Can you tickle YOURSELF?
But, scientists have found some people possess the unnerving ability to tickle themselves.
Furthermore that ability, they say, could be an indication a person is at greater risk of schizophrenia.
For most people, tickling themselves is almost impossible.
The brain recognizes the act as a voluntary one, and as a result it fails to elicit the same sensations as when a person is tickled by a loved one.
However, a team of scientists have found that schizophrenia impairs the predictive process that informs the brain that an act is voluntary.
The researchers, from the University of Lille in France, wrote: 'Successful self-tickling [is] associated with more frequent self-reports of unusual perceptual experiences (such as supernatural experiences) and passivity experiences in particular (such as a feeling of being under the control of an outside force or power).'
Being tickled by another person generally elicits a stronger sensory response than being tickled by yourself, scientists have revealed. Yet, those with schizophrenic-like traits are able to successfully tickle themselves, because their brain cannot recognize that it is a voluntary act
Past studies have confirmed that attempting to tickle oneself has less of an effect than being tickled by someone else.
For instance, a single stimulus - a feather for example - is felt less intensely when self-applied, compared to when it is applied by a friend or family member.
When a person performs a voluntary act, their brain creates 'efference copies' of outgoing motor commands.
Those copies reduce the brain's cognitive load by decreasing the ability to process predictable - and thereby irrelevant - sensory stimuli.
But, when the predictive process is impaired, it can lead to a lower recognition of voluntary actions and incorrectly attribute the self-generated event to an external cause.
That is exactly what happens in people with schizophrenia, the scientists wrote in the journal Consciousness and Cognition.
The scientists conducted a study of 397 participants, each of whom answered seven questions from the Schizotypy Personality Questionnaire.
Eighty participants with extreme scores - 40 with high and 40 with low scores - were then asked to complete the full questionnaire.
The team of scientists selected 27 individuals - 17 women and 10 men, with an average age of 23 - who scored in the upper quartile to participate in the main study.
Those people constituted a group with high schizophrenia-type traits - which are associated with unusual perceptual experiences, bizarre behaviour, odd beliefs and the inability to derive pleasure from social experiences.
The team also selected 27 individuals - 16 women and 11 men - who were considered to have low scores in the schizophrenia-like traits scale.
Scientists conducted experiments using a device (pictured) with a paintbrush mounted on rails - having the participants move the paintbrush themselves at one point, and having someone else move the paintbrush at another. Those with schizophrenic traits found moving the paintbrush themselves to be just as ticklish as having someone else do it, scientists say
Each of the participants wore a mask over their eyes - and then placed their forearm flat on a table, under a device designed for tickling.
The drive had a paintbrush at the end of it - to help with the tickling process.
Participants were first asked to self-tickle, in which they used their dominant hand to make back and forth movements of the paintbrush on their arm.
Next, one of the scientists used the device to move the paintbrush to a specific sound - making the tickling predictable.
Lastly, the scientist moved the paintbrush around at a rhythm that was unknown - and thereby, unpredictable - to the participants.
The study revealed that those with high schizotypal scores (meaning they were more prone to schizophrenia-like traits) didn't find self-tickling to be any less ticklish than being tickled by a third party.
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|Publication:||Balochistan Times (Baluchistan Province, Pakistan)|
|Date:||Mar 31, 2016|
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