While it might be somewhat of a myth that big heads equal big smarts (at least for adults), studies have shown that head growth (as measured by head circumference) in infancy is predictive of later intelligence.
My son Damien started out with a perfectly average head circumference at birth (50th percentile), but within one month his head circumference jumped to the 80th percentile, and gradually crept its way upward throughout his first year, reaching the 99th percentile by his first birthday.
Now, at 18 months, his head measured in at a whopping 20.5 inches, and the "99.9th percentile", and is officially "off the charts" (literally).
I guess it's nice to know that the enrichment things we have been doing have been paying off!
"In the morning it flourisheth, and groweth up..." Psalm 90:6Damien is 18 months old