The neurology of tickling: a 10 minute presentation for an audience of fellow neural engineering students.

1. BRAIN TICKLER

2. PALETTE CLEANSER

3. TYPES OF TICKLING
Knismesis Gargalesis
Produced by Light touch Hard rhythmic probing
Localized to Anywhere on body Specific locations (Ribs, stomach)
Can be self-induced? Yes No
Present in Most mammals Primates
Purpose Scratch/rub tickled spot ?????
 Different parts of the brain activated when hearing emotional and ticklish
laughter
(Harris 2012)
(Blakemore 2000)

4. PSYCHOLOGY OF TICKLING
Is tickling a conditioned response to play?
• Leuba refrained from tickling his 2 babies in playful
situations
• Tickled babies while wearing a mask
• Regardless, ticklish laughter emerged at ~6-7 months
• 1940s psychology was a wild time
 Tickled laughter is not a conditioned response
Is laughter from tickling the same as laughter from humor?
• C R Harris found humorous laughter has a ‘warm-up’ effect
• Does tickling ‘warm-up’ a subject to laughter the same way stand-up comedy
does?
• Subjects exhibited similar laughter watching comedy regardless of ‘warm-up’
tickling
 Laughter from humor and tickling don’t share common underlying mechanisms
Is tickling all in our head?
(Leuba 1941)
(Harris 2012)

5. TICKLING ROBOTSDoes tickling require another person?
Can a “robot” tickle us the same way a human can?
• Subjects told they’d be tickled once by a human and once by a machine
• Research assistant hidden under table wearing “robot” arm tickled subjects
• Tickling “robot” from plastic hand, vacuum hose, and nebulizer for sound effects
• Perceived as equally ticklish for human or “robot”
 Ticklish laughter isn’t a social response
Can we tickle ourselves WITH a robot?
• Subjects controlled a robot arm that tickled their opposite hand
• Unpredictable 0-200ms delay added to some of the motions
• No delay perceived as least ticklish
• Ticklishness increased as delay increased
 Ticklishness caused by unpredictability of the stimulus NOT the stimulus itself
(Harris 1999)
(Blakemore 2000)

6. NEUROLOGY OF TICKLINGMore than a reflex
Ticklishness results from interpretation of a stimulus
(Blakemore 2000)
(Kolb 2001)

7. SO WHAT’S THE PURPOSE OF TICKLISHNESS?
Play-face, panting “laughter”
Mother tickling baby
 Encourage protecting vital areas
 Parent-offspring bonding
Evolutionary benefits

8. REFERENCES
Harris, C. R. "Tickling." (2012): 611-615.
Blakemore, S.J., Wolpert, D., et al., 2000. Why can’t you tickle yourself? NeuroReport 11 (11), R11 –R16
Leuba, Clarence. "Tickling and laughter: Two genetic studies." The Pedagogical Seminary and Journal of Genetic
Psychology 58.1 (1941): 201-209.
Harris, Christine R., and Nicholas Christenfeld. "Can a machine tickle?." Psychonomic bulletin & review 6.3 (1999):
504-510.
Kolb, Bryan, Ian Q. Whishaw, and G. Campbell Teskey. An introduction to brain and behavior. New York: Worth,
2001.