There is an interesting story in the Indian epic Ramayana about Shravan Kumar who carried his aged and blind parents in two baskets hanging on his shoulders, taking them to various holy places for pilgrimage.  This story is always told by parents and elders to young children as an example of how a son should be devoted to his aged parents and take care of them.
 
The story also says that when Shravan Kumar reached somewhere near the vicinity of Meerut or Hastinapur, suddenly negative thoughts came to his mind regarding his parents; for example why he was wasting his life ferrying his aged parents; he should abandon them since they are aged anyway, etc. etc.  Only when he left the area then these thoughts vanished.
 
Changes in earth’s gravitational and magnetic (gravimagnetic) field affect the mind.  Brain produces low level electromagnetic (EM) field as a part of its thinking process. Our present age is an electric age and thus we cannot help being engulfed in EM fields. Whether they are from our cell phones, or overhead high voltage wires, or microwave ovens, or MRI scans, etc., we are continuously bombarded by them and cannot escape them. These man-made fields together with the fluctuations in earth’s magnetic fields created by solar storms provide a very large number of possibilities of affecting the human thought process. The exact mechanism of how this happens is not presently understood.
 
Nevertheless scientists have used magnetic fields (both static and dynamic) for treating brain disorders.  Thus depression, some forms of fits and headaches have been treated by applying small amount of static and dynamic magnetic fields on human skull. Some have even suggested that such cranial treatments gives them better sleep and reduction in anxiety.  
 
It has also been discovered that the functioning of the brain of astronauts who stay for long time in microgravity environment of outer space is adversely affected. Tests done on them after they return to earth show reduction in their response time and sharpness of mind. How the microgravity affects the functioning of the brain is still not understood.
 
Nevertheless there is enough data to show that changes in geomagnetism and gravitational fields affects the brain and hence thought.
 
Some speculation on how gravity affects thought can be seen in the interaction of alpha waves with earth. Alpha waves are produced in the brain when we are in meditation or relaxing mode. These waves are generally in the range of 8-12 Hz frequency. The earth’s diameter (~ 12,800 km) is such that it can have a standing half-wave of 11.7 Hz (very close to 12 Hz).  Is it therefore possible that our brain evolved in such a manner that the earth’s geometry (and hence its gravity) influenced the alpha wave production? Incidentally scientists have also discovered that before major earthquakes an electromagnetic wave of 0.01-10 Hz comes from deep inside the earth. This wave is sometimes sensed by animals and could be the basis of reported earthquake prediction by them. In some other habitable planet the living beings may have different alpha waves depending on the geometric shape and size of that planet.  Similarly life on other planets may evolve according to their gravity fields besides the effect of other environmental variables.        
 
The relationship between alpha waves and earth’s gravity may have other implications. Practitioners of Bhakti Yoga (devotional yoga) and Buddhist traditions have always stressed the need to allow full flow of thought waves without any interference from ego or sense of identity ‘I’ for achieving Samadhi. Bhakti Yoga and Buddhist tradition says that one should completely sublimate the ego ‘I’ by abandoning oneself to God or Universal Consciousness.  I feel both these practitioners are intuitively trying to allow the mind to get tuned to the gravitational field of the earth resulting in meditation and 'samadhi'. 
 
Also both gravitational and magnetic fields of the earth, world over, vary slightly from their mean values. Since they can affect the working of the brain, it is possible that some places may be more conducive to creating deep thought and creativity. In ancient times this could have been one of the bases of site selection - for setting up temples and religious shrines around the world.
 
There is a strong scientific evidence that the earth’s magnetic poles will flip over. That is the magnetic North will become South and vice versa. When that will happen is anybody’s guess but it is long overdue. Flipping of poles will allow increased bombardment of earth by solar wind and cosmic radiation since the protective shield provided by earth’s magnetic field will weaken. This may affect the communication and weather. But more than that I feel it may affect human thought in a substantial manner. In what way is open to question!        
 
(The author is a US-educated engineer who is now  Director, Nimbkar Agricultural Research Institute (NARI), Phaltan, Maharashtra.  He can be contacted at anilrajvanshi@gmail.com )