I have never been a fan of the "left/right brain" dichotomy, and Prof. Kosslyn and Mr. G. Wayne Miller agrees and give us an alternative.
Who hasn't heard that people are either left-brained or right-brained—either analytical and logical or artistic and intuitive, based on the relative "strengths" of the brain's two hemispheres? How often do we hear someone remark about thinking with one side or the other? A flourishing industry of books, videos and self-help programs has been built on this dichotomy. You can purportedly "diagnose" your brain, "motivate" one or both sides, indulge in "essence therapy" to "restore balance" and much more. Everyone from babies to elders supposedly can benefit. The left brain/right brain difference seems to be a natural law.
Except that it isn't. The popular left/right story has no solid basis in science.In most science literature, the left/right story has been criticized for decades, including most serious popular science writing. We can still easily find such story in any airport bookstore, and sometimes even in bestselling list. Those are business books. They are an agenda that needs something with the appearance of science to back it up.
Here is the alternative:
There is a better way to understand the functioning of the brain, based on another, ordinarily overlooked anatomical division—between its top and bottom parts. We call this approach "the theory of cognitive modes." The top brain comprises the entire parietal lobe and the top (and larger) portion of the frontal lobe. The bottom comprises the smaller remainder of the frontal lobe and all of the occipital and temporal lobes. This research reveals that the top-brain system uses information about the surrounding environment (in combination with other sorts of information, such as emotional reactions and the need for food or drink) to figure out which goals to try to achieve. It actively formulates plans, generates expectations about what should happen when a plan is executed and then, as the plan is being carried out, compares what is happening with what was expected, adjusting the plan accordingly. The bottom-brain system organizes signals from the senses, simultaneously comparing what is being perceived with all the information previously stored in memory. It then uses the results of such comparisons to classify and interpret the object or event, allowing us to confer meaning on the world. The top- and bottom-brain systems always work together, just as the hemispheres always do. Our brains are not engaged in some sort of constant cerebral tug of war, with one part seeking dominance over another. (What a poor evolutionary strategy that would have been!) Rather, they can be likened roughly to the parts of a bicycle: the frame, seat, wheels, handlebars, pedals, gears, brakes and chain that work together to provide transportation. But here's the key to our theory: Although the top and bottom parts of the brain are always used during all of our waking lives, people do not rely on them to an equal degree. To extend the bicycle analogy, not everyone rides a bike the same way. Some may meander, others may race. Beyond what is required by a particular situation (your reaction, say, to a car speeding toward you), all of us can use each system in optional ways. You can use the top-brain system to develop simple and straightforward plans, as required by a situation—or you have the option to use it to develop detailed and complex plans (which are not imposed by a situation). Our theory predicts that people fit into one of four groups, based on their typical use of the two brain systems. Depending on the degree to which a person uses the top and bottom systems in optional ways, he or she will operate in one of four cognitive modes: Mover, Perceiver, Stimulator and Adaptor.And take a 20-question quiz to find out.