Why Can't we Tickle Ourselves?

kgins's picture

Tickling was always an interesting concept to me.  When we’re tickled, we laugh.  Laughing generally is a sign of joy, or happiness, but when forced, for example, when being tickled, it isn’t as pleasant, or pleasant at all.  I didn’t like that I didn’t have control over what was going on when I was being tickled- that I couldn’t catch my breath from laughing as easily as I could if I was in control.  Later on, someone suggested to me that it was impossible to tickle ourselves to the same effect as if someone else was tickling us.  I wondered if the reason for this was due to a correlation between this feeling of lack of control and the stronger reaction of being more ticklish.  While interest in this topic has only recently greatly emerged and ideas are still being developed, researchers have actually found a part of the brain they believe to be responsible for our ticklish reactions- the cerebellum (1)

 Researchers at the University College London, led by Daniel Wolpert, are suggesting that the cerebellum may hold the answer for why we can’t tickle ourselves- they believe it detects self-inflicted touch before it actually happens, and tells the rest of the brain that it’s going to happen, which sends a signal to desensitize the skin (2).  The UCL team used magnetic-resonance imaging to scan the brains of 16 volunteers who were tickled first by a machine, and then by themselves.  The robotic tickles caused a greater reaction, shown by less action pre-tickle in the cerebellum area, thought to be because the brain didn’t know that the tickles were coming.  The researchers then asked the volunteers to tickle their right hands by activating the robot with their left hands.  When the researchers delayed the movement of the machine by a few hundredths of a second, they still found that the volunteers couldn’t tickle themselves.  However, when they delayed the movement of the machine by longer than one fifth of a second, the self-tickling worked (1). 

This experiment is interesting in suggesting that our brains have control over our bodies, know what we’re about to do, and can adjust as to not react greatly to it.  However, I’d be interested in seeing if people with diseases who can’t, deliberately, control their bodies and movements, could tickle themselves if someone else moved their hands onto their bodies.  If they could tickle themselves, that would suggest an interesting connection between human consciousness-or, the ability to be deliberate, cerebellum reception, and signals sent out, rather than, as the researchers suggested, just the latter two steps.  I think the number of test subjects, 16, also isn’t great enough to make any solid suggestion or conclusion, and many more test subjects would be needed to establish something more here.

As far as the brain knowing beforehand and preparing the body for the reaction, or, for the non-reaction- it bothers me a little.  According to this study- and experience, we’re more likely to be more ticklish when someone- or something- else, rather than ourselves, tickles us.  While this could be a kind of protection mechanism- saving the stronger response for a greater potential, outside threat- it seems like there’s a lot of room for error.  It’s amazing if our brains can accurately detect something we do to ourselves versus something from the outside, but it seems there must be some place where the brain could mess up- some potential room for error.  I’m hesitant to trust that our brains are error-proof, and always know what touch is coming from where.  Even though our brains do have great control over the rest of our bodies, I’d want to research the errors the brain can make here- it seems some neurological disorders could potentially destroy this mechanism, and so I wonder, what other mechanisms do we have to detect outside stimuli from the ones we produce ourselves?

This research also may play a role in better understanding schizophrenia.  Wolpert says his research may help explain schizophrenic symptoms involving delusion of control (3).  He says, “Some schizophrenic people generate a movement but can’t predict what is going to happen.  They might claim the movements are generated by other beings, such as aliens, although they are made by themselves” (3).  Here, with schizophrenia, there’s a relative control over bodily movements, but not with timing or definite awareness.  Wolpert also says that he is not certain whether or not people with schizophrenia can tickle themselves, but says that since their falsely alien sensations are often associated with fear and paranoia, it is likely that the experience would not be pleasurable (4). 

Earlier in this paper, I wondered whether people with a lack of physical control over their bodies could self-tickle themselves, since, in a way, it’d be a surprise (but they wouldn’t actually be able to tickle themselves most likely since they don’t have this control).  Schizophrenia is interesting in a different way, but along similar lines.  Schizophrenics think things are happening outside of their bodies that appear to come from within them.  If this tickling experiment and research goes further, gaining more exposure, and more results, we really may be able to see into schizophrenia on a level we haven’t seen into before.  At the same time, I wonder how much we, as non-schizophrenics, can understand about what we call a disorder, when, we don’t know if those voices are actually there or not.  We call this a “disorder”, because we don’t hear the voices, because we don’t understand- so, maybe with time, we’ll find that schizophrenics can have some kind of receptors we don’t have, something that maybe, in some way, benefits them.  Or, we may find a connection in the brain that we hadn’t seen before- either way, tickling research could greatly benefit the understanding of schizophrenia.

Wolpert’s research right now is the leading research in the area of tickling.  The interest in tickling, and the body’s reaction, is quite recent, and has much room for questioning and experimenting.  With finding possible connections between the body’s response to being tickled, and delusions related to bodily movement with schizophrenia, research should be taking off soon.  There is little controversy right now in the area of tickling, because research has only just started, with only the very beginning of the basics being suggested.  Even then, basics get questioned, but as of the moment, Wolpert’s research is still only just being taken in.

If the reason we can’t tickle ourselves is because we’re too aware and able to not be alarmed by the sensation, then I’d be interested in researching and finding out more about what tickling actually is, rather than the stimuli and reactions.  After we’re tickled, what happens in that immediate reaction?  Why is it that moving our fingers in a certain way on certain body parts of someone else creates such a strong effect- some part of it seems it must be sexual, but then, is there a correlation between a more sexual person and a more ticklish person? Maybe it a fear that someone else is touching us- that we’re uncomfortable, and we laugh as a way to calm ourselves.  The research being done on tickling in relation to schizophrenia is interesting, and may provide some new insight into the world of this and other complex disorders. A laughing matter?  I think not. 

 

 

 

Sources:

 

 

1.  How Stuff Works – Why can’t you tickle yourself? http://health.howstuffworks.com/question511.htm

2. Mystery solved: why can’t we tickle ourselves? http://www.cbc.ca/health/story/2000/09/11/tickle000911.html

3. Brains hardwired to underestimate own strength www.newscientist.com/article.ns?id=dn3929

4. News in Science- Why can’t we tickle ourselves? http://www.abc.net.au/science/news/stories/2006/1585716.htm

Comments

inci's picture

answer to ticking

yeah its my reseach subject
im from Turkey
i understand that its the cerebullum which makes me smile, laugh
and it happens when i dont aware of being attacked but the main question is;
when someone says me that he was going to tickle me, im aware of that but no matter what im tickled.. and my brain doesnt stop it.
why?
thanks

GS's picture

Tickling

Karen,

This was a very interesting blog entry. I think your comment about the role of self-control in tickling is on the mark and it's connected to what you write about in your last paragraph. People have suggested that the laughter in tickling is caused by feeling attacked or threatened on one level, but at the same time the person getting tickled knows that the attack is not real. If a person feels truly alarmed in the situation there will be not a ticklish reaction. But if the person doesn't feel at least a little threatened (a little out of control), then there won't be any laughter either. I wouldn't say we laugh in tickling "to calm ourselves down," but, like in many jokes, we laugh because we are caught between two ideas or feelings that are in tension and laughing is a release. Some people have also proposed that the laughter signals to the tickler that the "victim" is OK and the tickling can continue. This kind of play may promote social bonding between people who care about one another.

Jeremy Singleton's picture

follow up to tickling article

I am an undergrad at the University of Florida who studied tickling for a psychology class ... I would be interested to know if you equate the laughter caused by tickling to be related to mirth or if instead you would call it a purely physiological reaction?

Serendip Visitor's picture

Definitely not mirth

I laugh when I am tickled, but not because of joy! I hate being tickled; my dad wouldn't stop and I couldn't catch my breath to ask it so it was tortuous. My son loves to be tickled and begs for it, but I always pause every little bit so he has the opportunity to say he wants more or is done.

I will eventually start crying if I am tickled and I believe part of the laughing response is an outlet or expression for the stimulation, or over-stimulation, of the nerves.

Having said all this, I was challenged to overcome it using mind-over-matter. So, I am going to do this, because I love a challenge!

I do have a question, how much of the tickling is a neurological response? Everyone's tactile sensory system is different. I know mine is likely a little over-sensitive because of a few things that would indicate it is (i.e., can't stand the feeling of walking on grass barefoot).

Regardless, that just makes this mind-over-matter thing all the more of an accomplishment :)!

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