Over the past few weeks Felix has discovered a new secret weapon in his bag of tricks -- a completely adorable and utterly disarming smile. It's hard to resist the urge to tickle him, which brings up the curious scientific question: Is the tickling response (laughing) acquired or instinctive? 
Unfortunately, the possibility of using Felix as a test subject has been thwarted by his parents, who both apparently have discovered their own deep-seated instinctive urges to unmercifully tickle his tummy, face, arms, and legs just to see that huge smile that starts in his eyes and then spreads from ear to ear in a perfect, toothless, felicitous smile. 
