Brain development in shy children: Temperament, context, and anxiety

• In Event: 2-177 - The Unfolding of Brain and Behavior Within Affective and Social Development

Integrative Statement

Shyness is a ubiquitous phenomenon that reflects a pre-occupation with the self in response to real or imagined social situations associated with social inhibition and anxiety (Melchior & Cheek, 1990). Shyness is presumed to emerge from an approach-avoidance conflict (Asendorpf, 1990), resulting from an inability to regulate competing emotions of interest and fear (Schmidt & Buss, 2010). These emotion regulatory processes are dependent on activity in the frontal cortex (Posner & Rothbart, 2000). Previous work has suggested that delays in brain maturation, particularly in the frontal regions, may underlie a range of behavioral, emotion regulatory, and neuropsychiatric problems in children (e.g., Stuss & Knight, 2002). However, whether there are differences in frontal brain maturation associated with individual differences in temperamental shyness in children, the extent to which these frontal brain vulnerabilities confer risk for shy children, and in which contexts they manifest remain as empirical questions. Here we explored these questions in two separate studies.
In Study 1, using a prospective longitudinal study, we examined frontal brain maturation in 37 typically developing children across four separate lab visits. Shyness was measured at Time 1 (T1) using maternal report. We collected measures of resting regional EEG spectral power approximately every six months for two years prior to grade school at age 6 years and characterized frontal brain maturation using a growth curve analysis of proportion of spectral power in relative faster (i.e., alpha) -to-slower (i.e., delta) EEG frequencies. We found that children classified as low in shyness exhibited a significant linear growth in the proportion of overall frontal alpha power relative to delta power across assessments relative to children classified as high in shyness (β = 0.007, p = .04). High shy children displayed no growth in the proportion of overall frontal alpha power relative to delta power across assessments. These preliminary results indicated that high shy children exhibited delayed frontal brain maturation compared to low shy children.
In Study 2, we examined the relations among shyness, frontal brain activity, and anxiety in an ecologically salient context: preoperative setting. Participants were 30 typically developing children (8 to 13 years) undergoing elective surgery. Shyness was measured at T1 (preoperative visit) using maternal report. Regional EEG data were collected continuously using a portable ambulatory EEG headband at T1 and on the day of surgery (Time 2; T2) along with children’s self-reported preoperative anxiety. We found that shyness was associated with (1) increased preoperative anxiety (β = -.47; p = .02), and (2) this relation was fully mediated by children’s overall frontal EEG alpha power (i.e., average of T1 and T2) (p < .05).
Taken together, these disparate preliminary findings raise the possibility that (1) delayed frontal brain maturation might play a role in shyness, and (2) patterns of frontal brain activity may link temperamental shyness and anxiety risk in some stressful contexts. Theoretical and practical implications for understanding relations among temperament, context, and anxiety are discussed.

Authors

• Cheryl Chow, McMaster University
  Presenting Author

• Kristie L. Poole, McMaster University
  Non-Presenting Author

• Louis Schmidt, McMaster University
  Non-Presenting Author