The Handbook of Solitude

Neural correlates of attentional shifting also have been shown to moderate the association between shyness or behavioral inhibition and socioemotional adjustment in much the same way. When individuals displayed neural correlates (e.g., N2 event–related potential response) associated with relatively strong attentional and cognitive control, shyness was positively associated with socioemotional maladjustment (e.g., Henderson, 2010; McDermott et al., 2009). This pattern of results suggests that different aspects of self‐regulation (i.e., inhibitory control and attentional shifting) may have different consequences for shy children across different domains of functioning (e.g., social adjustment, academic adjustment, psychopathology).

Our group has found a similar pattern of behavioral results using temperamental inhibitory control and attentional shifting to better understand the relation between shyness and observed social behavior in two different social laboratory contexts in a sample of preschoolers (Hassan et al., 2020). We were interested in children’s attempts at seeking social support from a relatively familiar experimenter during a frustration task where children were precluded from gaining access to a desirable toy. We also assessed children’s social engagement during a stranger approach task when a novel experimenter entered the room and attempted to engage with the child using a standardized script (Goldsmith et al., 1995). We found that attentional shifting, but not inhibitory control, moderated the association between shyness and social support seeking during the frustration task and social engagement during the stranger approach task. More specifically, we found shyness was only negatively associated with social support seeking and social engagement when individuals displayed relatively high levels of attentional shifting, and was unrelated to social behavior when individuals exhibited relatively low levels of attentional shifting.

These results provide support for the idea of heterogeneity in both self‐regulation and shyness. Although self‐regulation is often conceptualized as an adaptive characteristic, there may be individual differences in the adaptiveness of high levels of self‐regulation in fear‐based temperamental styles such as shyness (Eisenberg et al., 1995; Graziano et al., 2007; Gross & Munoz, 1995; Ponitz et al., 2009). Similarly, although shyness is often conceptualized as avoidance in novel social contexts, our results suggest that not all shy children display reluctance to engage in social situations, and some of this heterogeneity may depend on children’s temperamental self‐regulation (Kagan et al., 1987, 1988).

In addition to functioning as an important moderator between shyness and socioemotional outcomes, self‐regulation can also inform our understanding of different subtypes of shyness (e.g., positive and nonpositive expressions of shyness). As highlighted previously, individuals who display positive affect in conjunction with shy‐related behaviors (i.e., positive shyness) are thought to be distinct from individuals who display primarily negative or neutral affect in conjunction with shy‐related behaviors (i.e., nonpositive shyness).

In infancy, positive shyness has been most commonly identified through infants’ expressions of a coy smile (Colonnesi et al., 2013; Reddy, 2000). Behaviorally, coy smiles include the presence of a smile paired with gaze and/or head aversion that occurs before or during the decline of the peak of the smile (Colonnesi et al., 2013). In infants, coy smiles are most often observed in the presence of a stranger (Colonnesi et al., 2013) and the presence of positive and negative shyness (i.e., nonpositive shyness) continues to be distinguishable during toddlerhood (Colonnesi et al., 2014) and childhood (Poole & Schmidt, 2019a). As well, the degree to which children engage in each type of expression of shyness appears to be associated with different socioemotional outcomes. As highlighted previously, positive shyness is associated with more positive outcomes when compared to nonpositive expressions of shyness. In both toddlerhood and childhood, positive shyness is associated with more sociability and less anxiety, while nonpositive shyness is associated with less sociability, more social anxiety, and greater behavioral manifestations of fear during self‐presentation tasks (Colonnesi et al., 2014; Poole & Schmidt, 2019a). Taken together, these studies suggest that: (1) different subtypes of shyness are distinguishable as early as infancy; (2) children who display more positive shy expressions may experience reduced risk for socioemotional difficulties; and (3) children who engage in relatively high levels of positive shy expressions may be indistinguishable from non‐shy children in some respects (Poole & Schmidt, 2019a).

One proposed explanation for why these distinct subtypes of shyness are associated with different outcomes is self‐regulation. It has been suggested that displays of positive affect in conjunction with avoidance related behaviors may function to regulate an individual’s arousal levels in novel social situations such that displays of positive affect may allow for modulation of arousal while children remain oriented toward novel social stimuli (Colonnesi et al., 2014; Poole & Schmidt, 2019a; Sroufe & Waters, 1976). In support of this notion, Asendorpf (1990) noted that within a coy smile, gaze aversion tends to occur during the most communicative part of the smile, suggesting that the smile may act as a regulatory mechanism by modulating one’s internal milieu. Moving forward, it would be helpful to determine whether positive and nonpositive shyness are in fact differentially related to level of self‐regulation, and whether individual differences in temperamental self‐regulation influence the development and maintenance of positive and nonpositive expressions of shyness.

Taken one step further, it would be interesting to determine whether different aspects of self‐regulation (e.g., inhibitory control, attentional shifting) work to moderate the association between positive and nonpositive shyness and social behavior or clinical outcomes similarly to when shyness is treated as a homogenous construct. Finally, using evolutionary frameworks such as differential susceptibility to guide future studies and analyses may provide us with valuable information about the multiple contexts that may support adaptive functioning in both positive and nonpositive expressions of shyness (Belsky & Pluess, 2009; see also Schmidt & Miskovic, 2013).

Although the origins of shyness are multifaceted, interest in the neurobiological foundations of shyness has received considerable attention over the past several decades (see, e.g., Fox et al., 2001, 2005; Kagan et al., 1987, 1988; Schmidt & Schulkin, 1999, Schmidt & Miskovic, 2013, 2014, for reviews). This has been fostered by the availability of theoretical frameworks for understanding nonhuman animal and human brain‐behavior relations as well as advancements in technologies that have allowed for the relatively noninvasive collection of electrical brain activity such as electroencephalography (EEG). This combination has positioned researchers well to study the neural substrates underlying shyness, and how these neural processes may mediate adaptive and nonadaptive behaviors associated with shyness.

One of the most widely studied neural correlates of shyness and related phenomena is frontal brain EEG alpha asymmetry. This work is rooted in motivational models of frontal brain activation, which have described resting state frontal brain alpha asymmetry as a trait‐like measure (i.e., a biological diathesis) that is stable across time and context (see Coan & Allen, 2004; Davidson, 2000; Fox, 1991, 1994; Reznik & Allen, 2018, for reviews). According to this framework, greater relative activity in the left frontal brain region is presumed to facilitate approach‐related motivations and emotions such as sociability and happiness, whereas greater relative activity in the right frontal region has been implicated in avoidance‐related motivations and emotions such as shyness and fear (Reznik & Allen, 2018).