LAST month, two kindergarten classes at the Blue School were hard at work doing what many kindergartners do: drawing. One group pursued a variation on the self-portrait. “That’s me thinking about my brain,” one 5-year-old-girl said of her picture. Down the hall, children with oil pastels in hand were illustrating their emotions, mapping where they started and where they ended. For one girl, sadness ended at home with a yummy drink and her teddy bear.