In transcranial magnetic stimulation (“TMS”), a coil of wire is placed near the head. Alternating current flowing through the coil induces a magnetic field with a strength of up to 2.5 teslas (one tesla is 20,000 times the strength of the earth’s magnetic field). The field passes harmlessly through the skull and influences the electrical signals passing among neurons in the brain.
(Image and quote from Progress Daily.)
TMS has been used to stimulate or suppress different centers of the brain including those involved with attention, language and memory. A new paper in PNAS used TMS to disrupt part of the brain involved in judging intention and morality. Here is a summary:
Magnets can alter a person's sense of morality, according to a new report in the Proceedings of the National Academy of Sciences.
Using a powerful magnetic field, scientists from MIT, Harvard University and Beth Israel Deaconess Medical Center are able to scramble the moral center of the brain, making it more difficult for people to separate innocent intentions from harmful outcomes….
Magnetic fields made people judge outcomes more than intentions.
The effect was small and temporary but no less disturbing especially if the effect could be made to operate at a distance. Perhaps the tin-foil-hat-people have had it right all along.