Читать книгу The Handbook of Solitude - Группа авторов - Страница 30

An additional line of our research has been to examine the neural substrates of different subtypes of shyness in children that are presumed to have different adaptive functions. As mentioned earlier in the first section, we have been particularly interested in different subtypes of shyness that share conceptual overlap, such as fearful/nonpositive shyness and self‐conscious/positive shyness, as they appear to have different adaptive functions. We have recently explored each of these two different conceptualizations of shyness in two separate studies to determine whether we could distinguish them on resting brain‐based measures.

In Study 1, we classified children with early‐developing (fearful) shyness and a later‐developing (self‐conscious) shyness. We found that children with later‐developing shyness had the highest relative salivary cortisol response (a measure of stress reactivity; Schulkin et al., 2005) in the context of self‐presentation, the highest levels of embarrassment, and the lowest social skills according to parent‐ and teacher‐report, whereas children with early‐developing shyness displayed the highest relative resting right frontal brain asymmetry (a neural correlate of fear and avoidance) relative to the other groups (Poole & Schmidt, 2019c). In line with Buss’ (1986a,b) hypotheses, this provides partial support that early‐developing shyness may be maintained by a sensitivity toward experiencing fear, whereas later‐developing shyness may be more closely related to self‐conscious emotions.

In Study 2, we examined resting state EEG measures in children with positive shyness, nonpositive shyness, and low overall shyness. We operationalized positive shyness as the display of shy behavior (e.g., avoidance) and positive affect (e.g., smiling), whereas nonpositive shyness is the display of shy behavior without positive affect (Poole & Schmidt, 2019a, 2020a). As mentioned above, positive shyness has been regarded as an adaptive, approach‐dominant subtype of shyness (see Poole & Schmidt, 2020b, for a recent review).

Similar to Study 1, we first examined resting state frontal EEG asymmetry among children classified as positive shy, nonpositive shy, and low shy (Poole & Schmidt, 2020a). Our results revealed that children classified as nonpositive shy displayed greater relative resting right frontal EEG activity, whereas children classified as positive shy and low shy displayed greater relative resting left frontal EEG activity (a neural correlate of approach). These findings converge with studies that have examined psychosocial correlates of approach‐avoidance in these subtypes, extending this work to a neural measure. It may be the case that children who display more positive shyness exhibit an underlying biological diathesis for approach as reflected by greater relative left frontal brain activity at rest, which could facilitate approach behaviors in social situations and yield the benefits of such social interactions, including social engagement and competence.

In Study 2, we also examined frontal EEG delta‐beta correlation among these shyness subtypes (Poole & Schmidt, 2020a). Delta‐beta correlation is thought to reflect the efforts of regulatory networks to down regulate arousal in the subcortical networks (Knyazev & Slobodskaya, 2003; Schutter & Knyazev, 2012) and thus some researchers have conceptualized delta‐beta correlation as a proxy for adaptive emotion regulatory abilities. Our results revealed a relatively higher frontal delta‐beta correlation among the positive shy children compared to the nonpositive shy and low shy children (Poole & Schmidt, 2020a). As stated above, positive shyness is hypothesized to emerge from the simultaneous feelings of arousal and regulation in social situations (Colonnesi et al., 2014; Colonnesi et al., 2017; Nikolić et al., 2016; Poole & Schmidt, 2019a), and thus it is possible that the positive shy children display greater synchrony of delta and beta oscillations as reflected by stronger delta‐beta correlation due to their efforts to regulate feelings of arousal.