The Enigma of Tickling: Unraveling a 2,000-Year-Old Mystery

Tickling has fascinated humans for thousands of years, yet despite centuries of curiosity and research, it remains one of the most mysterious sensations in neuroscience. Historically, thinkers like Socrates and Darwin pondered the nature and purpose of tickling, but many questions remain unanswered. Why can’t we tickle ourselves, and why do some people find it unbearable while others enjoy it? According to neuroscientist Konstantina Kilteni from the Donders Institute, understanding the neural mechanisms behind tickling could offer profound insights into brain function.

Kilteni emphasizes that tickling involves a complex interplay of motor, social, developmental, and evolutionary factors. It plays a role in strengthening bonds between parents and children, as it is often used as a playful interaction. Exploring how the brain processes ticklish stimuli can reveal important aspects of brain development, particularly in children, and could shed light on neurological conditions such as autism spectrum disorder (ASD). Research indicates that individuals with ASD perceive touch, including tickling, differently, with some experiencing it as more intense or unpleasant. Studying these differences may enhance our understanding of autism and contribute to improved interventions.

From an evolutionary perspective, tickling is observed not only in humans but also in other primates and even rodents. The purpose of tickling, from this angle, might be linked to social bonding, play, or even survival strategies. Interestingly, humans cannot tickle themselves because the brain predicts and cancels out self-generated sensations, but the exact neural processes behind this are still being investigated.

One challenge in tickling research has been the lack of a clear scientific definition of what constitutes tickling. For instance, the sensation from a gentle feather stroke differs significantly from a more vigorous tickle with hands, complicating experimental replication. To address this, Kilteni has developed a specialized tickling laboratory, where a mechanical device delivers consistent stimuli, allowing scientists to record brain activity and physical responses such as heart rate, laughter, or screams.

By standardizing the method of tickling, researchers aim to deepen their understanding of this intriguing phenomenon and its neural basis. Discoveries from this research could have broader implications for how we understand sensory processing, social interactions, and neurological health.

For more information, see Kilteni's study: 'The extraordinary enigma of ordinary tickle behavior' in Science Advances (2025). Source: https://medicalxpress.com/news/2025-05-enigma-dont-years.html