Temperament and craniofacial variation in the first two years

Area of Science:

• Developmental biology
• Behavioral science
• Craniofacial development

Background:

• High fetal glucocorticoid levels can inhibit maxilla development, potentially causing cleft palate.
• Mouse strains show differential susceptibility to glucocorticoid effects and exhibit distinct behavioral traits.
• These mouse strain differences parallel temperamental variations observed in human infants.

Purpose of the Study:

• To investigate the relationship between infant temperament and craniofacial morphology.
• To explore potential links between early behavioral reactivity and facial width development.

Main Methods:

• Infant temperament assessed via behavioral observation at 4 months.
• Facial width (bizygomatic breadth) to head/face height ratio measured at 14 and 21 months.
• Comparison of facial measurements between high-reactive and low-reactive infant groups.

Main Results:

• High-reactive infants had significantly smaller bizygomatic ratios (narrower faces) at 14 and 21 months compared to low-reactive infants.
• Facial width differences were modest but statistically significant.
• These differences were not explained by overall body stature.

Conclusions:

• Early infant temperament, specifically high reactivity, is associated with narrower facial width in later infancy.
• Findings suggest a potential connection between early behavioral predispositions and craniofacial development.
• This research may offer insights into the developmental underpinnings of temperament and facial morphology.