Section: National Report, pg. F04
I think we can all agree on one thing: It's really hard to tickle yourself. You can close your eyes and do it, you can try to think of something else while you do it, it doesn't matter. There have been some pretty cool experiments in the last few years that have at least partly explained this, and now there's a new one.
This new study draws the most amazing connections between schizophrenia, dreaming and tickling. First, some background.
Experiments have shown that the reason we don't laugh hysterically when we tickle ourselves is likely that there's no surprise. The part of your brain that is controlling the tickle sends the message "a tickle's coming" to the part that would normally react to that tickle. There's no surprise and no sensation.
Even brain images have revealed that the key parts of the brain don't bother to react when a person tickles himself. But it's the elaborations on this theme that are the most intriguing. For instance, what if it's not clear whether it's you or someone else who's tickling you? How could that possibly happen? It can if you set up the right experiment.
A group in England built a "tickling machine," a rod with a strip of sponge on the end that could be brushed across a volunteer's hand. If the rod was moved up and down by the experimenter, it was ticklish. If the participant moved the rod him/herself (with the other hand), it wasn't.
In one experiment with this tickling machine, things were made indirect.
The subject moved a robot arm, which in turn moved the tickling arm. If the researchers introduced a slight delay between the time the subject moved the robot arm and the resulting movement of the tickling arm, the sensation was suddenly very ticklish. Apparently, because we're used to our actions leading immediately to results, the delay made it seem as if the tickling had been administered by someone else.
The newest study of self-tickling was inspired by the fact that some of the only people who actually can tickle themselves are schizophrenics.
If you think of that as the tendency to mistake your own actions for the actions of others, it makes sense. Schizophrenics hear voices. These voices are actually their own (sometimes whispered loud enough to be picked up by a microphone) but they don't realize it. They think the voices belong to others, just as they think their own tickling belongs to someone else.
But there is another situation in which we hallucinate and create voices for others: dreams. If dreams are like schizophrenia, at least in this sense, then perhaps people just waking up out of dreams would be able to tickle themselves. I know it's a bizarre concept, but all the more reason to test it.
And so, a British team did. It found that the women in the study did indeed find a self-administered tickle was much more ticklish just after they had been awakened out of a dream. However, the team wasn't able to establish the same thing for men. In fact, many of the men reported self-tickling to be more ticklish than when the lever was moved by an experimenter.
Here is where even tickling experiments get complicated. The experimenter who was moving the tickling arm was a man. When he tickled other men, they reported very little ticklishness.
The experimenters wondered if something social was happening here.
As they put it, "females are more comfortable than are males with same-sex intimacy." Tickling does have a kind of intimacy about it - you can't be tickled if your guard is up. That might have been happening here with the guys.
There's a hint here that many more experiments will have to be done, examining all combinations of gender of participant and experimenter.
So, before all those experiments are reported, time to sum up: We cannot tickle ourselves because the usually reactive part of the brain has been warned not to bother.
However, if there's any uncertainty about who's doing the tickling, all bets are off. That can happen if there's a delay between a person moving a lever and the subsequent delivery of the tickle, but also in schizophrenia, in which people can't discriminate between "self" and "other."
And finally, if these most recent experiments hold up, the hallucinatory world of dreams seems to bring on a similar inability that lingers into wakefulness.
Did I hear you say you thought tickling was simple?
Jay Ingram hosts Daily Planet on the Discovery Channel.
Copyright (c) 2006 Toronto Star, All Rights Reserved.
I think we can all agree on one thing: It's really hard to tickle yourself. You can close your eyes and do it, you can try to think of something else while you do it, it doesn't matter. There have been some pretty cool experiments in the last few years that have at least partly explained this, and now there's a new one.
This new study draws the most amazing connections between schizophrenia, dreaming and tickling. First, some background.
Experiments have shown that the reason we don't laugh hysterically when we tickle ourselves is likely that there's no surprise. The part of your brain that is controlling the tickle sends the message "a tickle's coming" to the part that would normally react to that tickle. There's no surprise and no sensation.
Even brain images have revealed that the key parts of the brain don't bother to react when a person tickles himself. But it's the elaborations on this theme that are the most intriguing. For instance, what if it's not clear whether it's you or someone else who's tickling you? How could that possibly happen? It can if you set up the right experiment.
A group in England built a "tickling machine," a rod with a strip of sponge on the end that could be brushed across a volunteer's hand. If the rod was moved up and down by the experimenter, it was ticklish. If the participant moved the rod him/herself (with the other hand), it wasn't.
In one experiment with this tickling machine, things were made indirect.
The subject moved a robot arm, which in turn moved the tickling arm. If the researchers introduced a slight delay between the time the subject moved the robot arm and the resulting movement of the tickling arm, the sensation was suddenly very ticklish. Apparently, because we're used to our actions leading immediately to results, the delay made it seem as if the tickling had been administered by someone else.
The newest study of self-tickling was inspired by the fact that some of the only people who actually can tickle themselves are schizophrenics.
If you think of that as the tendency to mistake your own actions for the actions of others, it makes sense. Schizophrenics hear voices. These voices are actually their own (sometimes whispered loud enough to be picked up by a microphone) but they don't realize it. They think the voices belong to others, just as they think their own tickling belongs to someone else.
But there is another situation in which we hallucinate and create voices for others: dreams. If dreams are like schizophrenia, at least in this sense, then perhaps people just waking up out of dreams would be able to tickle themselves. I know it's a bizarre concept, but all the more reason to test it.
And so, a British team did. It found that the women in the study did indeed find a self-administered tickle was much more ticklish just after they had been awakened out of a dream. However, the team wasn't able to establish the same thing for men. In fact, many of the men reported self-tickling to be more ticklish than when the lever was moved by an experimenter.
Here is where even tickling experiments get complicated. The experimenter who was moving the tickling arm was a man. When he tickled other men, they reported very little ticklishness.
The experimenters wondered if something social was happening here.
As they put it, "females are more comfortable than are males with same-sex intimacy." Tickling does have a kind of intimacy about it - you can't be tickled if your guard is up. That might have been happening here with the guys.
There's a hint here that many more experiments will have to be done, examining all combinations of gender of participant and experimenter.
So, before all those experiments are reported, time to sum up: We cannot tickle ourselves because the usually reactive part of the brain has been warned not to bother.
However, if there's any uncertainty about who's doing the tickling, all bets are off. That can happen if there's a delay between a person moving a lever and the subsequent delivery of the tickle, but also in schizophrenia, in which people can't discriminate between "self" and "other."
And finally, if these most recent experiments hold up, the hallucinatory world of dreams seems to bring on a similar inability that lingers into wakefulness.
Did I hear you say you thought tickling was simple?
Jay Ingram hosts Daily Planet on the Discovery Channel.
Copyright (c) 2006 Toronto Star, All Rights Reserved.
