Zenith Grant Awardee

Joseph Kirschvink

California Institute of Technology

Co-Investigators

Shinsuke Shimojo, California Institute of Technology; Felicity Meakins, University of Queensland

Project Title

Cross-Linguistic EEG Comparisons on the use of Geomagnetic Cues by the Human Brain as a Path for Understanding Consciousness

Project Summary

Consciousness depends in part on our ability to detect environmental stimuli (sight, hearing, touch, taste, smell, etc.). Our recent discovery that humans possess a functioning geomagnetic sensory system like that used by migrating and homing animals extends the list of human senses; however, none of our subjects claimed conscious awareness of the geomagnetic field. So far, all the human subjects we have tested are native speakers of languages that use egocentric orientation terms (e.g., ‘left’, ‘right’). Individuals raised from an early age speaking and using languages that use geocentric orientation terms (e.g. ‘North’, ‘South’, ‘East’, ‘West’) such as the Gurindji People of northern Australia may have made associative links with geomagnetic sensory cues to aid in daily life. They may be consciously aware of the geomagnetic field, but do not attribute their awareness to a magnetic sense. We propose to do EEG based magnetoreception experiments, similar to those we have run on human subjects in the Northern Hemisphere, on native speakers of these languages. If magnetoreception is part of their conscious awareness, it could open a new window into the neurological activity that defines consciousness itself.

Technical Abstract

Earth's biosphere gained the ability to use the geomagnetic field with the Archean evolution of the magnetotactic bacteria, which precipitate intracellular compass needles of the ferrimagnetic mineral magnetite (Fe3O4). This mineral is also the biophysical mechanism in magnetotactic protists, invertebrates, fish, amphibians, reptiles, birds and mammals, helping them to orient and navigate with the geomagnetic field. We reported last year the discovery that humans also have a geomagnetic sensory system; small rotations in the magnetic field direction trigger up to 50% drops in the brain's EEG alpha-wave power. None of our experimental participants report having been consciously aware of the magnetic field shifts. However, all of our subjects speak Indo-European languages that use egocentric terms (e.g. 'left', 'right'). In contrast, speakers of many other human languages rely on geocentric reference cues (e.g. 'North', 'South', 'East', 'West') to express location and lack egocentric terms. Their ability to casually and accurately keep track of their spatial orientation suggests that they might be consciously aware of the geomagnetic field, but do not know it as such. We propose to test this experimentally; comparison of the magnetic influence on brainwave patterns could give us clues to the neurophysiological nature of consciousness.