Mark Greener describes how research is pointing to humans’ own magnetic compass
Every time I get close to certain Avebury stones, an area I know and love, I experience a definite, palpable sensation lurking on the edges of my perception. Sadly, I wasn’t thrown back like Roj Blake (OK, it was Adam Brake in Children of the Stones, but Gareth Thomas will always be Blake to me). And it’s not solely familiarity and affection; a similar sensation arose when I visited the Hurlers for the first time in the summer of 2015. Sceptics would, of course, ascribe the feeling to the atmosphere intrinsic to mythical landscapes working on my preconceptions.
But a few days after visiting the Hurlers, I was sitting fiddling with the crystal pendulum that now adorns our kitchen window while my wife and kids collected various crystals at a shop in Glastonbury. Idly, I made the pendulum move widdershins, stop and then rotate in the opposite direction (Conscious micromuscular movements, of course). Then, over one area of the flagstone floor, I felt a distinct ‘tug’. I thought the pendulum had slipped. But it hadn’t – and the pendulum did the same thing at the same place again and again. Sceptics would, of course, ascribe the pendulum’s movement to my imagination manifesting as subconscious micromuscular movements.
However, since reading Colin Wilson’s Beyond the Occult far back in the mists of ancient time – the late 1980s – I’ve assumed such sensations are manifestations of our innate ability to sense variations in geological magnetic fields. Wilson noted that zoologist Robin Baker – whose pioneering research we’ll look at – “proved conclusively” that we “possess an inner compass”.
Indeed, the idea that humans might have an inner magnetic compass isn’t that surprising: microbes, migrating birds, sea turtles, wood mice, mole rats, wild boars and warthogs all seem to sense the Earth’s magnetic field.1-4 Research published earlier this year found that boars and warthogs seem to prefer a N-S alignment when foraging or resting, for example.3 Cattle and deer also orientate their bodies while grazing.4 Dogs, apparently, point N or S while defecating and urinating.4 But the idea that humans might sense the magnetic field remains deeply contentious.4,5 Now, Science reports, high-tech research seems to confirm the existence of a magnetic sixth sense in humans.4
On the buses…
In the late 1970s, Baker studied groups of 5-11 university students who had lived in Manchester for at least two years. They were driven 6-52 km from the university, blindfolded, in silence and by a “tortuous route”. At the end of the journey and while still blindfolded, the 64 students were asked to indicate the university’s direction. Some students took part in more than one experiment. So Baker analysed 86 estimates. In another experiment, 42 sixth-form students were blindfolded and ‘released’ 22 km away, again after taking an indirect route of 40km. In this case, a TV company chose the subjects.6
Baker’s research offers compelling evidence that “humans have an ability to recognise homeward direction even in the absence of visual cues”.6 The students were “moderately accurate”. For instance, their average error was just 47o compared to the 90o expected from chance. Other measures confirmed that humans have an inner compass that allows them to recognise directions. Indeed, the likelihood that the various measures of directional accuracy occurred by chance was less than 1 in 100.7 To put this in context, biologists – in studies of new medicines, for example – usually accept a finding with a 1-in-20 likelihood of occurring by chance as being a ‘real result’ (The technical term is statistical significance).
Directional accuracy did not seem to differ with distance, familiarity with the area once the blindfold was removed, or solar cues: people could recognise the direction even on totally overcast days. The route was convoluted, which makes it extremely unlikely that the students drew a mental map.6 However, a bar magnet held in the blindfolds seemed to disrupt the ability to correctly indicate the direction. A brass bar of the same size and weight had no effect. All these students believed that they were wearing the magnet.6
Baker’s findings seem to offer evidence for ‘route-based’ non-visual magnetic navigation in humans “qualitatively similar” to results “obtained on homing pigeons transported in altered magnetic fields”.8 However, an American group failed to confirm the findings in a series of eight experiments. Baker participated in three of these experiments.7 Then researchers from Sheffield analysed 450 estimates of homeward direction made by 133 undergraduates transported to 12 sites. They excluded the possibility that the students were pointing to their parental homes and that a small proportion of ‘poor navigators’ may be responsible for the failure to demonstrate magnetic navigation.8
Nevertheless, in 1987, Baker looked at the evidence from 19 studies assessing human navigation and perception of magnetic fields performed by other researchers. Twelve studies used a ‘winding bus route’. Five studies gently spun blindfolded volunteers on a chair. When the chair stopped, subjects estimated the compass direction they faced.
Two of the 12 bus studies and 2 of the chair studies did not seem to show evidence of non-visual navigation. When Baker combined the data, statistical analysis conservatively suggested that the likelihood that the results occurred by chance was less than 1 in 1000 for non-visual orientation and less than 1 in 200 for perception of magnetic fields.5 Yet Baker noted “the perplexing phenomenon that… positive replications were generating negative interpretations”.5 Since then, other researchers have found tantalising hints of our ability to detect magnetic fields. Unfortunately, the results were not reproducible from day to day.4
A high-tech approach
Then in June 2016, Science reported that Joe Kirschvink, a geophysicist at the California Institute of Technology, seems to have found evidence for our ability to detect magnetic fields using a sophisticated technique. Instead of interpreting behaviour, Kirschvink’s team uses a Faraday cage to exclude electromagnetic noise from, for example, computers and radio. They apply a rotating magnetic field, similar in strength to the Earth’s, to a volunteer and used EEG recordings (‘brain waves’) to measure any response.4
At a recent scientific meeting, Kirschvink presented the results from 24 volunteers, that consistently and reproducibly showed that rotating the magnetic field produced changes in the EEG (It’s worth reading the report, available free online, which includes more details and an accessible account of how the sense might work). Kirschvink’s studies add to the growing body of evidence that humans can detect the Earth’s magnetic field.4
In Beyond the Occult, Wilson noted that the ability to detect changes in the Earth’s magnetic field might help account partly for dowsing, leys, some ghostly apparitions and amplify ’emotional currents’. Despite the scepticism among some scientists, as a biologist I’ve always believed in our inner compass. I couldn’t see why, in evolutionary terms, we would have lost a such an intrinsically useful sense that is widespread throughout the bacterial and animal kingdom (the technical term is ‘highly conserved’). After all, maps are too recent to affect natural selection. Now some 40 years after Baker’s pioneering work, a growing body of evidence suggests we almost certainly have an inner compass. As Baker told Science: there is “not a shadow of doubt in my mind: Humans can detect and use the Earth’s magnetic field”.4
- Emlen, S T, Wiltschko, W, Demong, N J, et al. Magnetic Direction Finding: Evidence for Its Use in Migratory Indigo Buntings. Science. 1976;193:505-8.
- Foley, L E, Gegear, R J, Reppert, S M. Human cryptochrome exhibits light-dependent magnetosensitivity. Nature Communications. 2011;2:356.
- Červený, J, Burda, H, Ježek, M, et al. Magnetic alignment in warthogs Phacochoerus africanus and wild boars Sus scrofa. Mammal Review. 2016:DOI:10.1111/mam.12077.
- Hand, E. Maverick scientist thinks he has discovered a magnetic sixth sense in humans Science on-line http://www.sciencemag.org/news/2016/06/maverick-scientist-thinks-he-has-discovered-magnetic-sixth-sense-humans. 2016.
- Baker, R R. Human navigation and magnetoreception: the Manchester experiments do replicate. Animal Behaviour. 1987;35:691-704.
- Baker, R. Goal orientation by blindfolded humans after long-distance displacement: possible involvement of a magnetic sense. Science. 1980;210:555-7.
- Gould, J, Able, K. Human homing: an elusive phenomenon. Science. 1981;212:1061-3.
- Westby, G W, Partridge, K J. Human homing: still no evidence despite geomagnetic controls. Journal of Experimental Biology. 1986;120:325-31.
Published in NE149 (June 2017), pp.9-11