serious concentration

I've always wondered why some people stick out their tongues when they are in deep concentration. This is something I've always done when I'm using scissors or lifting something heavy. I've noticed Emma Jane doing this recently. Is this a trait you're born with or a learned behavior? No matter how she picked up this habit, it's cracking me up! To preface the last photo let me say that YES, she is wearing her bike helmet while helping me replenish Walker's bones. No, it's not a dangerous activity. She just loves that goofy yellow bike helmet and wears it around the house all the time. Why? In Emma Jane's words, "So I can be safe!"