This week’s Psychology in the News focuses on the odd behaviour of tickling and being ticklish. Scientific American reports on the latest research into this behaviour.

Tickling is a sensation that neuroscientists are increasingly trying to understand how the brain processes touch, emotion and social interaction. In modern laboratories, researchers use highly controlled methods, including a tickle robot called Hektor, which uses electric motors to stroke participants’ feet with probes while their responses are measured. Participants rate how ticklish each touch feels on a scale of 1 to 10 while researchers record facial expressions, heart rate, breathing, muscle activity, skin conductance (to measure sweating) and brain activity using electrodes attached to the scalp.

Although tickling is recognised by most humans, researchers still do not fully understand why it exists. Evidence suggests that tickling may be evolutionarily significant because it is seen in humans and primates such as chimpanzees, gorillas and orangutans. Studies involving rats have shown that stroking areas of the body produces increased vocalisations and activates areas of the brain associated with pleasurable sensations.

Researchers also argue that tickling appears to transcend culture. In one study, participants from more than 20 different cultural backgrounds, including individuals from the UK, Poland, India and Hong Kong, listened to recordings of German speakers laughing. Despite the language differences, participants were consistently able to identify which laughter had been caused by tickling rather than by happiness or schadenfreude (a German word which means to derive pleasure from another’s misfortune, e.g. laughing at someone who has fallen over). This suggests that tickling and the sounds associated with it may be universally recognised human behaviours.

Several explanations have been proposed for why tickling evolved. Some researchers believe it may simply be a reflex with no specific function, while others suggest it helps strengthen social bonds, especially between parents and children. Another theory proposes that tickling acted as a form of mock fighting, helping young humans learn defensive skills and identify vulnerable areas of the body.

Research has also shown that neurodivergent individuals may process tickling differently. For example, one study suggested a less favourable emotional response towards being tickled in children with autism. Furthermore, another piece of research suggested that people with schizophrenia were less able to predict and process the sensation of touching themselves, meaning that self-touch was perceived as more intense and more likely to feel ticklish than it does for people who process touch in a more typical way.

References:

The surprising science of tickling: Scientists built a tickle robot to solve one of biology’s strangest mysteries | Scientific American (accessed 14.5.26)

ANSWER THE FOLLOWING QUESTIONS!

1. According to neuroscience research, tickling appears to be a universal behaviour. What is meant by ‘universality’?
2. Using a tickle robot could be said to be much more scientific than asking a human to tickle another human. Explain why with reference to at least one feature of science.
3. Neuroscience research often involves ‘placing electrodes on participants’ scalps. Which method of studying the brain is this likely to be, and why?
4. Tickling is believed to be an ancient evolutionary behaviour. Use your knowledge of evolution to explain why the behaviour of tickling still exists in humans today.
5. In the article, the authors suggest that tickling could be a behaviour which exists to help build the bond between infant and carer. Which theory of attachment which you have learned about does this relate most closely to?