected. When we express an emotion we are creating that emotion, so when we attempt to fake an emotion we fall prey to emotional conflict due to overlapping emotions. This process involves the secondary motor cortex (responsible for the alternative expression), the upper temporal sulcus (responsible for evaluating the effect of the forced expression) and the orbitofrontal cortex (responsible for inhibiting the natural expression). When we attempt to display an emotion which we do not feel, diverse cerebral structures are involved. With true expressions, the left hemisphere controls movement on the right side of the face, while the right hemisphere, more emotional, controls the left side. Take for example the eyes and the importance of their movement. The eyes can be a major giveaway in lie detection, and women are more assertive in this procedure, according to the conclusions of research into the effect of the eyes in lie detection (Freitas-Magalhães, 2009e). The procedure consisted in the identification and recognition of falsehood via true and false stories with which a certain look was associated (direct, evasive, objective, right, left, straight ahead, profile, miosis, mydriasis, normal, upwards, downwards, level). The standard for identification of falsehood was the more frequent exhibition, in this order, of intensity (mydriasis and miosis), incidence (averting the eyes), inclination (up, down) and laterality (profile). Regardless of their age, women are more assertive in the identification and recognition of falsehood, especially in the 25-45 age group. Research has also shown variations in the types of look associated with falsehood from 45 years of age onwards.

XI. PSYCHOSOCIAL IMPLICATIONS AND APPLICATIONS

The facial expression of emotion has diverse psychosocial implications and applications (Freitas-Magalhães, 2008b; Freitas-Magalhães & Castro, 2007, 2008bc; Santos, Freitas-Magalhães & Castro, 2010ab). In the fields of healthcare and justice, for example. In healthcare, the applications are in physiognomy and pathognomony, i.e. verification that the patient is transmitting a true emotion. Subtle expressions and microexpressions in the context of clinical supervision. Emotional expressiveness as an indicator of psychological state and social cooperation. The study of pain via detailed mapping of facial expressions (Simon, Craig, Miltner & Rainville, 2006).  Some current lines of research are examining pain in terms of its facial manifestations. Identifying and recognizing the neuroanatomical features of the expression of pain facilitate productive interaction between patients and doctors in healthcare settings (e.g., Simon, Craig, Miltner & Rainville, 2006). Mapping the features of pain allows us to immediately detect discomfort and to take more assertive action, since the face is like a fingerprint of suffering. The neurophysiological mechanisms of pain give us valuable information about the face and its ability to convey the state of health of an individual, and this information is of great value in the prevention and treatment of pain. Meanwhile, technology is also making its contribution to the study of the human face, with attention focussing on sufferers of e.g. Alzheimer's and Parkinson's diseases. The objective here is to allow suffers of degenerative diseases of the brain to improve their ability to identify and recognize faces, thus improving their quality of life. Memory loss is the principal symptom of such diseases as Alzheimer's, so the challenge is to create signals which assist memory, and the human face is a reactive mechanism which can play a decisive role in this process. As for Parkinson's disease, the strategy is to give patients the chance to identify and recognize faces with the objective of facilitating interaction via the mapping of facial movements. Loss of the expressive faculties is a recurrent symptom of this disease, so the challenge is to create signals which assist memory, and again the human face is a reactive mechanism which can play a decisive role in this process. All aspects of the expressive powers of sufferers of Parkinson's disease are worthy of scientific analysis, for knowledge of the facial movements is a valuable asset in the development of a healthy society, as it clarifies the mechanisms of communicative interaction. In addition to 4-dimensional imaging technology for the verification and evaluation of the muscular movements, other techniques can be used for scientifically verifying the functionality of facial expression in sufferers of Parkinson's disease (McCabe, D., Borod, J., Meltzer, E., Spielman & Ramig, L. 2010).

The smile and its therapeutic effects

The literature (e.g., Freitas-Magalhães & Castro, 2009g) confirms that the broad smile and superior smile are the two types of smile which exert the greatest therapeutic effect. The effect of these two types of smile is more frequent and more intense in women than in men. It was also observed that the therapeutic effect of the smile varies according to age group: members of the 45-60 age group registered clear improvement in their mental health in relation to the 25-44 age group, and participants attached increasing importance to positive thoughts when exposed to broad and superior smiles.

Forensic psychology: The value of facial expressions

The adoption of methods and techniques for the analysis of the facial expression of emotion within the legal system. Analysis of the effect of the smile in lie detection represents one more attempt to raise awareness in legal circles of the need to adopt scientific procedures for the analysis of the facial expression of emotion. The lines of research have shown that the legal system stands only to gain by using facial expression analysis techniques. One example is questioning by police and legal representatives, during which the use of scientific methods for interpreting facial movements and facial language can be decisive in determining the truth, and one more contribution, therefore, to the body of evidence. Like DNA analysis, the science of the human face also employs the concept of markers of trust in analysis of facial expressions. Training police agents to detect emotional incongruities using scientifically-proven techniques and methods is one potential application. The "autopsy" of facial expressions could prove decisive in solving certain crimes, as some muscular movements are totally involuntary and as such escape the control of an individual who might, during questioning, attempt to conceal them. The face is a laboratory of scientific analysis which could be put to the service, in this case, of justice.

Emotion and psychopathy

Research has examined the relationship between psychopathy and the emotions (e.g., (Willmott, Casey, Rogers & Yiend, 2009). The objective is to understand the cerebral processes involved in the neuropsychophysiological reactions of the facial expression of emotion and to establish a standard which facilitates treatment and the prevention of crime. The ability to identify a psychopathic state is a vital predictor for treatment and the prevention of violence. Science has suggested that psychopaths process emotions in a different way from normal persons, and therefore the manifestation of emotions in the form of facial expressions is likely to be different too. The ability to identify and recognize emotions and the frequency of their manifestation could form the basis for the creation of a database for forensic use. To verify and analyse the brains of psychopaths and the relationship with facial expression, research laboratories use functional magnetic resonance imaging (fMRI), neurofunctional psychometry and computer programs which stimulate the cerebral systems, especially the limbic system.

XII. CONCLUSION

Debate on the facial expression of emotion continues to revolve around the questions of universality and cultural specificity (Freitas-Magalhães, in press). This involves determining whether expressions of emotion really are expressions, and the emotions are not an easy subject to study. Research continues. The different aspects of facial expression are universal or culturally specific. The facial expression of emotion is a complex and multidisciplinary domain which requires, after verification of the structural and functional axes, refinement of analysis methods and techniques. Computer programs will play a decisive role in the future, as the science of facial expressions finds more and more applications in a range of psychosocial contexts (Freitas-Magalhães & Castro, 2009hi). The emotions play essential roles in human development. For example, they prepare individuals for action and help mould behaviour. The emotions are a mechanism of social interaction, promoting development in the scope of the neurocultural theory advanced by Ekman (Freitas-Magalhães, 2009f). No one will dispute that the human face is a rich repository of information and communication. However, analysing the face is not as easy as it might sometimes appear. Superficial analysis of the face leads us into error, and this error can become a serious one in cases where the information emitted is incorrectly assimilated and interpreted - or where the information in question is actually false. Interpreting the signals put out by the human face is a line of research which has occupied many scientists in the last two decades. But what's the ultimate objective of this research? To answer this question, we have to identify and understand the psychological states which underlie the facial expressions, however these expressions are configured. The codification of such work is the next step in the construction of a theoretical groundwork for the development of a reliable and workable scientific technique for the mapping of the human face. In psychology, the study of the human face is now a wide-ranging field which occupies large numbers of researchers. Review of the literature is vital given the countless studies carried out and their greater or lesser practical feasibility. The study of the face, insofar as it is a measurable and quantifiable phenomenon, is now a vital condition for research in the domain of the facial expression of emotion. In early studies, the face was seen, and studied, as an independent variable. The objective was simply to study the effect of the face on other associated variables. Nowadays, however, the face is seen and studied as a dependent variable in its relationship with other variables in the context of human systems of communication. From situations of social confrontation (e.g. embarrassment) to the study of facial expressions in forensic, healthcare, school etc. contexts, the face is a constantly-changing repository of information which requires refined theoretical and practical analysis if the scientific interpretation of it is to be put at the service of society at large. Over the course of history, basic research on the emotions has involved the analysis of emotional experience, the neurological control centres of facial expression and the difference between voluntary and involuntary expression. Meanwhile, applied research has shown how useful it can be to identify and recognize movements of expression and has pointed to the social implications of such knowledge - for the brain, not the face, is the actor.

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Freitas-Magalhães, A., & Castro, E. (2009d, September). The effect of pride on emotional experience. Empirical study with Portuguese. Paper presented at the 23rd Annual Conference of the European Health Psychology Society, Pisa, Italy.

Freitas-Magalhães, A., & Castro, E. (2009e, September). Facial expression: The effect of smile in the psychological perception of delinquents. Paper presented at the 19th Conference of the European Association of Psychology and Law, Sorrento, Italy.

Freitas-Magalhães, A., & Castro, E. (2009f). The neuropychophysiology construction of the human smile. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 1, pp. 3-22). Porto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2009g). Facial expression: The effect of the smile in the treatment of depression. Empirical study with Portuguese subjects. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 1, pp. 129-140). Oporto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2009h). Facial expression: The recognition of basic emotions in heroin addicts. Empirical study with Portuguese subjects . In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 1, pp.159-166). Oporto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2009i). Facial expression: The recognition of basic emotions in cocaine addicts. Empirical study with Portuguese subjects. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 1, pp. 251-258). Oporto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2010a). Fear perception scale: First study of development and validation among the Portuguese population. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 2, pp. 67-81). Oporto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2010b). Facial expression: The reciprocation of the smile in social interaction. Empirical study with Portuguese subjects. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 2, pp. 135-144). Oporto: University Fernando Pessoa Press.

Freitas-Magalhães, A., & Castro, E. (2010c, February). Facial expression: The recognition of basic emotions happiness and anger. Empirical study with Portuguese babies of aged between 04 and 08 months. Paper presented at the 38th Annual International Neuropsychological Society Meeting, Acapulo, Mexico.

Freitas-Magalhães, A., & Castro, E. (2010d, May). Facial expression: The recognition of fear in alcohol dependents. Empirical study with Portuguese subjects. Paper presented at the 22nd APS Annual Convention - Revolutionary Science, Boston, USA.

Freitas-Magalhães, A., & Castro, E. (2010e, August). Facial expression: The recognition of the basic emotions on mentally disabled. Empirical study with Portuguese. Paper presented at the 2010 Annual APA Convention, San Diego, California, USA.

Freitas-Magalhães, A., & Castro, E. (2010f, September). Facial expression: The recognition of sadness in alcohol dependents. Empirical study with Portuguese subjects. Paper presented at the 24th European Health Psychology Conference - Health in Context, Cluj-Napoca, Romania.

Freitas-Magalhães, A., & Castro, E. (2010g, November). The neuropsychophysiology of emotional facial expression: The identification and recognition of anger in alcohol dependents. Empirical study with Portuguese subjects. Paper presented at the Sixth World Conference on the Promotion of Mental Health and Prevention of Mental and Behavioral Disorders, Washington, DC, USA..

Freitas-Magalhães, A., & Castro, E. (2011, July). The influence of the musical notes in recognition and representation of the basic emotions. Empirical study with Portuguese children. Paper presented at the 12th European Congress of Psychology (ECP), Istanbul, Turkey.

Freitas-Magalhães, A., & Neto, F. (2003, September). Smile expressiveness: Gender differences in Portuguese academic youths. Paper presented at the Xth European Conference on Facial Expression, Measurement and Meaning, University of Bologna, Rimini, Italy.

Freitas-Magalhães, A., Castro, E., Baptista, J., & Santos, C. (2010, July). The psychophysiology of emotional facial expression. Symposium presented at the 27th International Congress of Applied Psychology (ICAP 2010), Melbourne, Australia.

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Santos, C., Freitas-Magalhães, A., & Castro, E. (2010b). Emotional literacy in health services: Functions, applications and implications. In A. Freitas-Magalhães (Ed.), Emotional expression: The brain and the face (Vol. 2, pp. 285-299). Oporto: University Fernando Pessoa Press.

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About the author

A. Freitas-Magalhães, Ph.D., is a Professor of Psychology at University Fernando Pessoa Health Sciences School. He is also the founder and Director of Facial Emotion Expression Lab (FEELab), Editor-in-Chief of the Journal of Brain, Face and Emotion and a member of the American Psychological Association (APA), International Neuropsychological Society (INS), International Brain Research Organization (IBRO), Association for Psychological Science (APS) and the International Society for Research on Emotion (ISRE). Freitas-Magalhães was born in Fornelos, Portugal.

http://freitas-magalhaes.com