Ever find yourself doing something without knowing exactly why? You might swat at a fly before you consciously realize it is there, or you might catch yourself scratching a bug bite you were trying to forget about. A new study published in Psychological Science could help explain why: half of the brain can be subliminally motivated while the other half is left in the dark.
Researchers at INSERM in Paris first measured how hard 33 subjects could squeeze a grip with each hand. Then they presented the subjects with images on a computer screen of either a one-euro coin or a one-cent coin. The coins were visible to only one eye at a time, and they appeared for only 17 milliseconds—long enough for subliminal, but not conscious, processing. After each coin image flashed, the subjects squeezed the grip with whatever hand they were holding it in—they were told they would win a fraction of the coin’s value depending on the amount of effort they exerted. Each subject got to try all four possible combinations of eyes and hands: right eye with right or left hand and left eye with right or left hand.
Although the subjects could not correctly guess which coin they had seen—confirming that they were not conscious of what they saw—they squeezed harder when presented with the larger coin if the hand grip was on the same side of the body as the eye that had seen it. Their squeezes did not change depending on what the opposite eye saw, indicating that only half the brain was being motivated at a time. Motivation, therefore, is sometimes not only subconscious, explains co-author and INSERM cognitive neuroscientist Mathias Pessiglione, but it can also be “subpersonal,” in that “one part of a person can be motivated while the other is not.” So next time you are surprised to find yourself midaction, consider blaming it on the independent halves of your brain.
This article was originally published with the title Split Motivation.
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6 Comments
Add CommentA fraction of a euro as reward... and it worked!
Reply | Report Abuse | Link to thisSigh!
Would be interesting to 'see' if brains of one eyed people learn to compensate for this effect (ie. link the eye with opposite hand/side)
Reply | Report Abuse | Link to thisFlashing an item in one visual hemifield at a time is *not* the same as flashing an item to one eye at a time! Left and right half of each eye's view go to right and left half of the brain, respectively.
Reply | Report Abuse | Link to thisNice to see the science of subliminal perception advancing after so many years of being neurosciences "red headed step child".
Reply | Report Abuse | Link to thisIt would be intesting to see if people who were blind, but who had "blindsight" were also so motivated.
I'll forgive the authors for not going into to too much detail about fields of vision and such. One can't expect too much from science writers and popularizers. As long as the reseachers got it right and the peer review process verifies that they did, I'm content.
The fact that each part of the brain has its own selves is well known and established long back.Actually as Searle points out based on the views of Enlightenment philosophers and the more modern splitbrain experiments of Roger Sperry,there is a central self controlled by the prefrontal cortex with its unimodal cortical associations that implement the neuronal self.As Locke has pointed out a generating mechanism for the ego and the self with its unity of beliefs and attitudes can be found in some of the ancient brain centers in the limbic system which controls memory ,emotions and learning.However in a relentless manner Hume had held that self cannot be known by introspection since we have no direct knowledge of raw sensory inputs and data.We have only perceptions,of the self. Neuroimaging studies in patients and in cases like blindsight reveal that self is an illusion in the brain ,and loss of brain parts or impairment can lead to a malfunctioning of the self.
Reply | Report Abuse | Link to thisRegarding the discriminations that self sense imposes ,these are due to a self boundary in the frontal lobes of the right brain as neuroscientists have proven. hence despite the unity of self consciousness as proven by phenomena like binocular rivalry self is a virtual entity in the hymns or eulogies of ego and self and its consciousness. Mnay brain parts are involved in creating this illusion in brain ,and as Descartes held self is not an emergent property either in brain ,at the pinnacle of hierarchic network processing of neural circuitry.Many parts of the network are simultaneously and sequentially involved. So situations like the right not knowing what the left does is quite common ,though the circuitry in brain is primed for unity of consciousness.
Experiments even reveal that there is unity of contents in wakeful thought and dreamstate cognition. Brain doesnot differentiate between the dream and the waking state,but the unity of self is still being maintained unconsciously ,despite the fact that there are many selves in the brain ,each of which doesnot know what the other does.
SURESHKUMAR.S,SCIENTIST AND ADVISER,NIIST,CSIR,INDIA