survival throughout evolution.
Fearful and Self‐Conscious Shyness
Shyness has been described as a social ambivalence in which both approach and avoidance motivations are experienced simultaneously and in conflict (Asendorpf, 1990; Coplan et al., 2004; Lewis, 2001). However, the degree to which each of these motivations is experienced varies across individuals. There is empirical support for heterogeneity within shyness and shy expressions across a range of measures in toddlers (Eggum‐Wilkens et al., 2015), young children (Poole & Schmidt, 2019c, discussed further later in the chapter), and adults (Bruch et al., 1986; Santesso et al., 2006; Schmidt & Robinson, 1992). For example, individuals who experience heightened avoidance motivations within this motivational conflict are thought to possess an evolutionarily older phenotype known as fearful shyness, which tends to emerge relatively early in human development. This type of shyness reflects a heightened sensitivity to social threat and emerges with the onset of stranger fear (i.e., 6–12 months of age; Buss, 1986a,b). Fearful shyness appears to have evolved from a basic fear system to protect individuals from possible physical harm by unfamiliar conspecifics (Schmidt & Poole, 2019). In support of this subtype, there is evidence for a high degree of individual variation in fear responses in mammals (Boissy, 1995), and this variation is evident early in life and is associated with different physiological and behavioral correlates (see Schmidt & Schulkin, 1999, for a review). In all, fearful shyness reflects a dominating motivation for an avoidance reaction to social stimuli and can be seen as a temperamental disposition that is evident from infancy.
In contrast, self‐conscious shyness reflects a motivation for both approach and avoidance, is expressed later in development (Buss, 1986a,b), and is assumed to have evolved later in human history (Schmidt & Poole, 2019). This type of shyness has been thought to emerge with the evolution of self‐awareness and other‐understanding. As such, self‐conscious shyness does not develop in human children until the preschool years at which time self‐awareness is evident (Schmidt & Poole, 2019) and children can take on the perspectives of others (e.g., Wellman & Liu, 2004). Self‐conscious shyness has been found to be unrelated to fearful shyness (Eggum‐Wilkens et al., 2015) as it is associated with less fear of physical harm and more fear of negative social evaluation, threat to the ego, and social rejection or exclusion (Schmidt & Poole, 2019). This shyness subtype may have evolved in line with selective pressure for behaviors that aid in securing strong human relationships for the purposes of protection, support, and access to reproductive opportunities (Buss, 1999; Gilbert, 1989). Since failure to gain access to these important social resources can result in rejection and loss of social status, preoccupation with self‐generated behaviors in the form of self‐conscious shyness can be seen as a method for monitoring an individual’s impression on social conspecifics (Gilbert, 2001).
Fearful and self‐conscious shyness can be evaluated in humans by monitoring facial expressions during avoidance behaviors, such as gaze and head aversions (Asendorpf, 1990). In particular, nonpositive shyness, which occurs when an avoidant behavior is exhibited during a neutral or negative facial expression, largely expresses fear and discomfort rather than pleasure (Asendorpf, 1989; Colonnesi et al., 2014). Although not all nonpositive expressions of shyness are inherently fearful, this shyness subtype is conceptually linked to fearful shyness (e.g., Schmidt & Poole, 2019). In contrast, positive shyness, which is evident when a smile is present before or during an avoidant behavior, suggests a motivation for both approach and avoidance (Reddy, 2005; Thompson & Calkins, 1996). This expression of shyness has been commonly referred to as a “coy smile,” which involves the highest level of arousal in the smile being immediately followed by a gaze or head aversion (see Colonnesi et al., 2013; Nikolic et al., 2016). Although self‐consciousness is not always displayed in a positive manner, positive shyness is conceptually linked to self‐conscious shyness (e.g., Schmidt & Poole, 2019).
In general, self‐conscious shyness may lead to positive facial expressions during shy episodes, which can have many adaptive consequences within social interactions. In contrast, fearful shyness may generally lead to nonpositive (i.e., negative and sometimes neutral) facial expressions during shy episodes, which do not grant the same benefits. It is important to note that these shyness subtypes are not mutually exclusive within individuals. Some people may exhibit high or low levels of both self‐conscious shyness and fearful shyness (i.e., high levels of positive and nonpositive shyness, respectively) or higher levels of one or the other. For the remainder of the chapter, there are times when we use fearful shyness interchangeably with nonpositive shyness, and self‐conscious shyness interchangeably with positive shyness. As we discuss later in the chapter, part of our research program has been directed toward attempting to distinguish among these multiple subtypes and uses on a conceptual and biological level.
Adaptive Aspects of Shyness Subtypes
We argue that self‐conscious shyness may be currently more adaptive than fearful shyness, but this claim of course depends on the context in which it is expressed. Although there appear to be adaptive functions to both shyness subtypes, fearful shyness was likely useful in our evolutionary past when unfamiliar social conspecifics were considered physically dangerous. In contrast, self‐conscious shyness appears to be more salient in our current social environment as the nature of our social interactions have become more complex. It is also possible that fearful shyness serves an adaptive function in current human history, such as in the case of “stranger danger”, and that high levels of self‐consciousness could critically deter an individual from successfully engaging in social interaction. However, we argue that moderate to low levels of self‐conscious shyness are more adaptive in most current social situations when compared to fearful shyness and characteristics of extreme self‐consciousness.
For example, the Emotional Reactivity Hypothesis (ERH) states that less fearful temperaments better allow for the evolution of more sophisticated social processing and understanding. This hypothesis has been explored in canines (Hare, 2007; Hare & Tomasello, 2005) and children (LaBounty et al., 2017; Lane et al., 2013; Wellman et al., 2011) and pertains to social cognition: one of many traits known to increase social sophistication in humans, primates, and other mammals (Hare, 2007). Social cognitive skills, such as Theory of Mind, allow individuals to make social judgments through inferring others' thoughts, feelings, and beliefs. Better Theory of Mind ability has been found to be positively related to positive shyness while there is evidence to suggest that nonpositive shyness is negatively related to this social cognitive skill (Colonnesi et al., 2017; MacGowan et al., 2021). These findings suggest that, over time, less fearful forms of shyness (i.e., positive shyness) may have been selected for as the complexity of human social systems increased. Another adaptive aspect of positive shyness is its potential to increase interpersonal liking and inspire affiliative and prosocial behaviors in others (Colonnesi et al., 2014; Keltner et al., 1997).
It has been argued that individuals who engage in higher levels of positive shyness are likely to gain self‐esteem from effectively dealing with social challenges and are presumed to learn more from social situations (Thompson & Calkins, 1996). As well, positive shyness among humans and other species may allow for additional time for the individual to learn about and reflect on a conspecific’s motives or intentions before acting and committing to approach‐ or avoidance‐related social behaviors (Schmidt & Poole, 2019). Interestingly, these coy behaviors have been documented in other species (McNamara et al., 2009) and are thought to signal interest while gaining more information regarding the social conspecifics that are present and the safety of the social environment (Candolin, 2003; Wachtmeister & Enquist, 1999).
Work examining positive shyness has also suggested that these expressions might act as an appeasement signal to potentially dominant or threatening social partners. In other primates with similar social systems, such as chimpanzees and macaques, teeth baring is thought to signal appeasement and affiliation to others (see Parr & Waller, 2006). In humans, some have viewed positive shyness as a placation behavior for real, imagined, or imminent social breaches (Keltner & Anderson, 2000; Keltner et al., 1997). Thus, positive expressions of shyness may allow for cautious and low‐risk interaction that involves simultaneous appeasement displays. Some shy behaviors