Expression in the Face, Posture and Voice

Historical Importance of Facial Expression Research

The study of facial expressions, especially as it relates to emotions, has deep roots in evolutionary theory and psychology. Early work by Charles Darwin on facial and postural expressions established the foundation for the belief that emotions and their expressions are biologically innate rather than learned through cultural practices. Darwin noted the similarity between human facial expressions and those of other species, suggesting that expressions of emotion, such as fear or anger, evolved to serve survival functions.

Paul Ekman and Carroll Izard's Studies:
Ekman and Izard further developed Darwin's theories by studying the universality of emotional expressions. They proposed that facial expressions of basic emotions are innate and universally recognizable, irrespective of culture. Their research, particularly Ekman’s New Guinea study, aimed to test the universality of expressions by studying people with minimal exposure to Western culture. Ekman’s method involved showing indigenous participants photographs of faces depicting various emotions and asking them to match these with emotionally charged stories. The results indicated a remarkably high recognition of emotions such as happiness, anger, disgust, fear, and sadness (ranging from 79%-92%).

New Guinea Study:
In New Guinea, despite cultural and language barriers, Ekman’s participants accurately identified emotions depicted through facial expressions at high rates. For example, 92% of participants recognized happiness, and 84% identified anger. However, the study was not without limitations: translators could not always accurately convey the stories, and the participants may have selected the closest facial expression available rather than the perfect match.

Facial Action Coding System (FACS):
Ekman developed the FACS, a tool used to identify and categorize facial movements that correspond to different emotions. This system categorizes facial muscles into “action units,” allowing researchers to systematically study facial expressions and link them to specific emotions.

Expression and Emotion in Posture and Voice:
Research by Aviezer and colleagues has suggested that body posture can sometimes be more important than facial expressions in conveying emotional information. For instance, when shown a tennis player’s posture after scoring a point, participants could determine whether the player won or lost based solely on body posture, even without seeing the player’s face. Postures of victory or defeat seem to communicate emotional states more strongly than facial expressions in certain contexts.

The concept of “vocal bursts”—short, involuntary vocal expressions like "Ah!" or "Mmm!"—also plays a significant role in nonverbal emotional communication. Studies showed that emotions such as anger, disgust, and surprise were recognized with high accuracy in vocal bursts, while others, like love and pride, were harder to distinguish.

Cross-Cultural Studies of Facial Expressions:
Ekman expanded his studies globally, gathering evidence across multiple cultures, including in countries like Japan, Greece, and Turkey. The results suggested that facial expressions associated with basic emotions (happiness, anger, fear, sadness, disgust, and surprise) were widely recognized across cultures, providing further evidence for the universality of these expressions.

Cultural Display Rules and Gender Differences:
While certain expressions are universal, cultural norms—known as “display rules”—govern when and how emotions are shown. For instance, in some cultures, expressions of anger or sadness may be suppressed in public. Gender differences also influence emotional expressions. Men may be more inclined to display anger, while women may express sadness or smile more frequently. These differences are often linked to societal power dynamics and gender norms.

Meta-Analysis and Expression Dialects:
In a meta-analysis of studies on vocal expressions, researchers found that emotions were generally recognized across cultures, though with some variation. The concept of “expression dialects” was introduced to explain how people from different cultures may use different facial expressions for the same emotion. These dialects are analogous to language accents—different, but understandable within a cultural group.

Nonverbal Expression and Emotional Feelings:
The facial feedback hypothesis posits that facial expressions can influence emotional experiences. For instance, smiling can make people feel happier, even if the smile is forced. However, research on this hypothesis has been mixed, with some studies showing effects on emotional experiences and others failing to replicate these findings.

Power Pose Hypothesis:
Studies on body posture also suggest that adopting expansive, powerful postures (e.g., standing tall) may lead to feelings of increased power and confidence. This has been shown to correlate with higher self-assessment of performance and positive mood. However, these effects on physiological markers such as testosterone and cortisol levels have not been consistently replicated in larger studies.

Theories of Emotion and Nonverbal Communication:
Several modern theories of emotion have emerged to explain how nonverbal expressions are connected to emotions:

  1. Basic/Discrete Emotions Theory: Suggests that emotions are innate and each emotion has a specific, recognizable facial expression.

  2. Component Process Model: Focuses on how emotions arise from cognitive appraisals of situations and how facial expressions reflect these appraisals.

  3. Core Affect/Psychological Construction: Emphasizes that facial expressions communicate a combination of valence (positive or negative) and arousal, which are reliable across cultures.

In conclusion, research on facial expression, posture, and vocalization has established a nuanced understanding of nonverbal communication. While there is substantial evidence supporting the universality of basic emotional expressions, there are also significant cultural influences, with different cultures using "expression dialects" and display rules to shape how emotions are expressed and perceived. These insights help us understand not only the biological basis of emotional expressions but also the complex interaction between biology, culture, and context.