The Science of Tickling: Why We Laugh and Can't Tickle Ourselves

• Tickling involves two types: Knismesis (discomfort, no laughter) and Gargalesis (vigorous touch, laughter, seen in humans and some monkeys).
• Laughter from tickling is a 'defense mechanism,' not joy; the brain interprets sudden touch on sensitive areas as a threat.
• We can't tickle ourselves because the cerebellum anticipates the touch, canceling the surprise and danger signals.
• Sensitive body parts like armpits and soles are targeted due to high nerve density, a natural defense mechanism from ancient times.
• Historically, 'tickle torture' was used to extract information, as continuous tickling can cause exhaustion and breathlessness.