mrz
10-07-03, 19:21
Brains hardwired to underestimate own strength
19:00 10 July 03
NewScientist.com news service
Human brains are wired to underestimate the amount of force exerted on other people, a study of "tit-for-tat" experiments has revealed.
As well as qualifying the teary "she hit me harder" playground argument and explaining why we can't tickle ourselves, the discovery may provide insight into some self-delusional symptoms of schizophrenia.
To test the notion that the brain downplays sensations generated by body movements because it can predict what will happen, Daniel Wolpert and colleagues at University College London in the UK engaged six pairs of adult volunteers in "tit-for-tat" experiments.
Each volunteer took turns to squash their partner's left index finger below a lever recording the amount of force applied. Their partner was instructed to reply to each push with equal force. The researchers quickly discovered that both volunteers pushed harder and harder on the lever. Afterwards the volunteers were surprised to learn that everyone had been given the same instructions and that their partners had not been asked to increase the force used.
Equal force
In a second experiment, subjects were asked to apply pressure to one of their own fingers with force equal to that generating by a mechanical device. Repeatedly they over- judged the force required, leading the team to conclude that the brain perceives self-exerted forces as weaker than they actually are.
"From the brain's point of view events in the outside world and those generated by yourself get mixed together," Wolpert told New Scientist. "The brain separates them using prediction."
When the body makes a movement a message is sent to the brain warning it what to expect. In this way, the brain predicts and already knows the outcome of an action before it is performed. This explains why you cannot tickle yourself - your brain already knows what to expect and de-sensitises the signal from your skin.
Wolpert says this may help to explain schizophrenic symptoms involving delusion of control. "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," he explains.
Journal Reference: Science (vol 301, p187)
Hazel Morris
http://www.newscientist.com/news/news.jsp?id=ns99993929
LOL!!! Aliens... omg. Het stuk spreekt zichzelf wat dat betreft beetje tegen als je mij vraag hoor...
Human brains are wired to underestimate the amount of force exerted on other people
en dan...
They might claim the movements are generated by other beings, such as aliens, although they are made by themselves
Wat is het nou?
"Some schizophrenic people generate a movement but can't predict what is going to happen.
Ja maarja... Sommige mensen kunnen voorspellen wat gaat gebeuren en da's ook geen lol aan... :P
19:00 10 July 03
NewScientist.com news service
Human brains are wired to underestimate the amount of force exerted on other people, a study of "tit-for-tat" experiments has revealed.
As well as qualifying the teary "she hit me harder" playground argument and explaining why we can't tickle ourselves, the discovery may provide insight into some self-delusional symptoms of schizophrenia.
To test the notion that the brain downplays sensations generated by body movements because it can predict what will happen, Daniel Wolpert and colleagues at University College London in the UK engaged six pairs of adult volunteers in "tit-for-tat" experiments.
Each volunteer took turns to squash their partner's left index finger below a lever recording the amount of force applied. Their partner was instructed to reply to each push with equal force. The researchers quickly discovered that both volunteers pushed harder and harder on the lever. Afterwards the volunteers were surprised to learn that everyone had been given the same instructions and that their partners had not been asked to increase the force used.
Equal force
In a second experiment, subjects were asked to apply pressure to one of their own fingers with force equal to that generating by a mechanical device. Repeatedly they over- judged the force required, leading the team to conclude that the brain perceives self-exerted forces as weaker than they actually are.
"From the brain's point of view events in the outside world and those generated by yourself get mixed together," Wolpert told New Scientist. "The brain separates them using prediction."
When the body makes a movement a message is sent to the brain warning it what to expect. In this way, the brain predicts and already knows the outcome of an action before it is performed. This explains why you cannot tickle yourself - your brain already knows what to expect and de-sensitises the signal from your skin.
Wolpert says this may help to explain schizophrenic symptoms involving delusion of control. "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," he explains.
Journal Reference: Science (vol 301, p187)
Hazel Morris
http://www.newscientist.com/news/news.jsp?id=ns99993929
LOL!!! Aliens... omg. Het stuk spreekt zichzelf wat dat betreft beetje tegen als je mij vraag hoor...
Human brains are wired to underestimate the amount of force exerted on other people
en dan...
They might claim the movements are generated by other beings, such as aliens, although they are made by themselves
Wat is het nou?
"Some schizophrenic people generate a movement but can't predict what is going to happen.
Ja maarja... Sommige mensen kunnen voorspellen wat gaat gebeuren en da's ook geen lol aan... :P