Analysis: facial expressions allow us to observe from the outside the possible internal states experienced by those around us

Humans are highly social animals that communicate by giving and receiving signals to and from one another. These signals are the building blocks of our relationships, from which social bonds are made or broken. Our interdependent nature has influenced how evolution has prepared us for a social world because an instruction is coded in our genes to pay attention to the most informative part of another's body: the face.

Even before they have had time to learn about the importance of faces, newborn infants show a preference for a particular face-like visual pattern. Compared with other possible arrangements, infants prefer to look at a pattern of three dots when they are presented in a triangular arrangement with two dots above and one below. This pattern resembles closely the key features of the eyes and nose within a face. A genetically inherited preference for such a pattern means that our attention is automatically captured by the faces around us from infancy, which in turn allows us to learn from the social signals they express.

Facial expressions allow us to observe from the outside the possible internal states experienced by those around us. The sensation of internal signals in the body, a process called interoception, provides us with information about our emotional state. For instance, feeling your heart palpitate and stomach somersault might indicate that you are experiencing love, or perhaps fear.

How can two such opposite emotions share similar bodily signals? While there is no theory all scientists agree on, Lisa Feldman Barrett's 'theory of constructed emotions' offers one interpretation. She suggests that we learn to apply emotional labels to the combination of signals from inside our bodies and from the world around us while also considering what goal we are trying to achieve.

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From Freedom In Thought, this is why you feel the way you feel

So, the rhythm of your heartbeat in isolation is insufficient to distinguish between love and fear. This contextual and complex way in which we understand our own emotions means our culture and past experiences influence how we interpret what we feel. In social situations, we often have access to the same external information as others, but we can never sense directly what they feel inside. Facial expressions provide us with an indirect route to understanding others' emotions.

To study emotional expressions, psychologists have categorized all the possible individual muscle movements of the face into Action Units. Emotional expressions can therefore be described as the combination, duration and intensity of these units. For example, sadness can be expressed as the combination of Inner Brow Raiser (AU1), Brow Lowerer (AU4), and Lip Corner Depressor (AU15). Such categorization has many uses. For instance, it allows us to study how emotional expressions vary across cultures, and it is used by animators to create computer generated expressions in their characters.

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From RTÉ 2fm's Dave Fanning Show in 2009, the late author Lillian Bridges on face reading and diagnosis

But humans are complex creatures and what is displayed on a face is not always a faithful readout of the underlying emotion. Humans can consciously compose the right combination of Action Units to display to others an emotion they may not actually be experiencing. Indeed, social norms encourage us to regulate our emotional expressions to act appropriately. The existence of idioms, such as 'to put on a brave face’, indicates a social awareness of an ability to disassociate what we feel on the inside from what we show on the outside.

Emotional expressions pose a peculiar problem. They are important stimuli in our social environments to which our attention is drawn spontaneously, yet they are sometimes misleading. The motivation to resolve the ambiguity of emotional expressions is often revealed through the creation and discussion of works of art. While discourse on how both human and non-human animals similarly express facial emotions goes back to Darwin, the capacity to consciously and verbally reflect on emotions and artistically represent them is certainly uniquely human.

Cellar Door by Catherine Fleming

The Westend Art Collective in Galway demonstrates this distinctly human ability for conscious reflection on our own minds, an ability psychologists call ‘metacognition’. In her artwork Cellar Door, Catherine Fleming paints with an intuitive instinct for the psychological factors at play when we read others’ emotions. In viewing this figure, our genetically inherited bias towards face-like patterns cues our attention to the face, however, instead of being met with its usual features, in their place are surrealist images of the ocean and a dark stairwell.

Her words about the work illustrate the dissociation of emotions as expressed verses as felt. "This piece explores how, despite whatever face one shows to the world, what lies beneath could be entirely different. I have found that people can train themselves to hide how they actually feel and put on a brave face, manipulating how others around them perceive them. This is why instead of an actual face I have painting this scene of the descent into a cellar where their true feelings are stored."

Without a face or when faces are unreliable, how can we read others’ emotions? In Fleming's work "the hands are highlighted to signify how often body language can signal one’s true feelings more clearly than a face can. Tension and anxiety are often expressed particularly through one’s hands." Ultimately, the challenge of interpreting emotional expressions can be both an art and a science yet elude both.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ