The Neuroscience of Smiling and Laughter

Pieter Rossouw


Published in The Neuropsychotherapist Issue #1


Why is it hard to smile when things are going wrong? Why can’t we laugh when we experience pain or distress? Why does a good laugh make us feel great? What is the neuroscience of smiling and laughter?

Social interactions are especially important to humans as they lead to the development of social skills (thereby promoting survival) and the facilitation of neural growth through increased neural activity (Nelson, 2008; Niedenthal, Mermillod, Maringer, & Hess, 2010). One of the key aspects of successful social interaction is using and communicating emotions to another party to inform them of one’s intentions and motivations (Szameitat et al., 2009). Although emotion can be communicated through the whole body (e.g., posture, movement), it is the face that is considered the most important tool that facilitates successful emotional communication in social interactions, as facial expressions have the ability to convey a diverse range of emotional and intentional states (Schilbach, Eickhoff, Mojzisch, & Vogeley, 2008).

Communicating emotions can influence the behaviour of another party in social interactions (Szameitat et al., 2009; Veronesi, 2009). For instance, research shows that human observers of all ages (beyond four months), races, and cultures have a tendency to automatically imitate the facial expressions and gestures of others (Schilbach et al., 2008; Szameitat, 2009; Warren et al., 2006). The term facial mimicry is applied to this phenomenon—the spontaneous and involuntary facial movements that occur in response to the observed facial expressions of a perceived other (Kühn et al., 2011; Schilbach et al., 2008). This mimicry extends beyond the motor regions of the brain that are responsible for muscle movements. It has been shown that facial mimicry triggers an internal (and often associated) emotional state in the observer by activating brain regions such as the cingulate cortex, the hippocampus and the dorsal midbrain (limbic system); for example, an observed smiling face would evoke happiness and a smile on the observer’s face (Schilbach et al., 2008). Both the mimicry and the resulting effect are considered to be the result of the involvement of mirror neurons: a corresponding neural network to the action that is either observed or mimicked by the observer (Carr, lacoboni, Dubeau, Mazziotta, & Lenzi, 2005). While a wide range of emotions can be conveyed using facial expressions, it is the smiling face that is considered to be the most rewarding to human and nonhuman primate observers (Pönkänen & Hietanen, 2012; Tsukiura & Cabeza, 2008). A smiling face can be interpreted as trustworthy, familiar, more attractive, and kind, as opposed to neutral or frowning/grimacing faces (O’Doherty et al., 2003; Winston, Strange, O’Doherty, & Dolan, 2002). Smiling faces also tend to activate areas of the brain such as the hippocampus and left frontal region while frowning/grimacing or threatening facial expressions are associated with right frontal and dorsal midbrain regions (Davidson, 2004; Tsukiura & Cabeza, 2008; Rossouw, 2012).

These activation patterns are associated with “approach-avoidance” motivation schema. If facial expressions convey positive emotions, such as a smile, then the observer may decide to approach the situation, and vice versa (Buss et al., 2003; Pönkänen & Hietanen, 2012). Approach-related brain activation leads to optimal neural functioning, with optimal levels of neurogenesis and neuroplasticity, whereas avoidance-related brain activation leads to protective responses such as the suppression of neurogenesis to limit the impact of stressful/negative stimuli on the brain (McEwen, 2009). As cognitive processing tends to be enhanced by reward, and neural activity benefits from predominantly “approach” motivational goals, it is not surprising that humans thrive in environments where most social interactions are based on positive emotion communication (Kühn et al., 2011; Warren et al., 2006). This is evident in research showing that superior leaders are those who are likely to facilitate opportunities for laughter in their workplace, with superior leaders creating three times more opportunities for laughter than non-superior leaders (Veronesi, 2009).

Laughter often occurs alongside smiling faces, as research indicates that facial mimicry activates the inferior part of the left precentral gyrus, a region associated with the perception of emotional vocalisation (e.g., laughter), and this activation likely occurs o prepare the observer for possible facial responses to the observed stimuli (Schilbach et al., 2008). Like facial mimicry, laughter is observed in all humans and nonhuman primates (Szameitat et al., 2009). More importantly, laughter is considered to promote “approach” motivational goals and attachment behaviour with potential for strong social bonding (Nelson, 2008). It seems that Provine (2000) was onto something: smiling and laughter are instinctual survival tools for humans that can help us thrive in our environment.



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