Blue light-dependent human magnetoreception in geomagnetic food orientation

Abstract

The Earth’s geomagnetic field (GMF) is known to influence magnetoreceptive creatures, from bacteria to mammals as a sensory cue or a physiological modulator, despite it is largely thought that humans cannot sense the GMF. Here, we show that humans sense the GMF to orient their direction toward food in a self-rotatory chair experiment. Starved men, but not women, significantly oriented toward the ambient/modulated magnetic north or east, directions which had been previously food-associated, without any other helpful cues, including sight and sound. The orientation was reproduced under blue light but was abolished under a blindfold or a longer wavelength light (> 500 nm), indicating that blue light is necessary for magnetic orientation. Importantly, inversion of the vertical component of the GMF resulted in orientation toward the magnetic south and blood glucose levels resulting from food appeared to act as a motivator for sensing a magnetic field direction. The results demonstrate that male humans sense GMF in a blue light-dependent manner and suggest that the geomagnetic orientations are mediated by an inclination compass.

Human magnetic sense is mediated by a light and magnetic field resonance-dependent mechanism

“…It is widely accepted that the Earth’s static magnetic field is not sensed by humans, while alternating magnetic fields, such as power frequency fields 26 and pulsed fields 27 , can have adverse health effects and therapeutic applications, respectively. Following previous controversial reports 28 – 30 , two recent studies, using different experimental approaches, support the existence of GMF responses in humans 31 , 32 with a sharp contrast. In a rotary chair experiment, starved men but not women were able to orient in a blue-light-dependent manner towards a particular magnetic direction that had previously been associated with food in the ambient GMF 31 .…”

Perception of static magnetic field by humans: a review

“…The authors reported that food-deprived males, but not females, significantly preferred the magnetic direction that had previously been food-associated. Without food deprivation, neither gender was able to establish such an association (Chae et al, 2019). Gender bias in magnetic orientation the authors cautiously interpret as result of stronger selection for orientation abilities in prehistoric male humans who were dominantly responsible for gathering or hunting for food.…”

“…In a recent study, participants (20 males aged 19-33 years and 21 females aged 19-23 year) were asked to point by hand towards the magnetic North, which may have been rotated in respect to the geographic North by magnetic coils (Chae et al, 2019). Each participant underwent 20 tests in a rotating chair, the results of which were averaged and the mean used in the second-order analysis.…”

“…A detailed inspection of the key result, according to which hungry men can correctly choose the right magnetic direction (which is presented in Fig. 2D, Chae et al, 2019), shows that the statistical significance of the result is based on a single data point, i.e., on a single participant who was very consistent in choosing the right direction. It should also be kept in mind that the authors present the second-order means, i.e., the mean directions shown by each participant in multiple tests.…”

“…Based on the principle that extraordinary claims must be supported by extraordinary robust evidence, we believe that the results of Chae et al (2019) should be treated as promising and preliminary and need independent verification.…”